THE FOUNDING OF METALS: A PRACTICAL TREATISE ON The Melting of Iron WITH A DESCRIPTION OF THE FOUNDING OF ALLOYS; ALSO, OF ALL THE METALS AND MINERAL SUBSTANCES USED IN THB ART OF FOUNDING. COLLECTED FROM ORIGINAL SOURCES, BY EDWARD KIRK, PRACTICAL FODNDKYMAN AND CHKMIST. Twenty-one Illustrations. V %' ^^^-^"^ .^U'.^ >...f ' ,-,-, r SHARON, PA. 1877. oi WASH s>^ ^^.V Entered according to Act of Congress, in the year 1877, . By EDWARD KIRK, In the office of the Libi-ai-ian of Congress at Washington, OnAr.r.Es Van BF.NTHUYf?RN & Sons, Printers, Biiidcra and Paper Manufacturei'S, Albany, N Y. / PREFACE. In ten years spent at molding-, and in the foundry business, and four years in traveling through the United States, in intro- ducing a chemical flux", for iron, I have seen the lack of regular- ity, and the bad effects of it, in the construction and manage- ment of foundry cupolas and furnaces, and the want of a guide or rule for their construction and management. At the earnest solicitation of many foundrymen, I have undertaken the publi- cation of this small work, with a view of throwing some light upon the subject of melting iron, and the construction and man- agement of cupolas and furnaces — a subject that always seems to be enshi'ouded in mystery. All the theories that I have advanced in this work, are from notes taken from practical observation, while visiting diiferent foundries, in the flux business, and from a chemical knowledge of the laws of combusti(/n and heat, as well as of the laws of chemical affinity of one element for another. By giving a few explanations of causes and effect, I hope to establish some regu- larity in the melting of iron for foundry purposes. I have also added a few recipes for the forming of alloys, and a general description of all the metals, minerals and gases used in the art of founding, as well as their application, all of which I have endeavored to place before the reader, clothed in popular language, so that all who can read may fully understand this interesting subject ; for this reason, I have endeavored to avoid using any of the chemical and technical terms which are usually applied to this subject, as they often have a tendency to embarrass, rather than to enlighten, the reader. THE AUTHOR, CONTENTS. Page. Iron 1 Mixing and melting irons. ... 14 Hard iron 19 Hard and soft iron 21 Soft iron 22 Burnt irons 23 Shot-iron 24 Shrinkage of iron 26 Coal 26 Large coal 27 Small coal 27 CoKe 28 Coal and coke 29 Charcoal 29 Cupolas 30 Construction of cupolas 31 The foundation 31 Bottom plate 32 The iron bottom 33 Caisson or shell 33 Cupola stack 34 The scaffold 35 Charging-door 35 Elevators 36 Scales 37 Lining 38 Fire-brick 39 Tuyeres 40 Different shaped tuyeres 41 Capacity of copolas 44 High and low cupolas 44 McKenzie cupola 48 Return-flue cupola 49 Straight cupolas 50 Daubing the cupola 52 Swivel cupola 56 The sand bottom 58 Front or breast 59 Two fronts or breasts 59 The spout 60 Stopping bods 60 Stopping or bod sticks 61 Tapping bars 61 Lighting the fire 62 Charging with coal 63 Coal melters 64 Charging with coke 65 Coke melters 65 Fig-ii-on 66 Pressure of blast 66 Page. Dumping the cupola 67 Fire in the dumps 67 The dumps 68 Pig-mold for over-iron 68 Combustion and heat 69 The melting point 72 Blast machines 76 The atmosphere 78 Fluxes and fluxing 79 Limestone flux 80 Oyster-shell flux 82 Fluor-spar flux. 82 Marble spalls flux 82 Patent fluxes 82 Charcoal flux 83 Potato flux 83 Clean iron and sound castings 83 Polling iron 84 Slag 84 Daubing for ladles 85 Ladle rest 86 Percentage of fuel. . . .' 86 Percentage of fuel and cast- ings 96 Iron lost in melting 98 Melters 102 The old melter 103 Practical and scientific melt- er 105 Smart- Alic melter 107 Hot-blast cupolas 112 Reverberatory furnaces 115 Your neighbor and you 119 Scraps 122 Malleable iron castings 123 The founding of alloys ... 131 Metals and recipes for alloys 133 Alloys of iron 134 Platinum alloys 136 Gold alloys 13() Silver alloys 137 German silver alloys 138 Bismuth alloys 139 Brass alloys 140 Lead and copper alloys 141 Bronze alloys 141 Bell -metal alloys 143 Type-metal. 144 Lead alloys 144 Spelter-solder alloys 145 VI CONTENTS. Page. Hard-solder alloys 146 Soft-solder alloys 147 Babbit anti-friction metal . . . 147 Fluxes for alloys 148 Black flux 148 Nature and character of al- loys 149 Fusibility of alloys 151 Brass furnaces 155 Crucibles 157 Cupel 161 Blow-pipe 161 Brazier's hearth 163 Burning together 165 Hard-soldering 166 Soft-soldering 171 Table of metals 176 Gold 178 Silver 185 Platinum, palladium, rhodi- um, iridium and osmium. . . 188 Platinum 188 Palladium 189 Rhodium 190 Iridium 190 Osmium 190 Mercury 191 / Copper 192 Zinc 194 Tin 196 Lead 198 Nickel 199 Antimony 200 Bismuth 201 Arsenic 202 Manganese 202 Magnesium 203 Alluminum 203 Chromium 204 Cobalt 204 Potassium 204 Sodium. 205 Minerals AND GASES 207 Fuels 207 Mineral charcoal 208 Page. Anthracite coal , 208 Brown coal 209 Bituminous coal 210 Peat 214 Clay 214 Fire-clay 215 Loam 216 Potter's clay 217 China clay 218 Soap-stone , 219 Asbestos 219 Sands 221 Calcium 222 Marble 224 Lithographic stone 224 Pummey-stone 225 Silicon 225 Barium 225 Emery 226 Garnets 226 Amber 227 Alum-slate 227 Asphaltum 228 Sulphur 229 Phosphorus 230 Petroleum 231 Boron 233 Iodine 233 Chlorine 233 Bromine 231' Fluorine 234 Salt 234 Oxygen 235 Hydrogen 238 Nitrogen 239 Carbon 242 Atmosphere 250 Water 253 Combustion 260 Spontaneous combustion .... 264 Bronzing 265 Zincing 268 Blacking iron castings 269 Recipes for working steel . . . 270 Cement 271 IRON. The metal (iron) has been known from the very re- motest ages of the world ; for we read in the scripture that Tubal-Cain was an instructor of every artificer in brass and iron. We read of iron in almost all of the ancient histories, except the history of the ancient Greeks. At the very earliest period of their history they do not seem to have known of the existence of* iron, — far less the methods of working iron ; yet we read of iron in the histories of nations that were before the ancient Greeks ; and there is good reason to believe that, anterior to the earliest historical records of the Greeks, iron and the processes of working it were known in China and Hindostan. Yet, notwithstanding the fact that iron has been known from the very remotest ages, it does not seem to have been in general use in ancient times ; for in ancient history, as well as in the Bible, we read of very few purposes to which iron was applied; for all the tools, cooking utensils, and arms and implements of war of the ancients seem to have been made of brass or bronze, and alloys of different metals. "Whether the ancients did not know the value of iron, or whether they '' went in " for the more showy alloys of metals is not known ; but for some reason the art of working iron was not cultivated by any of the ancient nations as was the art of making alloys of 2 FOUNDING OF IRON. brass, bronze, etc. ; and all of the ancient nations seem to have understood to perfection the art of making and hardening brass and bronze, — an art that has been lost to modern nations. Yet, while we have lost the art of hardening bronze, we have discovered the art of hard- ening and tempering iron or steel, — an art that does not seem to have been known to the ancients ; and the art of hardening and tempering iron or steel is of more importance to modern nations than the art of hardening bronze. Although the metal (iron) has been produced from some of the several metalliferous sources from the earliest historical periods, yet new methods of working it, and new sources from which to obtain it, have multiplied so much in modern times as almost to rank in importance with the discovery of the existence of a new metal. Iron has been discovered in all parts of the world in large quantities, and is manufactured and worked by all civilized nations. The abundance of iron every- where indicates how indispensable the Creator deemed it to the education and development of man. There is no California of iron ; each nation has its own supply. Iron has come into such general use in modern times that the development of the iron resources of a country may readily indicate the advancement of a nation ; for iron has become the symbol of civilization ; its value in the arts can be measured only by the progress of the present age, in its adaptation to the useful arts ; it has kept pace with the scientific discoveries and improve- ments, so that the uses of iron have become universal ; it is worth more to the world than all the other metals combined. We could dispense with gold and silver, for they largely minister to luxury and refinement ; but notwithstanding their nobility, they must yield the palm to iron, which represents solelj'"the honest industry of labor. Iron is fitted alike for the massive iron can- non, for the great Atlantic cable, and for the watch FOUNDING OF IRON, 6 screws, so tiny that they can be seen only by the micro- scope, appearing to the naked eye like grains of black sand. For the last century almost all of the civilized nations of the world have seemed to vie with each other in the production of iron ; and to this fact we owe all of our modern improvements in the manufacture and work- ing of iron. In these new inventions and improvements the Americans have kept pace with the world ; and why should we not keep pace with, or lead the w^orld in the productions of iron ? for our resources of iron ores and fuels are unlimited, and all that is necessary is to de- velop them. Iron is sometimes found native, but it is a mere curi- osity of no practical value whatever. Meteors, contain- ing as high as ninety-three per cent, of iron, associated with nickel and other metals, have fallen to the earth from space. Iron is found in combination with almost all of the known elements, and in all parts of the world ; ic is found in our blood, in the blood of animals, and in the ashes of plants. Many minerals contain it in considerable quantities ; and in fact there are very few minerals entirely free from it.' But the principal source from which we obtain our supply of iron is from the oxides and carbonates of iron or iron ores. These ores are known by different names derived from their different chemical constituents, and from the different localities from which they are obtained ; as the red hematite, the brown hematite, the black band, the spar ores, the magnetic ore, the iron pyrites, the Lake Supe- rior ore, the bog ores, the Iron mountain ore, etc. All these ores contain more or less iron, locked up with oxygen in an apparently useless stone, and some of them are very rich in iron. The Iron mountain ore, which is found in the State of Missouri, is said to con- tain ninety per cent, of iron, and is the richest iron ore in the world. To obtain our supply of iron from these ores, we have only to separate the iron from its combi- 4 FOUNDING OF IRON. nation with the non-metallic part of the ores. This is done by roasting and smelting the ores in blast-furnaces. These furnaces are of different sizes, and are called one-eighth, one-fourth, one-half, and full stacks ; they are also divided into different grades, from certain obvi- ous peculiarities in their construction and mode of working, and fuel used, — as the cold-blast, the hot- blast, the charcoal, the coke, or the anthracite furnaces. From these peculiarities of the furnaces the iron pro- duced receives their different names, — as the cold-blast and hot-blast, charcoal irons, the coke iron, and the anthracite iron. The cold-blast furnace is a furnace that is blown \\A h a cold blast, or cold air. This class of furnaces always use charcoal fuel, and they produce the best class of iron for machinery or any heavy work that requires great strength, such as rollers for rolling- mills, cannon, shafts and cranks for machinery, etc. This class of iron, although it runs soft in any heavy casting, will generally run hard in light castings ; and it is never used in stove foundries, or in any foundry where light work is made. The cold-blast iron is the best iron for chilling, and is used in the manufacture of car wheels, crusher-jaws, and any castings that require a hard chilled surface. The hot-blast charcoal furnace is a furnace that uses charcoal as a fuel, and is blown by a hot blast. This furnace has an oven, filled with coils of pipe which are heated to redness. The cold blast is forced through these pipes, and then into the furnace ; and when it enters the furnace it is heated to redness, and is termed hot-blast ; and the products of this class of furnaces are termed hot-blast charcoal iron. This class of iron is the best iron that can be procured for general foundry purposes ; for it may have both hardness and softness, and it has great strength, but it has not got the chilling properties of the cold- blast charcoal iron. This class of iron is extensively manufactured in the south-eastern part of Ohio, along FOUNDING OF IRON. 5 the Ohio river, in what is known as the Hanging-rock iron region ; and the iron produced is termed Hanging- rock charcoal iron. The furnaces in this region are all small furnaces ; in fact, all charcoal furnaces are small, none of them being over one-eighth or one-fourth stacks. The Hanging-rock irons are principally used for foun- dry purposes ; and in the foundries through the southern parts of Ohio, Indiana and Kentucky there is very little iron used but the Hanging-rock irons. The coke fur- naces are the furnaces that use coke as a fuel. All coke furnaces are hot-blast furnaces ; this class of furnaces is principally located through Western Pennsylvania, and along the Ohio river, and through the Western States. The products of these furnaces are termed coke iron. This iron is sometimes used in foundries ; but the prin- cipal part of it is used in rolling-mills in making wrought irons. The coke furnaces are the largest fur- naces in this country. The Luey furnace and the Isa- bell furnace, at Pittsburg, are twenty feet in diameter on the inside ; these furnaces have each produced over a hundred tons of pig-iron every twenty-four hours. There is a very large coke furnace at Irington, on the Ohio river ; that was put in blast about two years ago ; this furnace is said to be the largest and best furnace in the world; it was built by the iron men of the Hanging-rock region. A man was sent all over this country and Europe to get all the modern improve- ments for it before its construction, and it has all the modern improvements combined, and is said to be per- fect. The anthracite furnaces are the furnaces that use anthracite coal as a fuel. All of this class of furnaces are hot-blast furnaces, and the product is termed an anthracite iron. This class of iron is extensively used in foundries, and is a good iron for stove plate and all kinds of light castings. The anthracite furnaces are principally located through the eastern part of Penn- 6 FOUNDING OF IRON. sylvania, and in New York, New Jersey and Maryland, and are generally small furnaces. A great many improvements have been made in blast- furnaces in the last few years, and they have been brought to a state of comparative perfection; but most all of these improvements have been made with a view of increasing the yield oF iron from the ores and of mak- ing a cheaper iron. Most all of these improvements have had a tendency to deteriorate the quality of the iron rather than improve it, so that the foundrymen have a worse iron to work, to-day, than they had some years ago. To smelt iron from its ores, in the blast-furnace, the ores, fuel and limestone are put into the furnace together in layers or charges ; the fuel is to create heat and smelt the iron from the ores ; the ores are to produce the iron, and the limstone is to act as a flux and impart igneous fluidity to the non-metallic residue of the ores and fuel, and carry it out of the furnace in the shape of slag or cinder. Practice has demonstrated the fact that, by mixing two or more ores in the furnace, the impurities in one ore may be made to impart igneous fluidity to the non-metallic residue of the other, and furnaceraen have adopted the theory of using two or more ores, each having diff'erent chemical constituents, and in so doing, less limestone is required as a flux in the furnace. As the iron is smelted from its ores, it drops into the hearth or bottom of the furnace, and is drawn off in a channel cut in the sand in the floor of the casting-house, and from this main channel it is run into molds or pigs. As the iron chills in the mold it is called pig-iron or cast-iron, and the iron remaining in the large channel is called the sow-pig — hence the term pig-iron. There are a great many diff'erent varieties of iron ; the principal ones are cast-iron, wrought-iron and steel. The difference between these irons is caused by the different proportions of carbon and other impurities FOUNDING OF IRON. 7 which they contain. Cast-iron or pig-iron is the form of the iron as it comes from the I last-furnace ; it is brittle and cannot be welded, and it is neither malle- able nor ductile. This iron expands at the moment of solidification, so as to copy exactly every line of the mold into which it is poured, and it contracts on cool- ing. These qualities fit it for casting into sand or other molds ; and these castings may be made so soft as to be easily filed or turned, or they may be made so hard, by chilling in an iron mold, that no tool will i ut them. Cast-iron contains from two to five or six per cent, of carbon, and as the carbon increases or diminishes, the iron becomes harder or softer, and is termed a No. 1, 2 or 3 iron. That which contains the most carbon is the softest iron, but it is not always the strongest iron. As the carbon decreases, the cast-iron grows harder, ^ and after it gets past a certain point it grows weaker. Cast-iron is often combined with other substances as well as carbon ; it has a great affinity for sulphur, phos- phorus, silica, and other impurities; it is also often alloyed with manganese, forming speigel-eisen iron ; with chromium, forming chromic iron ; with copper, forming red-short iron ; with lead and other metals, forming cold-short iron. These alloys often cause cast-iron to be hard as well as brittle. Wrought-iron, as it is termed, is cast-iron that has been deprived of its carbon and some of its other impu- rities. This is done by burning the carbon from the cast-iron in a current of highly-heated air in a reverb- atory furnace. The iron is melted in the furnace, and is stirred and boiled up and exposed to the heated air by means of long puddling-bars, as they are termed. After it has been stirred and boiled until it ceases to be fluid, it is then worked into balls and is taken out of the furnace while white-hot, and crushed in the squeezers or under the trip-hammer, to force out the slag and convert it into blooms. It is then run through 8 FOUNDING OF IRON. grooved rolls to bring the particles of iron nearer each other and give it a fibrous structure ; and by means of rolling, it is converted into bar-iron, sheet-iron, etc. It is then malleable and ductile, and can be forged and welded ; yet in bailling and puddling cast-iron to con- vert it into wrought-iron, it is impossible to separate or burn away all of the impurities, or other metals that may be alloyed with the cast-iron, so that, in wrought- iron as in cast-iron, we have three divisions of iron — as red-short, cold-short, and neutral-iron. The red-short iron is an iron that is brittle when red-hot, and strong when cold. This class of iron is not used for bar-iron or any other iron that requires to be heated or forged, but it is principally used for sheet-iron, cut-nails, etc. Cold-short iron is an iron that is brittle when cold, but .is very tough when hot. This quality fits it for forging better than any other iron, but as it has very little strength when cold, it is seldom used alone except for cheap grades of bar-iron. Neutral-iron is an iron that is neither brittle when cold or hot, but is between the extreme red-short and cold-short irons, and it is made by mixing the red-short and cold-short irons together. The neutral-iron is the best iron for all kinds of bar- iron, and all our best bar is made from it. Steel is an iron that contains less carbon than cast- iron, and more than wrought-iron. It is made by con- verting cast-iron into wrought-iron, and then adding a small percentage of carbon by heating wrought-iron bars in a box or oven surrounded by charcoal. These bars of carbonized iron are then melted in crucibles and cast into ingots, and are called cast-steel ingots ; hence the term cast-steel. It is said that the inventor of cast- steel was a watchmaker named Huntsman, who lived at Atterclitfe, near Sheffield, in England, in the year 1760. He became dissatisfied with the watch-springs in use, and set himself to the task of making them homogeneous ; — if he could melt a piece of steel and FOUNDING OF IRON. 9 cast it into an ingot, its composition would be the same throughout. He succeeded ; his steel became famous, and Huntsman's ingots were in universal demand. He did not call them cast-steel, for that was his secret. The process was wrapped in myster}^ by every means ; the most faithful men were hired"; the work was divided; high wages were paid, and stringent oaths taken. One midwinter night, as the tall chimneys of the Attercliffe steel works belched forth their smoke, a belated trav- eler knocked at the gate; it was bitter cold; the snow was falling fast and the wind howled across the moor. The stranger, apparently a common farm-laborer seek- ing shelter from the storm, awakened no suspicion ; the foreman of the works scanning him closely, at last let him in. He feigned to be worn out \vith cold and fatigue, and sank upon the floor and was soon seem- ingly fast asleep. That, however, was far from his intention ; he cautiously opened his eyes and caught a glimpse of the mysterious process ; he saw workmen clothed in rags, and wet to protect them from the tre- mendous heat, draw the glowing crucibles out of the furnaces and pour their contents into molds. Hunts- man's steel works had nothing more to disclose, and the secret of cast-steel was stolen. The value of steel de- pends largely upon its temper ; too much carbon causi^s steel to be poor and too much like cast-iron ; too little carbon causes steel to be like poor wrought-iron ; hence the importance of having just the proper amount of carbon. Steel is tempered by heating and cooling it suddenly by plunging it into cold w^ater, oil, damp sand or anything that will draw the heat from it suddenly. The workmen decide the quality of the temper by the color of the oxide that forms on the surface of the vari- ous kinds of work requiring different tempers. Cold chisels and machinists' tools require a straw-blue tint ; razors require a straw-yellow ; springs and swords, a bright blue, and saws a dark blue. 10 BOUNDING OF IRON. In the last few years several new processes of making steel, direct from the pig-iron, have been introduced, and are now in operation. The principal process in use at the present time is the Bessemer process. This pro- cess of making steel consists in melting several tons of pig-iron in a cupola, and pouring it into a large con- verter, hung on two pivots, so as to be easily tilted. Air is driven into the converter through the bottom, and is forced up through the molten metal, causing it to bubble and boil, and producing an intense combustion. The roar of the blast, the hot, white flakes of slag, ever and anon whirled upward, the long flame streaming out at the top of the converter, variegated by tints of different metals, and full of sparks of scintillating iron, all show the play of tremendous chemical force. The operation takes about twenty minutes, when the iron is purified of its carbon ; and silex, enough speigel-eisen cast-iron — an iron rich in carbon and manganese — is then added to convert it into steel. Then it is poured out and cast into ingots. It is then hammered or rolled into any desired shape. The Bessemer steel is princi- pally used for railroad steel rails. Pure iron is far more rare and more difficult to obtain than absolutely pure gold ; it is only met with in chem- ical laboratories, and very seldom there. Wrought-iron, however, is considered as pure iron ; but it is only com- mercially pure, as it always contains more or less impurities. Cast-iron is iron combined with some four or five per cent, of impurities. Witl^ a view of getting rid of the four or five per cent, of impurities contained in cast-iron, and giving us a purer wrought-iron, the puddling process was invented by Richard Corts. The steam jet and atmospheric-air process was invented by Mr. Plant. The process of applying either air or steam from below was invented by Mr. Martin. The process of refining iron by a process of granulation was invented by Mr. Clay ; and several other processes of refining FOUNDING OF IRON. 11 iron have been invented. The object of all these in- ventors has been to rob the cast-iron of its four or five per cent, of carbon, or impurities. That this four or live per cent, of carbon in cast-iron is not barren of all good results, will be seen by a consideration of the products made of cast-iron and wrought-iron respect- ively. Cast-iron, by losing its carbon, loses its fluidity, and wrought-iron is almost infusible ; yet, by virtue of its malleability and power of adhesion under the opera- tion of welding, wTought-iron may be converted into a multitude of useful forms. But if we look over the comparative numbers and variety of the products of cast-iron and wrought-iron respectively, and reflect on the advantages of the fluidity imparted to cast-iron by its impurities, we will rise from the survey with the conviction that the existence of these impurities in cast-iron is not without its advantages ; for to these impurities we owe the enormous development which the products of cast-iron have attained. If cast-iron was deprived of its carbon the genus of smelting and casting operations would all be gone ; and, instead of the facility wherewith the genus of our smelting and casting operations enable us to turn out enormous quan- tities of iron cast into the form required, every piece of manufactured iron would necessarily have to be manu- factured by the laborious operation of forging, ham- mering and welding; the price of iron for many purposes would be enhanced in value, and, for numerous pur- poses to which it is now applied, it could not be used at all. Imagine the pieces of cast-iron that constitute the anchors of the Brooklyn bridge, and contemplate the ]3rice of wrought-iron pieces of the same circumfer- ence, having the same weight, form and dimensions, hammered and welded into shape, instead of cast ; it would have been utterly impossible to have made them, notwithstanding the aid of our ponderous steam ham- mers. The ease with which a blacksmith heats, and 12 FOUNDING OF IRON. welds, and fashions into shape upon his anvil the glow- ing wronght-iron, conveys but a feeble indication of the diificulties which beset the working of wrought-iron in large masses. It is difficult to establish the extreme limits or size of which a piece of wrought-iron admits of being forged ; but there is a limit reached by the failure of power to heat the mass of metal to the welding heat, and by the tendency of wrought-iron, in large masses, to crystallize and lose its fibrous structure when subjected to a long continuous heat. As has been inti- mated, almost all of the new inventions and improve- ments in the manufacture of iron have been introduced with a view^ of making wrought-iron or steel ; and the inventors of these processes have attempted to make almost every product of iron out of wrought-iron or steel ; and in some of these undertakings they have succeeded, and in others they have failed. In fact, they have failed or accomplished nothing in all cases where they have attempted to apply wrought-iron in large masses in place of cast-iron. It is true that wTought-iron* shafts, cranks, plates for gun-boats, etc., have been manufactured, and have given better results than the cast-iron of to-day would have done, but they are no better than the cold-blast charcoal iron of the past, or the cold-blast charcoal iron of to-day. Heavy cannon have been made of wrought-iron, but in almost every case they have proved failures. Steel cannon have been made, and several very large ones were on exhibition at the Centennial Exhibition at Philadelphia. These cannon are said to be superior to either the wrought-iron or cast-iron guns ; but they have not been brought into general use yet, and little can be told about them by the few that have been made as experi- ments ; but there is no doubt but what the steel gun can be made superior to the iron gun made from hot- blast iron ; for we can add enough carbon to steel to make it a refined cast-iron, and still be called steel. FOUNDING OF IRON. 13 The improvements in the manufacture of wrought-iron and steel have become matters of actual necessity ; for all the improvements in the construction of blast-fur- naces and the productions of cast-iron have had a ten- dency to make a poorer iron. When we had the char- coal iron it was a superior iron, aud it answered many purposes to which wrought-iron is now applied; but when the hot blast was introduced, aud the use of anthracite and bituminous coal or coke was adopted as a fuel, cast- iron no longer had the purity of the charcoal iron, but was deteriorated by the impurities contained in the fuel. Analysis of coal or coke-smelted iron demon- strated the existence of both sulphur and phosphorus incorporated with it ; the analysis also demonstrated that these impurities w^ere in direct proportion to their proportions contained in the fuel, and to overcome these impurities the manufacturers of wrought-iron have adopted new ways of working and manufacturing their irons. But the foundrymen have jogged along in the good old way, and took the pig-iron as they got it, and turned out castings accordingly ; and while the wrought- iron manufacturers have kept up the standard or im- proved the quality of their iron, the foundrymen have made a weaker casting, so that a great many things are now made of wrought-iron that were made of cast- iron in times past. When we look over the coun- try and survey the respective products of cast and wrought-iron, and see the hundreds of tons of castings that are turned out of our foundries daily, the enormous amount of stoves that are manufactured, and contem- plate the endless amount of trouble that the foundry- men have in getting an iron that will make a first-class casting, the question naturally arises : Why does the inventor not start at the blast furnace and improve the iron in the pig, instead of at the rolling-mill ? I see no reason why he should not, unless it is that the wrought- iron manufacturer is ambitious to make a good iron, and 14 FOUNDING OF IRON, offers some inducements to inventors, while the foun- drymen are only ambitious to make a cheap casting and undersell their neighbors, and offer no inducements to inventors. MIXING- AND MELTING IRONS. The foundryman cares little or nothing for a chemical analysis of iron, which merely shows the exact amount of different impurities it may contain ; but the question that the foundryman asks, is : What irons can I work, and how can I mix them so as to produce a good, clean, strong and cheap casting ? This is a question that is almost impossible to answer, as it is impossible to give a complete vocabulary of all the impurities which iron may contain, with their effect upon the iron in different proportions, as these proportions may be varied in re- melting and produce different results ; and even if it were possible, the foundryman does not wish to go to the trouble of making a chemical analysis of every lot of iron he gets in, to ascertain its impurities and to keep track of how it may be mixed with some other lot of iron. Little can be told by looking at an iron in the pig, whether it will run hard or soft when remelted and run into castings, or whether it will mix with another brand of iron. The foundryman, or an expert, may by actual tests become acquainted with all the iron and ores used in a certain locality, and, by looking at the iron in the pig, tell very nearly what it will do when run into cast- ings ; but the best expert in the country can tell little or nothing about an iron that he has not been accus- tomed to working, and he will often be deceived in those he has been accustomed to, by merely looking at the iron in the pig. True, he may make a good guess, and he may tell whether an iron will run extremely hard FOUNDING OF IRON. 15 or soft, but that is all that can be told by the looks of an iron in the pig. It is impossible to qualify the various kinds of pig- iron brought into the market by local terms and marks. It would not, after all, be of any use, because the fur- nacemen may change their ores or their mode of charg- ing the stock, and change the product of the furnace from a No. 1 iron to No. 2, or even No. 3 iron, which makes a great ditference in its application in foundries ; or a furnace may change the quality of its iron without any change of the ores, and without any apparent cause for the change in the quality of iron. When operating at Lewdsburg, Pa., last spring, I found a lot of pig-iron that was made at the Dry Valley Furnace, Pa. This iron, when remelted and run into a cylinder head that was nearly two inches thick, was so hard that it could not be drilled, yet the iron in the pig was of a dark-gray color with a large open crystal, and to all appearance was a No. 1 soft foundry iron. This iron was made from the same ores that the furnace had been using for years. In making a No. 1 foundry iron, no change had been made in the mode of stocking the furnace, and there was no apparent cause for the change in the quality of iron. This furnace, after it had been in blast for a short time, got to working so badly that it became necessary to blow it out. It was then found that when putting the furnace in blast, it had scaffold on one side, which was the cause of the hard iron. If a blast furnace, with the fire only on one side of it, will change the nature of iron as this furnace did, then a cupola, with the fire or the blast all on one side of it, 'will change the nature of iron when remelted. I have seen two cupolas melt- ing the same iron, and one produced good soft, strong castings, and the other produced hard or brittle cast- tings. I have always found that the cupola that produced the hard or brittle castings, either had the blast all on one side of it, or that the fire was not 16 FOUNDING OF IRON. burnt up evenly, and that the stock was not charged regularly. Cast-irons admit of a division into three classes and seven grades. The three classes are : the red-short, the cold-short, and the neutral-iron. The seven grades are the seven qualities or seven numbers of iron, as No. 1, No. 2, or No. 3. Red-short iron is an iron that has no strength when red-hot, aud has a great deal of shrink- age. An extreme red short iron will shrink as high as one-fourth of an inch to the foot. Red-short iron, when used for casting pipe on their end, will cause the body of the pipe to shrink down and leave the bowl of the pipe before the iron has thoroughly set ; and when used in other castings, such as grate-bars, it will tear off and form cracks in the corners while hot : it will cause chill-cracks on the tread of a car wheel, but they are not deep and do not injure the wheel. Red short-iron may be either hard or soft, and is liable to go to ex- tremes either way. It never breaks from shrinkage when cold. Cold-short iron is an iron that has no strength when cold, and has very little shrinkage ; it will resist very little strain, and if the patterns are the least bit out of proportion the casting will break from shrinkage after it is cold ; it will cause stove-plates to crack under the sprews. Cold-short iron may be either hard or soft, and is liable to go to ex remes either way ; but it never breaks from shrinkage when hot. Neutral-iron is an iron between the extreme red- short and cold-short irons ; it is made by mixing the red and cold-short irons together. A neutral-iron is the best iron for foundry purposes, and furnacemen who make a business of manufacturing foundry iron make it a point to mix their ores so as to make as near a neutral-iron as possible. Yet in some localities one ore may be cheaper than another, and it may be used to excess, which may make an iron inclined to be either FOUNDING OF IRON. 17 red-short or cold-short, yet not extreme either way. The foundryman that is using three different brands of iron may find at times that he has two brands of iron inclined to be (;old-short, and one brand inclined to be red-short. If these three irons are mixed in equal pro- portions they will make a casting inclined to be extreme cold-short. Yet one-fourth of the two brands and one- half of the third brand, mixed together, may make a neutral-iron and a good strong casting ; or by leaving out one of the brands, and using one-half of each of the other two brands, the same results may be attained. The only practical way to ascertain whether an iron is either red-short or cold-short, is by actual tests in mixing and melting the iron in different proportions, and test- ing the strength and shrinkage. A neutral-iron should not shrink more than one-eighth of an inch to the foot. Stove-foundrymen should be careful to use as near a neutral-iron as possible, and to change their brands of iron as little as possible ; as the changes of iron often change the shrinkage, and will make trouble in mount- ing the stoves when much odd plate is kept on hand. When new brands of iron are introduced, test bars should be made to ascertain the shrinkage, and the different brands of iron should be varied so as to keep the shrinkage as near alike as possible. The same theory may be followed in mixing irons to make a soft iron, thus : three brands of iron, mixed in equal proportions, may make a hard iron, while any two of the same brands, mixed in equal proportions, may make a soft iron. Tests were made last fall at Perry & Co.'s stove works in melting the three brands of iron, viz.. Crane, Hudson and Jagger. These three irons were melted at the rate of fifteen per cent, of Hudson to eighty-five per cent, of Crane and Jagger together. This mixture made a hard iron. One-third of each brand was then melted together, and made a hard iron. 0n3-half Hudson to one-fourth Crane and one-fourth 9 18 FOUNDING OF IRON. Jagger were then tried, and the result was a hard iron. The Hudson and Crane were then tried together — one- half each — and made a good soft iron. The Hudson and Jagger were then tried together — one-half each — and made a good soft iron. The Crane and Jagger were then tried together — one-half each — and made a hard iron. Thus the Hudson would neutralize either the Crane or Jagger separately, but would not neutral- ize them when put together in any proportion. Iron will combine with almost all of the sixty-four known elements; and these elements, combined with irons in different proportions, will destroy the affinity of one brand of iron for another; and foundry men, in mixing their iron, will generally use equal proportions of all the brands of iron that they are using ; thus one- half, one-third or one-fourth of each brand. If the castings come hard, they will reduce the No. 2 and increase the No. 1 iron ; and I have often seen foun- dries that were using all No. 1 iron, that were still troubled with hard iron. This was because they were using irons that had no affinity for each other, and would not unite so as to form a homogeneous iron ; and throwing out the No. 2 iron gives only a temporary relief by the excess of carbon in the No. 1 iron, over- coming the non-affinity of the irons ; and if the No. 1 iron happened to be a little poorer, one day than another, the iron was hard and uneven. I have often seen foundrymen that had one brand of iron in their yard that they had had on hand for years, and could not use it ; and perhaps the next foundryman that I would meet would be using that same brand of iron, and could not get along without it. This was because the one foundryman was using other iron as a mix that had an affinity for that particular brand of iron ; or the two foundrymen might be using the same iron as a mix, and mixing them in different proportions, which produced different results. Two poor irons can often be FOUNDING OF IRON. 19 mixed together so as to make a good iron ; as is the case in mixing the extreme red-short and cold-short irons which forms a neutral iron that is superior to either the red-short or cold-short irons for foundry pur- poses. In mixing irons, I should recommend mixing them, and varying the mixture by the local brands or marks, and not by the numbers of the iron. To make a good iron, at least one-third of No. 2 iron should be used ; and if all No. 2 irons can be used and make a soft iron, they will make a superior casting to all No. 1 iron. In melting iron I should recommend melting it hot, and as fast as possible. A quantity of molten iren should be kept in the cupola, or in a large ladle, so as to give the different brands of iron a chance to mix. In most all the foundries at Wheeling, West Va., the cupolas are never stopped in from the time the blast is put on until the bottom is dropped. A large ladle is set on trestles in front of the cupola, in such a manner that the iron can run into it from the cupola, and be poured out into the smaller ladles at the same time. The iron is all run out of the cupola as fast as it is melted, and is mixed in the large ladle. I think this is a^ good way of mixing irons. See Alloys. HARD IRON. Most every foundryman is troubled more or less with hard iron, especially if they are manufacturing light castings. Hard iron is sometimes caused by using a poor quality of iron in the first place, or poor fuel, or by using too much shot-iron, or rusty scrap. The damp- ness in the sand bottom will cause the first iron to be hard. Iron boiling in a green ladle will be hard if run into light plates. Sand worked too wet, or rammed too hard, or spunged too much, will cause hard iron. Thus 20 FOUNDING OF IRON. hard iron may be traced to a great many causes ; but the principal cause of hard iron, when good stock is used, is the unscientific way in wh'ch cupolas are con- structed and charged. It is a well-known fact that Nos. 1, 2 and 8 irons are made in a blast-furnace from the same stock, — the different grades of iron being caused by the different temperature at which the ores are melted. If a large cupola is constructed with only one tuyere the blast cannot be forced into it so as to give an even temper iture : or if the tuyeres are not placed at equal distances apart, or if they are so placed that one or two of them will take nearly all the blast, and the balance of the tuyeres get little or none at all (as is often the case), the result will be an uneven temperature in the cupola, and an iron hard and soft in spots. Cupolas are often charged with large coal in the bed, which forms large crevices between the lumps, through which the cold blast penetrates to the center of the cupola, and strikes the hot iron as it drops through the coal and chills and hardens it. The bed is often put in without any regard to whether it is level or not on top when the iron is charged. The first charge of iron is thrown in, and the second charge of coal in the same hap-hazard way. If the cupola is large, and many gates or sprews are used, they will probably all be found in a pile on the side of the cupola, where it is handy to throw them from where the man stands that shovels them in. The iron will invariably be higher just under the charging door than anywhere else. The coal or coke is thrown in, and, if small, will roll to the lowest place ; thus having a large body of fuel in one place and little or none in another place. This uneven charging makes an uneven temperature, and a hard and soft iron ; or the iron may be charged even, and each charge leveled up, and the coal put in on it in large lumps (as is often the case), so that the small amount used will not more than half cover the iron, and will not separate the FOUNDING OF IRON. 21 charges of iron properly. The result is the same as when the charges of iron are not leveled up — an uneven temperature, and hard and uneven iron. I have seen two stove-plate foundries, in the same city, not more than two squares apart, melting the same brands of iron mixed in the same proportions, each using the same quality and same percentage of coal; and one foundry always had good soft iron, and the other one was always troubled with the iron running hard in spots. On examining the cupola, where the hard iron was made, I found it to be a round cupola four feet six inches in diameter, with a stack live feet or more in diameter. This cupola had five tuyeres ; one was di- rectly in front, and in line with the supply pipe ; the others were scattered around at irregular distances apart. The tuyere in front of the supply pipe was admitting almost as much blast into the cupola as all the other four tuyeres put together, especially towards the last of the heat, when the tuyeres became clogged up. The iron was put into the cupola in charges of 4,400 lbs., and the coal in charges of 350 lbs. The coal was put in in large lumps, and was not near enough to cover the iron, or separate the charges of iron properly. The stack of this cupola was too large to concentrate and equalize the heat, the tuyeres were not arranged so as to give an equal amount of blast to all parts of the stock, and the coal was not charged even enough to give an even heat, and the iron was not melted at an even temperature, which was the cause of the hard spots. HARD AND SOFT IRON. When hard and soft iron are melted in the same cupola, as is often the case in jobbing and small foun- dri'^s, the hard iron should be melted first one heat, and 22 FOUNDING OF IRON. soft iron first the next heat, as part of the last iron will always stick in the lining; and if the hard iron is melted last, and the soft iron first, the next heat the first few ladles will be more or less hard, from the small particles of hard iron remaining in the cupola from the former heat. Melting hard and soft iron in the same heat is a bad practice. SOFT IRON. To melt iron soft and even, with an even shrinkage, it must be melted at an even temperature, and the nearer we can come to a natural draft the better for the iron. The tuyeres should be put in at equal distances apart, and so arranged as to admit an equal amount of blast at each tuyere. The tuyeres should be of a size to correspond with the blast pipe from the fan or blower, and the fan or blower should be run to suit the cupola. A too sharp and cutting blast is injurious to the iron, and slow melting is equally injurious, so that we must have a mild blast and volume enough of blast to do fast melt- ing. The stack of the cupola should be small, and high enough to give the cupola a good, even draft ; the bed should be evenly lit up, but not burnt too much before the iron is charged. Small coal or coke should be used all through the heat, and each bed of coal or coke should be properly leveled up before the iron is charged on it ; so should each charge of iron be leveled up before the coal or coke is charged on it. The iron should be charged into the cupola from one to three hours before the blast is put on (according to the draft of the cupola), so as to have it heat up gradually and anneal. The iron should be put into the cupola in large charges, so as to give a good bed of coal or coke between the charges and separate them properly without using too FOUNDING OF IRON. 23 much fuel. When different brands of iron are used, the cupola should never be tapped close, but a few hun- dred of molten iron allowed to remain in the bottom of the cupola so as to give the iron a chance to mix. BURNT IRONS. When in the malleable-iron business, I often tried to melt the annealing boxes in a cupola, with coke, after they had been burnt out, but I could never produce more than fifty per cent, of iron, and the iron produced was so mixed with slag that it could not be used for castings without remelting. The iron produced ,was always white and hard. I made a test at the American Stove and Hollow-ware Company's foundry in Philadelphia, Pa., in July, 1874, in remelting an- nealing pots that had been used for annealing hollow- ware. These pots were about two inches thick ; they were charged in the cupola in the ordinary way, Le- high Valley coal being used as fuel. The result of this test was a product of about seventy per cent, of iron, which was so mixed with slag that it could not be run into castings ; the iron was also white and hard. The larger percentage of iron produced when remelting the hollow-ware annealing pots than was produced when remelting the malleable-iron annealing boxes, was caused by the hollow-ware pots being heavier and not so badly burnt, and not by the different fuels used in remelting. The best way that I have found for melt- ing burnt iron in a cupola is to put it in the cupola with the regular charges of good iron, a little at a time ; it will then act as a flux, and is better than limestone, especially if the iron is badly burnt ; but care should be taken to not use too much of it at a time, as it will harden the good iron if used in too large quantities. 24 FOUNDING OF IRON. SHOT-IRON. Every foundry has more or less shot-iron, or fine scrap, from the rattle barrels and gangways. This class of iron, although made from the best of pig-iron, will run hard when remelted, and in some cases will not mix with other iron (especially if the shot is rusted), but will cause hard specks in machinery or heavy castings, and will often sandwich in stove plate or light castings, forming a plate hard in the centre and soft on each side. Foundrymen who run exclusively on first class work have considerable trouble in getting rid of this class of iron, and it is often thrown out in the dump rather than remelt it. I made a test in remelting shot iron at the Baldwin Locomotive Works in Philadelphia, in June, 1874. In this test the shot-iron was put up in. wooden boxes, each box holding from seventy to eighty pounds ; one ton was then charged in a cupola, in the ordinary way, without any pig-iron or other heavy iron ; the result of this test was a white, hard iron when run into pigs, and a wastage of twenty-five per cent. I do not think that anything was gained by putting the iron in the wooden boxes, for the boxes were all burnt up before the iron even became hot. I also made some tests in melting shot-iron at a stove works in Louisville, Ky., in May, 1875. In these tests the shot-iron was charged on the first bed of coke, with a view of melting it first and using the iron for warm- ing the ladles, and then pouring it into the pig-bed or some heavy work. This way of melting the shot-iron was a success so far as getting rid of the shot and using the iron was concerned ; but it was found that the cin- der and dirt, mixed with the shot-iron, formed a coat- ing of slag and dirt over the bed and prevented the cupola from melting ; and a much larger percentage of fuel had to be used when the shot-iron was charged on FOUNDING OF IRON. 25 the bed. Tests were made at the foundry of Perry & Co., at Albany, N. Y., in melting a lot of shot-iron that had got mixed with fine coal, and in order to separate the iron from the coal, they thought they w^ould burn the coal under their boiler and melt the shot-iron, and have it run through the grate bars into the ash pit, and collect it in pigs. With this view, a thin layer of fine coal and shot-iron was spread over the fire, and the furnace closed up and the blast put on. Mica had been put into the furnace doors, so that the effect of the heat upon the iron could be seen. The result of this test was, that w^hen the iron came near the melting point the small shot threw off beautiful fiery stars of all col- ors and shapes, making a beautiful fire- works; and in these fiery stars all the iron was converted into the black oxide of iron, so that not a particle of iron could be found either on the grate bars or in the ash-pit at the conclusion of the test. I have observed, in making tests to ascertain the percentage of iron lost in melting, that the percentage of loss was always greater when the shot-iron was charged through the heat ; and from different tests that I have made in melting shot-iron, I have concluded that it should not be charged on the bed or in the first of the heat, because more fuel will be required to make hot iron. It should not be charged in small quantities through the heat, for it is too much exposed to the gases of the cupola, and the oxygen of the blast converts it into the black oxide of iron, and it is lost. I find that the best results are produced when the shot-iron is charged in a large body, as it was at the Baldwin Locomotive Works ; it then lays compactly together and the heat melts it before the oxygen of the blast can convert it into an oxide. I think the best way for melting shot-iron in a cupola is to charge it after all the other iron has been charged into the cupola ; it then forms a cover over the iron and prevents the escape of the heat, and the loss by the wastage of iron may be 26 FOUNDING OF IRON. made up by the saving of fuel. It also improves the quality of the shot iron to melt it at the last of the heat when the cupola is hot. Shot-iron, if melted and run into pigs, will mix with other iron w^hen remelted. Shot-iron has been melted in iron boxes or pots with about the same results as in the wooden boxes. SHRINKAG-E OF IRON. Irons will vary in shrinkage. Some irons will not shrink any, and others will shrink as high as a quarter of an inch to the foot. The average shrinkage, and the shrinkage always counted on in making patterns, is one-eighth of an inch to the foot. COAL. Lehigh Valley coal is considered the best coal for melting iron because it is harder than some of the other coals, and is more free from sulphur ; but coal from the Lackawanna Valley, and Schuylkill Valley, or Potts ville region, is also extensively used in the melting of iron in foundries. In selecting coal for the cupola, care should be taken to get as hard and solid a coal as pos- sible, and a coal that will not slack down when the heat strikes it. Most any of the anthracite coals can be used for melting iron in cupolas. When the coal is soft or poor, a much larger percentage of coal must be' used, and the charges of coal must be increased in weight towards the last of the heat, as will be seen by reference to melting done at the car worlds at Ber- wick, Pa., where the coal used was soft coal, from the Wilksbarre region. FOUNDING OF IRON. 27 LARG-E COAL. The majority of foundrymen and melters believe that it is impossible to melt iron without large coal, and they will always select the largest lumps they can get and put them in for the bed; some plate or other light scrap is then charged on the coal, to prevent it from being broken up by throwing in the pig or other heavy iron. This, they claim, makes a bed that will last longer and do better melting than a bed of small coal. The iirst charge of iron is put in on the bed, and then the second charge of two or three hundred of coal is put in in large lumps, as before, and probably will not more than half cover the bed of iron. The next charge of iron is then put in, and the next charge of coal in the same way, and so on. The blast is put on, and the cold wind finds the large openings between the large lumps of coal (which will naturally be formed by throw- ing large lumps of coal in a pile), and will penetrate to the center of the cupola before it becomes hot ; the iron is melted on top of the bed, and runs down through the large lumps of coal like water through a stone pile, and passes through the cold blast which is constantly coming in, and the iron is decarbonized, chilled and hardened. The "old-fogy " idea of using large coal for melting iron in cupolas is the cause of more hard and uneven iron than anything else. SMALL COAL. I have made some thorough tests in melting iron with different sized coal, and I have found that good melting can be done with any size if the coal is good. The Qgg size coal is a good size for small cupolas ; and what is known as grate or steamboat coal is the best size for 28 FOUNDING 0£ IRON. large cupolas ; and I should recommend it for the melt- ing of iron in cupolas in preference to large coal for the following reasons : It will pack closer in the bed than large coal, and will last equally as long ; the blast wdll be heated before it can penetrate any distance into the cupola ; the iron, being melted on top of the bed, will be slowly filtered down through the bed, and will be purified and superheated before it reaches the sand bottom. The second charge, of two or three hundred of coal, can be spread over the charge of iron so as to completely cover it and separate the charges of iron, — thus making the iron melt at a more even temperature, which will make a softer and a more, even iron. A smaller percentage of coal will be necessary than when large coal is used. Foundrymen should be careful when using small coal to get the best hard coal, as it produces the best results. COKE. Coke is extensively used for melting iron in cupolas for foundry purposes through the Western and South- western States. Connelsville and Pittsburg coke is considered the best coke for foundry purposes. The Steubenville and other Ohio cokes are sometimes used for melting iron; but they contain so much sulphur that they cannot be used in melting iron for stove- plate or other light work, as the coke does not have body enough to give life to the iron, and the sulphur hardens it and makes it brittle. Gas-house coke is sometimes used for melting iron, and does very w^ell when it is made out of Connelsville or Pittsburg coal ; but it has not as much body as the Connelsville or Pittsburg coke, and more of it has to be used to give life to the iron. G-as-house coke, made from cannel FOUNDING OF IRON. 29 coal, cannot be used for melting iron in cupolas. Poor coke will improve if left laying out in the weather for a long time. Wet coke seems to make hotter iron than dry coke. COAL AND COKE, When coke is used for melting iron in a cupola, a much larger heat can be melted than could be melted in the same sized cupola with coal. Coke will melt iron faster than coal. Coal or coke will make iron equally hot and fluid. Coal will make more slag than coke, and the cupola will be harder to pick out Avhen coal is used than when coke is used. Iron will take up sul- phur more readily from coke, and will be infused more from sulphur in coke than from sulphur in coal. Poor coke is worse than poor coal for melting iron. More blast is required for melting iron with coal than with coke. I have seen a great deal of melting done with both coal and coke, and I consider that equally as good melting .can be done with the one as the other. CHARCOAL. Charcoal will make iron softer, stronger, and more fluid than coal or coke. Yet, notwithstanding these facts, charcoal has, on account of being expensive, been generally abandoned as a fuel in the melting of iron in cupolas for foundry purposes, although it is still used in some parts of the country where w^ood is plenty, and coal or coke is expensive, or when the quality of the castings is more of an object than the expense of making tl\e,m. When charcoal is used for melting iron in a cupola, the cupola should not be as high as the coal or 30 FOUNDING OF IRON, coke cupola. Three or four feet is the best height for a charcoal cupola. The iron should be charged in small charges, and a mild blast used. Only small quantities of iron can be melted at a time with charcoal fuel. CUPOLAS. The cupola furnace has almost entirely taken the place of the reverberatory furnace for melting iron in foundries, because they have the advantage over the reverberating furnace of melting either a large or small amount of iron, and of melting it faster and hotter, and with less fuel ; but iron melted in the cupola furnace will not make as strong or as sound a casting as iron melted in the reverberatory furnace. To overcome this disadvantage, the foundryman has adopted the theory that he will sell you a casting cheap ; and if it breaks, he will sell you another one cheap. The cupola furnace has been in use for a great many years, and is almost as old an invention as the reverberatory furnace. Cupolas were first built in England and in this country, with a stationary fire-brick hearth or bottom ; and a^ large opening was left in the front, through which the dump or refuse was drawn out with hooks in place of dumping it by dropping the bottom. The large open- ing in the front was filled in with sand or loam, and a plate fastened in front of it to prevent it from being blown out ; and the tap-hole was put in the same as at the present time. The old style draw cupola, as it is called, is still in general use in England; and some few are still in use in this country in some of the Southern States. I saw three of them in use in a foundry in Baltimore two years ago. But the draw cupola has, as a general thing, been replaced in this country by the drop-bottom cupola, which is an American invention. FOUNDING OF IRON. 31 With a view of making some improvement in cupolas, foundrymen have constructed them in all shapes, and of all sizes and forms, and tuyeres have been put in in different shapes for admitting the blast into the stock. I have shown or described some of the principal cupolas in use at the present time that I have melted iron in or seen it melted in ; but I do not consider any of the new style or odd-shaped cupolas superior to the common straight cupola for melting iron, or for economy in fuel. In order to do good melting in any cupola, the lining must be kept in proper shape, as explained farther on. CONSTRUCTION OF CUPOLAS. When constructing a cupola, the first and most im- portant thing is to decide where it shall be put. In deciding this question, there are two things to be con- sidered ; the first is, where will it be the handiest to get the iron and fuel to it ; and the next is, where will it be the handiest to get the iron away from it. The latter is by far the most important point to be con- sidered, especially in foundries where light work is made. It is easier to wheel pig-iron to a cupola than it is to carry molten iron away from a cupola ; and the cupola should be set as near the center of the foundry as }K)ssible, so that the iron can be carried away from it in all directions, and so make the distance to carry it as short as possible. THE FOUNDATION. A good, solid stone foundation should be put down for the cupola to stand upon. If the foundation is not solid, it is liable to settle when the weight of the cupola 32 FOUNDING OF IRON. and stock comes upon it, and may crack the bottom plate, which will make trouble. The height that a cupola should be from the floor will vary according to the class of work that it is intended for. In stove-plate foundries, where the iron is all carried in hand ladles, the average height is from ten to twenty inches, and in ma- chinery foundries, w^here large ladles are used, the aver- age height is from two to three feet. When the cupola is very low, a pit should be put in, as shown in Fig. 10, so that the bottom can be dropped and the refuse taken away easily. This pit may be put in on any side of the cupola where it will be most convenient ; when put in front of the cupola, it may be covered with cast-iron plates, and the plates covered with a few inches of sand to prevent the iron flying, in case any is spilled. Cupo- las may be set on brick walls or on iron columns ; when the cupola is set high, the columns are the best, as they will last longer than brick, and are handier to get around. Care should be taken to not set the cupola too high, as the iron will sparkle and fly, in falling, into the ladles, and a great deal of it will be wasted in the course of time. BOTTOM PLATE. The bottom plate or ring upon which the cupola stands should be made of good, strong iron, and cast with strengthening ribs on it, so that it will not break when the weight of the cupola and stock comes upon it; for if the bottom plate once gets broken, it will always make trouble in putting up the doors and put- ting in the sand bottom, and make it more liable to cut through and run out. In small cupolas the bottom plate should only come flush with the insid.e of the brick lining, so as to allow the sand bottom to fall out easily when the door is dropped. In large cupolas the bottom FOUNDING OF IRON, 60 plate should project three or six inches inside of the brick lining, so as to make the door smaller and easier to handle ; when the bottom plate projects inside of the lining, the lining should be arranged as shown in Fig. 13, so as not to give the sand bottom too much bea.ring, and prevent it from dropping out easily. THE IRON BOTTOM. The cast-iron drop door, divided into two or more pieces, is generally used for the bottom ; it should be made as light as possible, so as to be easily raised. Wrought-iron doors are sometimes used on account of being lighter and easier raised ; they answer equally as well as the cast-iron doors. The door or doors should be supported by a good, solid prop under them, and not by a latch that is liable, to give way at any time and burn every one around the cupola. Slide bottoms are sometimes used for large cupolas ; these bottoms are divided in the centre and rest upon a slide at each end ; they are shoved forward into place with a bar and drawn back by a chain and windlass. The slide bot- tom makes a very good, safe bottom, but it is not always as convenient as the drop door. The iron bottom should be perforated with small holes, to allow the steam and gas from the sand bottom to escape without passing up through the molten iron. CAISSON OR SHELL. The caisson for cupolas should be made out of boiler iron, or heavy sheet-iron bars of angle iron should be riveted around on the inside of the caisson about three or four feet apart, so as to support the lining, and in 3 3-1 FOUNDING OF IRON. case part of it gives out, to admit of its being taken out and repaired without taking down the whole lining ; the angle iron also stiffens and strengthens the caisson, and is better than brackets. The old style, cast-iron stave caisson, with a brick stack, is still made and used in some parts of the country. They are more expensive than the boiler-iron caisson, and are not near so good, as the staves are liable to break from the expansion and shrinkage, and crack the lining and allow the blast to escape. The caisson should be well painted with coal tar, to prevent its rusting and make it last longer. The caisson will often rust through, and give way near the bottom in a short time. This is caused by the lining sweating and the moisture settling at the bottom ; and by putting in a heavy sand bottom and allowing no way for the moisture in the sand to escape, thi-s keeps the lower courses of brick always wet and damp, and the rust soon eats through the caisson. This trouble may be overcome by laying the first two or three courses of brick out one or two inches from the caisson, so as to fornf a small air chamber all around the bottom of the cupola. The bottom of the caisson should be perfo- rated with small holes to supply this chamber with fresh air, and allow the steam and moisture to escape. CUPOLA STACK. The diameter of the stack should not be more than one-half the diameter of the caisson, so as to concen- trate the heat. It should be drawn in just above the charging door, so as to throw the heat downward on the stock. The stack should be high enough to give the cupola a good and even draft ; a cupola with a good draft will melt better and make softer iron than one with a poor draft, for the nearer we can come to a nat- FOUNDING OF IRON. 6b ural draft the better for the iron. More power will be required to drive the fan or blower, when the cupola has little or no draft, for the blast has to be forced clear out at the top of the stack. I consider the stack one of the most important parts of the cupola. THE SCAFFOLD. The scaffold should be built large enough to keep stock sufficient for a rainy day or an accident, and have plenty of room to get around. The floor should be made of cast-iron plates, properly fitted together, so as to be fire-proof, and easy to shovel scrap or fuel off. The scaffold should be cleaned up, and the floor swept every day, so as not to get too much dirt and sand into the cupola. CHARG-ING-DOOR. The charging-hole should be large enough, and so arranged that the melter can throw in the iron with ease, and at the same time see where it lights and how it lays. The door should be made to fit close, and lined with fire-brick to prevent it from warping. A cast-iron door frame, filled in with fire-brick, makes the best door for a cupola. Two charging-holes are sometimes put in, in a large cupola (one on each side), for con- venience in charging the stock. Cupolas are arranged in this way at James L. Haven & Co.'s novelty foun- dry in Cincinnati, Ohio, and at Smith & Sons' pipe foundry in Pittsburg, Pa. Two charging-holes are generally put in, in all large cupolas where coke is used ^s a fuel. See Capacity of Cupolas. 36 FOUNDING OF IRON. ELEVATORS. There are a great many ways of getting the stock upon the scaffold. At some foundries, the iron and fuel is all thrown upon a platform, and from there thrown upon the scaffold. This is a very poor way of getting up the stock, as it makes a great deal of unnecessary handling of the iron, and there is a great deal of the fuel wasted by being broken up fine, so that it is not tit for use in the cupola. Other foundries have a run- way, and wheel up all the stock in wheelbarrows. This Is a better way of getting up the stock than throwing it up ; but it is very hard work wheeling up iron, espe- cially if the run-way is very steep, as it generally is. In most of the large foundries they have steam eleva- tors for taking up the stock. These elevators are very handy, and take up less room than a run-way does, and the saving in labor will soon pay for the expense of the elevator. The expense of running an elevator is very little ; for they are only run for an hour or two each day. There are several different kinds of eleva- tors in use in foundries ; but the principal one in use is the common straight steam elevator. Where it is desirable to carry the iron some distance, as Avell as elevate it, other kinds of elevators are used. In one foundry that I visited, where the stock was all kept in the cellar, an inclined-plane elevator was used for taking the stock upon the scaffold. This elevator was made by running two endless chains over two shive pulleys at the top, and two at the bottom, and fasten- ing shelves or buckets on to the chains. The stock was put on at the bottom and dropped off at the top as it went over the shive pulleys. This makes a very good elevator, and is better adapted to some foundries than the straight elevator. In other foundries an inclined- plane railroad is used, with a car drawn up by a rope FOUNDING OF IRON. 87 or chain. This style of elevating the stock is very good where it is kept in the yard, at some distance from the foundry, and where there is plenty of room ; but it is not so well adapted to foundries where room is an object. S CAL E S. A good pair of scales should be kept on the scaffold, and all the stock that goes into the cupola should be weighed accurately. The scales should be swept off after every draft, and kept in good order. Most foun- drymen think that any old scales are good enough for the scaffold, because they neither buy nor sell by them, but are merely dealing with themselves. It is very true that they are only dealing with themselves, and they are cheating themselves out of hundreds of dol- lars' worth of fuel every year. Some foundrymen do not have any scales at all on the scaffold, but depend upon the melter guessing at everything he puts into the cupola. G-uessing at the amount of stock charged is often the cause of slow melting, of dull iron, of irregu- lar melting, of running short of iron, and of burning out the lining in a short time, etc. There is not a foundryman in the country, who depends upon the melter to guess at the weight of the stock he charges, but what could save enough in one year to buy two or three pair of good scales by having his stock accurately weighed. There is nothing gained by having a good pair of scales on the scaffold, unless you see that the stock is carefully weighed, and no more fuel used than is actually necessary. 38 FOUNDING OF IRON. LINING-. A two-inch lining is heavy enough for a small cupola, and six or eight inches is heavy enough for any size cupola. In laying up a lining, the brick should be fitted closely together, so as to use as little mortar be- tween them as possible ; for, if too much mortar is used, it will crumble and fall out when the heat strikes it, and will leave openings through which the blast will escape. The best way to lay up a lining, is to have a bucket full of thin mortar or grout, and dip each brick into it as it is laid up. Each course of brick should be grouted between the brick and the caisson as soon as it is ksid ; if you do not grout between the brick and the caisson until two or three feet of brick have been laid up, the grout may not run down to the bottom, and will make a poor lining. When the lining is built three or four inches from the caisson, it may be filled in with molding sand properly tempered for molding, and rammed in solidly. This sand is better than grout, for it will not crack when it dries, as grout will. Stone lining should never be put in, except when it is impos- sible to get brick, as they are expensive to la.y up, and cannot be laid without using a great deal of mortar, which will soon fall out irom the excessive heat, and the stone will crack from being suddenly cooled when the bottom is dropped. Common brick will stand the fire better than stone ; the softer brick should be used. The lining should project out one or two inches just over each tuyere, to prevent the molten iron from drop- ping into the tuyeres. Some melters think that the caisson is air-tight, and the blast cannot escape, and it does not make any diff'erence if it does get out through the lining. These melters should remember that they are not trying to melt down the Iming, but the stock, and all the blast that escapes up through and back of FOUNDING OF IRON. 39 the lining, is cut off from the stock and is lost. A good fire-brick lining should last from one to two years, according to the amount of iron melted and the way the lining is daubed and kept up. There is nothing gained by keeping a lining in too long, as it will be- come shaky, and the blast pass up through and behind it instead of passing through the stock, and more fuel is required to make hot iron. FIRE-BRICK. For lining cupolas and furnaces, the selection of a proper description of fire-brick is a matter of consider- able importance, and the foundryman should be careful to select the best brick regardless of expense, for a few dollars more on the thousand is nothing when compared with the consequences of using cheap and inferior brick, which would be costly at any price. From the great w^ear and tear upon them, and from the delay and loss caused by the often-repeated stoppages for repairs, it is the wisest and the best economy to always use the best fire-brick that can be procured. I shall not enter into the merits of the fire-brick manufactured by different companies, but I should recommend the use of the white or softest brick as being the best for standing the fire ; and in lining up a cupola, the softest brick should always be selected for the bottom, where the heat is greatest, and the hard ones for the top, where the lining is liable to be struck and broken by throwing in the iron and fuel. The wedge or circular brick is better for lining cupolas than the straight brick, as they can be laid closer together and require less mortar, and will make a better and more solid lining that will last longer. 40 FOUNDING OF IRON. TUYERES. The tuyeres in a cupola should be put in at equal distances apart, and they should be arranged so that each one of them will admit an equal amount of blast into the cupola. A tuyere should never be put into a cupola directly over the tapping hole, and if the tuyere- is a continuous one, as is the McKenzie, it should be^ stopped up over the tapping hole. The height of the tuyeres from the sand bottom will vary according to the class of work that the cupola is intended for. In stove foundries, where the iron is drawn out as fast as- it is melted, the tuyeres are put in very low ; but in a machinery foundry, where it is desirable to hold the molten iron in the cupola for a large casting, the tuyeres are put in higher ; but the low tuyeres are the best for making hot iron and for continuous melting. In all of our large stove-foundry cupolas the tuyeres are put in only two or three inches above the sand bottom, and in some of them the tuyeres are so low that the sand bot- tom is slopped clear up to the bottom of the tuyere. When the tuyeres are put in low, the melting point of the cupola is lower, and less fuel is required for the bed^ and the bed is easier to keep up in a long, continuous heat. The tuyeres should never be put in more than ten or twelve inches above the sand bottom, for the cupola will not make as hot iron, and it is almost impos- sible to keep the bed up for a long, continuous heat. The old style of having one tuyere hole above another, and raising the tuyere pipes as the cupola fills up with molten iron, and stopping up the lower tuyere holes with clay, has generally been abandoned as a failure ; for, after the cupola has been filled up with molten iron in this way, and the iron drawn out, the stock will gen- erally settle so that the cupola is of no account for fur- ther melting; and for a long, continuous heat it is better to draw out the iron as fast as it is melted, and FOUNDING OF IRON. 41 hold it in a ladle, if necessary. I should recommend low tuyeres in all cases for making hot iron and saving fuel. The foundryman must use his own judgment as to how many tuyeres to put into his cupola, but he should put in enough to distribute the blast equally through the stock, and no cupola should have less than two tuyeres or one continuous one. Fig. 1. DIFFERENT SHAPED TUYERES. There are a great many different shaped tuyeres or openings in the lining for admitting the blast into the cupola, and I will now describe some of the principal ones in use that give good satisfaction. The oldest tuyere in use is the common round tuyere, and it gives good satisfaction when put in right. The tuyere (fig. 1) is a cast-iron frame, with a slot or opening in it two inches wide, by ten or twelve inches long. This tuyere was in use in Davis' stove foundry in Cin- cinnati, Ohio, in 1874, and gave good satisfac- tion. The T shaped tuyere (fig. 2) is a cast-iron frame, with a slot or opening at the bottom two inches wide by eight inches long, with an up- right slot two inches wide by ten or twelve inches long. This tuyere was in use in the stove foundry of Headway & Burton, in Cincinnati, Ohio, in 1875, and appeared to give good satisfaction. The tuyere (fig. 3) is a slot one inch wide, running one-third of the way around the cupola on each side, with four upright slots, each one inch wide and ten or twelve inches high. This tuyere may be made as a Fig. 2. 42 lOUNDlNG OF IRON. cast-iron frame, or be formed in the brick lining; it was in use in the foundry of Griffith & Wedg, Zanes- ville, Ohio, in 1873, and gave good satisfaction. A ri(i. cupola forty inches in diameter, with two of these tuyeres in, would melt five tons of iron per hour. The tuyere (fig. 4) is a slot tuyere one inch or more wide, and running one-third of the way around the cupola on each side ; or it may be connected and form a continuous tuyere all around the cupola. These tuy- eres are made by taking two iron plates and laying small blocks of iron between them, as shown in fig. 4. [ JZZ ] Fig. 4. This tuyere was in use in a hollow-ware foundry in Allegany City, in 1874, and appeared to give good sat- isfaction. The tuyere (fig. 5) represents a tuyere that is in use in some of the foundries in Philadelphia and New York. It is said to give good satisfaction. The ti^yere (fig. 6) is an oval shaped cast-iron tuyere ; Ait is generally laid flat, as shown in fig. 6, and is made large or small, to suit the size of the cupola. This tuyere is in general use in the Troy and Albany stove foundries, and is said to be a good tuyere. \ / The tuyere (fig. 7) is the Lawrence patent V reducing tuyere. This tuyere is made of cast- FiG. 5. YVQYi^ and is a cast-iron frame with a large opening at the bottom, and an upright slot, reduced to FOUNDING OF IRON. 43 nothing, at the top. The large opening is about three inches in diameter, and the slot is ten or twelve inches long. This slot is one inch wide at the bottom, and tapers to nothing at the top. This tuyere gives good satisfaction when it is in proper shape ; but the upright slot is liable to collapse from the heat, as it is too small to admit enough blast to keep it cool. This tuyere would do better if it was made of fire-clay. The tuyere (tig. 8) is a reducing tuyere, and is merely one round opening above another. They are put in two or more inches apart, and three or more may be put in, CD o o A Fig. 6. Fig. 7. Fig. 8. Fig. 9. ill a row, and each one gets smaller towards the top. This tuyere is used in the Truesdale patent cupola ; but I do not know whether Mr. Truesdale has a patent on the tuyere or not. The tuyere (fig. 9) represents a triangle-shaped tuyere that is used in some of the Cincinnati foundries ; it is a cast-iron frame, set in the brick lining, and may be made as an equal triangle, or it may be a little higher than it is wide, so as to bring it up to a sharp point at the top. I think this a good tuyere, for the sharp point at the top cuts the blast at the top, and it is not so liable to form a bridge over the tuyere as the round or oval-shaped tuyere is ; and I should recommend this tuyere in preference to all others, especially for small cupolas. 44 FOUNDING OF IRON. CAPACITY OF CUPOLAS. There are so many things that control or affect the working of a cupola, and the melting of iron, that it is almost impossible to make any estimate of the size that a cupola should be to melt any given amount of iron. The shape of the cupola, the size and number o*f tuyeres, the pressure of blast, the height and draft of the cupola, the way in which the cupola is daubed and made up, the way the bed is burnt and the stock is charged, and the kind of iron melted, all make a difference in the melting capacity of a cupola. From practical observa- tions in melting with both coal and coke, I have made out the following table as an approximate of melting capacity, for the guidance of foundrymen who may wish to put up new cupolas. S o.a east amount should be melted. ay be melt- d with ease. ay be melt- ed by care- ful charg- ing. o" j Exti-eme melt- ? 1 ing capacity. 3J u ft ^ 02 h; g« S H ton. ton. ton. 15 6 to 8 15x18 1 H 2 I 20 8 to JO 20x24 1 2 3 4 1 24 9 to 10 24x28 2 3 5 6 1 1 30 10 to 12 28x30 3 5 8 10 3 40 11 to 13 28x30 5 9 13 16 5 50 12 to 14 30x36 8 14 20 23 7 60 13 to 15 40x30 11 16 22 25 8 Note — The pressure of blast depends upon the volume of blast. The above table of melting capacity is only intended for the common straight cupola. The diameters given are the diameters inside of the lining. A cupola should never be made less than fifteen inches in diameter ; for the stock will hang, and the cupola will bung up very easily, and will be more bother than it is worth. If a FOUNDING OF IRON. 45 cupola is over sixty inches in diameter it should be drawn in at the tuyeres, as the McKenzie and Law- rence cupolas are, so as to throw the blast to the centre of the stock. I do not consider the melting capacity of a cupola to be the largest amount of iron that can pos- sibly be forced through it in any shape, but the amount that can be melted with ease, and the cupola left in good shape when dumped. HIGH AND LOW CUPOLAS. From the bottom plate to the bottom of the charging- door is the height of the cupola, and the top of the charging-door is the bottom of the stack. It is claimed by some of the theory-melters that five feet is too great a height for a cupola, and that the best and most eco- nomical melting can be done in a cupola of three or four feet in height ; they claim that there is no other advantage in having a high cupola than having a large body of fuel on fire at once ; this they claim may be effected to more advantage by a greater diameter, and that the low cupolas, even as low as three feet, do bet- ter melting than high ones. This theory may be very good for small cupolas, where it is only desirable to run off a heat of a few hundred of iron, but it will not do where it is desirable to run off* a large heat in a few hours and make hot iron. Just imagine some of our large stove foundries, that melt as high as twenty tons of iron in one cupola, melting that amount of iron in a cupola only three feet high ; it would be utterly impos- sible to run off a heat in any reasonable length of time, or to make hot iron. If we increase the diameter of the cupola too much, the blast cannot be forced into the centre of the stock, so that we cannot gain the same advantages that we could by increasing the height of 46 FOUNDING OF IRON. the cupola ; yet I think this theory of low cupolas and large diameters is the correct theory for building small cupolas ; for, if we build a cupola of a very small diam- eter and great height, the stock is liable to hang on the lining, and we cannot force it down ; but if the cupola is low and of a large diameter, it- will not be so liable to hang, and if it does hang, we can poke it down with a bar ; and I think that a cupola with a small diameter should be low, and its height increased as the diameter is increased. I have found, by accurate comparative tests in melting with coal and coke, that high cupolas do faster and more economical melting than low ones, because more stock can be put into them at once, and it will be getting hot from the heat that otherwise would escape up the stack ; the iron will be hot and in a better condition to melt when it comes down to the melting point, and it will make a softer iron ; there will be more of a downward pressure, and the blast will be more confined, and the heat concentrated If the cupola is low, we cannot put so much stock into it at once, and there will be less of a downward pressure ; the blast will not be confined, but will pass through the stock, carrying with it a great deal of unconsumed gases, and more fuel and more time will be required to make hot iron. I found, by careful tests made in Philadelphia, Pa., in 1874, that a cupola forty-five inches in diameter and fourteen feet high, would melt as much iron in an hour (with one per cent, less coal), arid would run off as large a heat as a cupola sixty inches in diameter and ten feet high, with the same pressure of blast. I found by careful tests made in St. Louis, Mo., in 1875, that a cupola fifty inches in diameter and thir- teen and a half feet high, would melt fifteen tons of iron (with one per cent, less coke), in the same time that a cupola fifty inches in diameter and nine feet high would melt ten tons of iron with the same pressure of FOUNDING OF IRON, . 47 blast. The above tests were not made in any one foun- dry, but were comparative tests between one foundry and another, and go to show why one foundry can sell castings cheaper than another. T should recommend high cupolas in all cases where the diameter is large, and more especially where coal is used for fuel in melting ; for coal will break and spall off when suddenly heated. This fine coal or spall will settle down through the stock (especially if the coal used in melting is large), and is not burnt, but will set- tle down and lay over the tuyres, an will gather cinder and prevent the cupola from melting ; and when the cupola is picked out, thesie small pieces of coal will be found mixed with the cinder, appearing as if they never had been touched by the fire. It is impossible to en- tirely overcome this mechanical destruction of the coal, but it may be overcome to a certain extent by high cupolas ; for, if the cupola is high, more stock can be put into it at once, and the coal will be heated up grad- ually and will not be so liable to crack and fly from the heat. On the other hand, if the cupola is low, very little stock can be put into it at once, and after the blast is on for a short time, the stock becomes hot clear up to the charging-door, and the next charge of coal is struck by an intense heat as soon as it is thrown in, and it cracks and flies, and we have a mechanical destruction of the coal in place of a chemical combustion. While I would recommend high cupolas for melting iron with coal, I would also caution the foundryman against too great a height, for we may get a cupola so high, that throwing in the iron will damage the coal more than heating it suddenly would do. A few plates should always be put in on top of the coal, to protect it from being broken up by throwing in the heavy iron. 48 FOUNDING OF IRON. Mckenzie cupola. Fig. 10 represents a sectional view of the McKenzie patent cupola. This cupola is generally made oval in form instead of round; the lining is contracted just above the tuyeres, and is supported by an apron bolted on to the caisson. This apron projects inward and forms an opening or air chamber all around the cupola, as indicated by B B. This air chamber is supplied with air from the blast pipes, D D ; the tuyere is a con- tinuous one, and is merely an open slot, about two inches wide, running all the way around the cupola, as represented by the letters AAA. This tuyere is sup- plied with blast from the air chamber, B B. This cupola is in use in a great many foundries, especially in stove-plate foundries, and it will do very good melt- ing when kept in proper shape, as shown in Fig. 10, but is very liable to get bridged out or collect cinder over the tuyere ; and if the melter does not keep the cinder chipped off, it will soon get the lining in the shape shown in Fig. 11, which shape will reduce the melting capacity of the cupola and cause it to bridge over in a short time. To avoid this, the melter should be careful to keep the lining in as near the shape shown in Fig-. 10, as possible. Small cupolas, constructed on the McKenzie plan, are generally a failure on account of bridging over above the tuyere, and even the large ones have in some cases been condemned on that ac- count ; but the large McKenzie cupolas will work well, if kept in proper shape, but where this style of cupola will not work well, the apron can be taken out and the cupola made into a common straight one. I have seen one of these cupolas at the Greenwood Stove Works, in Cincinnati, Ohio, out of which the apron had been taken and six round tuyeres put in,- one at each end and two on each side at equal distances apart ; this arrangement worked better in this shop than the apron and continu- ous tuyere. Pig. 10. Fig. 11. Fig. 12. FOUNDING OF IRON. 49 RETURN-FLUE CUPOLA. The return-flue cupola, Fig. 12, was arranged and erected by Mr. John O'Keefe, superintendent of Perry & Co.'s Stove Works at Albany, N. Y., with a view of saving fuel and catching the sparks from the cupola. With this view, the arch A was built across the cupola just above the charging-door, so as to throw^ the heat down upon the iron, and the flue B was led out of the cupola just under the arch A, and brought down to the floor and returned to the cupola above the arch, and when the cupola was in operation all the waste heat from the fuel passed up and struck the arch A, and was again thrown* down on the iron or forced through the flue B, as indicated by the black dart. At the bottom of this flue it turned as indicated by the white dart, and passed up the flue C, and again entered the cupola above the 'arch A. As the flame passed down the flue B, and turned to pass up the flue (7, all the cinders and sparks were deposited at the bottom of the flues, and were removed through the door or opening D as often as it became necessary. This cupola was a success so far as the catching of the sparks was concerned, but little or no fuel was saved by it ; for, after the arch had been put in, the cupola threw the flame out at the charging-door when the blast was on, so that it was im- possible to charge the stock, and it became necessary to make a small opening through the top of the arch J., so as to admit of the escape of part of the flame. Had this cupola been high enough, so that all the stock for the heat could have been charged before the blast was put on, and the charging-door closed up tight, there is no doubt but what considerable fuel would have been saved by this arrangement. Several diff'erent kinds of spark-catchers have been used for cupolas, but this one is the best I have seen in use. A cheap spark-catcher 4 50 FOUNDING OF IRON. for a cupola can be arranged by taking a round cast- iron plate nearly as large in diameter as the diameter of the stack, and hanging this plate in the stack near the top of it ; the sparks go up and strike the plate, and are again thrown down into the cupola. This j^late will be burnt up in the course of time, and must be re- placed by a new one ; but when a cupola is constructed as shown in Fig. 13, no spark-catcher is needed. STRAIG-HT CUPOLAS. I have seen and melted iron in almost all of the odd- shaped cupolas that are in use at the present time, but I have not found any of them superior to the common straight cupola, either for fast melting or for economy. It is true that some of these cupolas require a little less fuel for the bed than the straight cupola does; but what is saved in the bed has to be added to the charges in a large heat, so that nothing is saved in the long run. Yet to do good melting, either in an odd-shaped cupola or a straight one, the lining must be kept in proper shape. In fig. 13, I have represented my idea of a perfect cupola for melting iron. In this illustration I have shown how the bottom plate should project inside of the lining in a large cupola, so as to make the bottom doors smaller and easier to handle. I have shown how the lining should be sloped out to the edge of the bottom plate, so that the sand bottom will all fall out when the iron bottom is dropped. This offset also helps to sup- port the stock, and takes part of the weight off of the iron bottom. The caisson or shell of a cupola will often rust off, and give way around the bottom. This is caused by the lining sweating, and the moisture settling to the bottom, and by putting in a heavy sand bottom, C)U»^U.Ut.LBnJUl» Fig. 13. FOUNDING OF IRON. 51 and providing no way for the moisture in the sand to escape ; this moisture keeps the lower courses of brick always damp, and causes the caisson to rust off in a short time. I have shown in this illustration how this may be avoided by laying the first two courses of brick out one or two inches from the caisson, so as to form a small air-chamber all around the cupola, as represented by the letters A A. Small holes should be put in around the bottom of the caisson, or through the bottom plate, to supply this chamber with fresh air, and allow the moisture to escape. In this illustration, I have shown a triangular-shaped tuyere ; this shaped tuyere, I think, is the best in use, especially for a small cupola; for it comes up to a sharp point at the top, and is not near so liable to bridge over as the round or oval-shaped tuyere. I have shown a hollow place in the lining of this cupola, just above the tuyeres, which indicates the melting point of the cupola. If a cupola is lined up straight, it will burn out hollow at this point in one or two heats ; and in daubing up the cupola for a heat, it should never be daubed up straight or too full at this point, but should be left a little hollow, as shown in fig. 13. I have shown how brackets or angle iron should be riveted on to the caisson every three or four feet, so as to support the lining, and admit of the lower part, where the lining burns out the fastest, being taken out and replaced without taking down the whole lining. The lining can be taken out and replaced without the brackets by taking out one side of it at a time, and re- placing it with the new lining before taking out the other side ; but after a lining has been taken out and replaced in this way it always settles, and cracks, and injures the lining. I have shown how the stack should be reduced to one-half or less the diameter of the cupola, and how it should be drawn in by an arch just above the charging door. I think that a cupola con- tracted suddenly, as this one is, is better than to have 52 FOUNDING OF IRON. a long-tapered contraction, for in this cupola the heat conies up and strikes the arch, and is thrown down on the iron; The sparks strike this arch, and are not so liable to be carried out at the top of the stack as in a long contraction by reducing the diameter of the stack. In this way the heat is more confined and equalized, and will make a more even iron than a cupola with a large stack, where the heat escapes freely up the stack. DAUBINa THE CUPOLA. The most important thing in the melting of iron in cupolas is the proper construction of the cupola ; and the next important thing is to keep the lining in proper shape. I have shown, in fig. 13, what is the proper shape, — which is a slight projection over each tuyere, to prevent the iron from dropping into the tuyere, and a hollow in the lining, or increased diameter of the cupola just above the tuyeres. This hollow place in the lining may be a little higher than I have shown in this illus- tration, as explained under the head of " The Melting Point ;" but in putting in a new lining, it is not neces- sary to form this hollow in the lining, for the heat will soon cut it out at the melting point ; and in daubing and making up the cupola for a heat, the lining should always be left slightly hollow at this point, as shown in fig. 18. Some melters, who do not thoroughly understand their business, think that, when the lining burns out hollow at the melting point, they must make it up straight with daubing, or the lining will burn through, and the iron will run out through the caisson ; and they will daub on a belt of mud two or three inches thick all around the cupola, as shown in the sectional view of a ;^V-i\.UK\.B,l«», Fig. 14. FOUNDING OF IRON. 53 cupola (fig. 14). This belt of mud is not only made flush with the lining, but it often projects out farther than the lining, and by it the diameter of the cupola is decreased at the point where it should be the largest. The daubing for cupolas is generally made of common clay, mixed with a little fire-sand or sharp-sand. This daubing will not resist the heat like fire-brick or fire- clay, and the heat is more intense at this point than at any other in the cupola ; and this daubing, if put on too thick, will melt and be converted into a cinder or slag ; and this slag will run down and be chilled over the tuyeres by the cold blast, and will bung up the cupola in a short time ; or this mud belt may break loose from the lining, as shown in fig. 15, which illus- tration represents a sectional view of the interior of a cupola that I saw at Richmond, Indiana, in 1875. This cupola was about thirty or thirty-five inches in diame- ter, and the average heat melted in it was about four tons ; the melter, in charging, used too much coke in the bed and between the charges of iron. This caused slow melting, which was very hard on the lining, and cut it out badly at the melting point ; and when chip- ping out, and making up the cupola, the melter would chip out all the cinders and slag until he came to the brick, and in knocking ofi" the cinders he would jar and crumble the face of the brick ; he would then daub on a belt of mud two or three inches thick all around the cupola, as shown in fig. 14. This mud was too heavy to hang on the brick, and when it was heated slowly the moisture was all forced back against the brick lining, which moistened the mud at that point, and caused it to break away from the lining ; and it would then settle down in a heap over the tuyere, as shown in fig. 11 ; but when it was heated rapidly, the heat would bake the outside of it and prevent it from squat- ting down in a heap. The moisture in the mud was converted into steam, and was forced back against the 54 FOUNDING OF IRON. brick, where it would be partially condensed ; and the water would soften the mud, and the steam would force it off from the lining at the top, and the fuel and iron would get down behind the mud and force it down into the cupola, so as to bridge it over above the tuyeres. One day, while I was at this foundry, the cupola melted very slow, and when the heat was about half off the iron began to run out at one tuyere, and no iron at all could be gotten out at the tap-hole. The cupola con- tinued to melt in this way for a short time and then stopped altogether; and the bottom was dropped. On examining this cupola the next morning, I found it to be in the shape shown in fig. 15. The belt of mud had broken loose at the top from the brick lining, and the fuel and iron had gotten down behind it, and forced it down into the cupola, so that it formed a complete bridge over it just above the tuyeres, with only a small opening in the centre; All the fuel around this open- ing had been consumed, and the iron came down and. lodged on this bridge of mud; and it was here struck by the cold blast, and the melting stopped. On the one side the bottom of this mud belt still hung to the lining, but on the other side it had broken loose alto- gether, and had sank down below the top of the tuyere and on this side some little iron had been melted above the mud bridge, and came down and run out at the tuyere. This melter always had trouble in dumping his cupola, and he generally had to poke and pry at it with a bar for one or two hours every heat before he could get it down ; and sometimes he would have to work at it until eight or nine o'clock at night. All his trouble was caused by too much daubing. The lining would be cut in holes every heat, and the melter had to put in a few new brick after each heat. All these holes that were cut in the lining were caused by using too much daubing, and the daubing breaking loose from the lining and settling down in such a shape as to Fig. 15. FOUNDING OF IRON. 55 throw the blast and heat against the lining in spots, instead of having an equal heat all around. This cupola had to have about two or three feet of new lining put in, just above the tuyeres, every two weeks, and the melter, to protect this new lining, would always daub an inch or two of mud upon it ; this mud, instead of protecting the lining, was the cause of its burning out, for it would break loose from the new lining and settle down so as to prevent the free work- ing of the cupola, and concentrate the heat upon the lining and melt it down instead of melting the iron. The melter in this foundry had made the propri- etor believe that the cupola was too small to melt four tons of iron, and that it was worn out, which was the cause of all his trouble with it, when really the whole trouble was, that the melter did not understand his business, and his ignorance was costing him a great deal of extra labor and costing the foundry com- pany five dollars or more every day for extra fuel, fire- brick and clay. Yet the lining of a cupola will be burnt out at the melting point a little every heat, and If the melter does not replace it, it will burn through to the caisson and the iron will run out through it. To prevent this, the melter must have recourse to daubing, but he should be careful not to use too much or too little daubing, and he should keep between the two ex- tremes, and to do this, he should not daub on more than a half inch or an inch of daubing at any one place, and if this amount of daubing will not keep up the lining, it cannot be kept up by putting on more than that amount ; for after he gets beyond that amount, the daubing is too heavy to hang on to the lining, and it breaks loose and does more harm than good ; even one inch of daubing is too much to put on all around the cupola. When chipping out the cupola, the melter should not chip out all the cinder until he comes to the fire-brick, but he should merely chip out enough to get the cupola in 5fi FOUNDING OF IRON. proper shape ; for this cinder has been oxidized by the heat, and in many cases it will stand the fire better than the new daubing. If a cupola cannot be kept up by putting on a small amount of daubing, then there is something wrong, and the melter should at once find out what the trouble is, which may be in his manner of charging in the tuyeres, or in the blast : for if the iron is charged high in the centre it will throw all the fuel to the outside, and will cut the lining worse than when charged level ; and if the stock is charged uneven, it may be the cause of cutting out the lining in holes ; if the blast is too sharp and cutting, it will be hard on the lining ; if the tuyeres are not put in at regular distances apart, they may cut the lining badly by throwing the blast and heat against the lining in spots. When the melter finds his lining hard to keep up, he should regu- late his mode of charging; if that does not do any good, then he should vary the blast ; if that does no good, then he should change the shape, size or place of the tuyeres. SWIVEL CUPOLA. The swivel cupola, fig. 16, is a very handy little cupola for small work, and is in use in a great many small foundries. In constructing this cupola, four iron columns are used to support the stack, which is set upon an iron plate on top of the columns. The stack may be made of boiler plate and lined with fire-brick, as shown in fig. 16, or it may be built of common brick ; two cross-bars are bolted on to the columns, and the cupola is hung on two swivels, which rest on the cross- bars ; the top of the cupola does not touch the plate upon which the stack stands, but is two or three inches below it, or low enough to allow the cupola to be turned over without striking the plate. This cupola may have Fig. 16. FOUNDING OF IRON. 57 a drop bottom or a stationary bottom with a brick hearth. When the bottom is stationary, the refuse may be drawn out at the front, or the cupola may be turned upside down and dumped. When the cupola is only fifteen inches or less in diameter, the stationary bottom is the best ; but when the cupola is over fifteen inches in diameter, the drop bottom is to be preferred. When the drop bottom is used for this cupola, it should be supported by a latch or cross-bar, and not by a prop, for the cupola may be rocked a little when charging the stock, and the prop will give way. The swivels or bearings should be bolted on to the cupola a little be- low^ the centre, so as to have the cupola as nearly bal- anced as possible when the iron bottom is on, so that the cupola will be easy to turn on the swivels. This cupola may be turned over by hand or by gear-wheels attached to the swivels. When the cupola is large, or where it is desirable to dump the refuse by turning the cupola up- side down when hot, the gear wheels should be used. As only a small amount of iron is melted in this cupola at a time, a two-inch lining is heavy enough for it. When picking out and making up the cupola for a heat, it may be laid over on its side and picked out with a long bar to avoid going into it. When it is desirable to melt more iron than the cupola is capable of melting, it may be run until bunged up, and then turned over and dumped, and picked out with a long bar while hot, and then turned up and fresh stock put in and the heat continued. This style of cupola should not be made more than twenty inches in diameter and six or seven feet high, as it would be too heavy to handle when lined. The swivel cupola is a very handy and conven- ient little one for melting small quantities of iron, and for mixing irons to test their quality, and no large foun- dry should be without one. Most of our large foundry- men have no small cupolas in their foundries, and when introducing new brands of iron they have to test their 58 FOUNDING OF IRON. qualities in the large cupolas, and through an entire heat, and in this way whole heats of castings are often lost, which loss "might have been avoided by having a small swivel cupola and testing the quality of the iron on a small scale, before introducing it into the large cupola or through the entire heat. THE SAND BOTTOM. Sand gathered from the gangway is generally used for the bottom ; a little new sand is sometimes added to give it more strength. All new sand, sharp or fire- sand, should never be used for the bottom (especially in small cupolas), for it will bake in too hard and not droj) easily. Some melters prefer to gather the old bot- tom out of the pit and add a little new sand to it, and put it in again. This makes a very good bottom, as the sand from the old bottom will contain small parti- cles of cinderj which will make it open and porous and prevent it from baking in hard, and make it drop easily. The old bottom should always be put into a small cupola in preference to sand from the gangway ; the sand bot- tom should be put in so as to be high around the outside and have a gradual slope towards the centre and front. Care must be taken to not give it too much slope, as it will throw the iron out with too much force when tapped ; care must klso be taken to not get the bottom too flat, or the iron will not run out and will chill on the bottom and make dull iron. The thickness of the sand bottom will vary from two to ten inches, according to the size of the cupola. If the sand bottom is too wet it will make the first iron hard ; if it is not rammed even and packed solid around the edges, it may allow the iron to run out ; if it is rammed too hard the molten iron w^ill not lay upon it, but will boil and cut up the sand, and make a dirty iron, and it may cut through the sand and run out through the iron bottom. FOUNDING OF IRON. 59 FRONT OR BREAST. The front should be put in with sand or loam that will not bake in too hard, and will not cut nor crumble when the iron strikes it. A little fire-clay is sometimes used in the bottom of the spout and around the tap- ping hole, to prevent the tapping hole from cutting out and getting too large. The front should not be more than one and a half inches thick at the tapping hole, or the iron will be liable to chill in the tapping hole between taps. When the lining of the cupola is very- thick, the brick should be cut away around the front on the inside, so as not to have the sand front too thick. 8ome melters put in their front before the fire is lit ; this answers very well when the cupola is large and the tuyeres are low down, but it will not do in a small cupola with high tuyeres. Coke melters build up a wall of coke in front of the fire and ram the sand against it ; this makes a very good front. Some coal melters cut a piece of board the proper size, with a notch in the bot- tom of it, and set the board back against the hot coals, and ram the sand against the board ; this makes a very nice front, for the board soon burns out and dries the front, and leaves it straight and even on the inside. Most melters ram the sand back against the hot coals, and pay no attention to the inside of the front ; this should never be done, for the front will be rough and uneven on the inside, and will cut and crumble with the heat and iron. This way of putting in the front is often the cause of dirty iron and of slag running out at the tapping hole. TWO FRONTS OR BREASTS. In some of the large stove foundries in Troy and Albany, N. Y., two fronts are put in their large cupolas. They are both put in on one side of the cupola, about 60 FOUNDING OF IRON. ten or fifteen inches apart. This is done for safety. They are tapped turn-about, and it is claimed that the tapping hole can be kept in better order, and in case one tapping hole gets in a bad shape, it can be stopped up altogether and the other one used. I think that putting in two fronts in this way only makes more work for the cupola-tenders, and more expense for loam or sand, without gaining anything ; for the tapping hole will never get in a bad shape if the front is put in right and is tapped right ; and if it does get in a bad shape, it is an easy matter to stop the blast a few minutes and fix it or put in a new front. In the foundry of James L. Haven & Co., in Cincinnati, Ohio, two fronts are put in their large cupola, one on each side ; this is done for convenience in carrying away the iron, and not for fear of the tapping hole giving out, or on account of fast melting. THE SPOUT. The spout may be made up with the same kind of sand or loam as the front or breast is put in with. It is a good idea to paint the spout with a little blacking mixed with water ; this prevents the iron from sticking to the sides of the spout. The spout may be dried by the flame blowing out at the tapping hole before the iron comes down. If an iron plate is laid on top of the spout while the flame is blowing out, the heat will be more confined and the spout more thoroughly dried. Building a big wood fire on top of the spout to dry it, is an old-fogy idea, and the man that invented it died a long time ago. STOPPING- BODS. Molding sand, mixed with a little clay-wash, makes a very good bod that is easily tapped out. When fire- clay, or other heavy clay, is used for bods, a little FOUNDING OF IRON. 61 blacking or sawdust should be mixed with it, so as to make it tap easily. The blacking or sawdust will soon burn out and leave the bod porous, and it can be easily cut away. The first bod for stopping in with should be sharp-pointed, so that it can be shoved well back in the hole, to prevent the iron chilling in the hole before the front has been thoroughly warmed up. After the front and bottom have been thoroughly warmed, the bod should be made round, so as not to shove it back into the hole too far, and to make it tap easily. Care should be taken to have the bod-clay thoroughly mixed, and not too wet nor dry. Tappers often lose their eyes or get badly burnt by the careless way in which they mix and handle their stopping bods. STOPPING- OB BOD STICKS. . The tapper should have at least three bod sticks — one good large one — always ready in case of accident. Bod sticks are generally made of all wood ; but some prefer an iron rod, from six to twenty inches long, with a button on one end and a long wooden handle on the other. This makes a good bod stick, where a long spout is used ; for the iron rod will not burn away, as the wood will do from the heat in the spout. A bod stick made in this way may be used for years. TAPPING- BARS. The tapper should have at least three tapping bars ; one a one-half inch, one a three-fourths inch, and one an inch in diameter. They should be long enough, so that the tapper can stand back from the cupola, and not be in danger of getting burnt every time he taps 62 FOUNDING 0I< IRON. ^ out. The bars should be drawn down to a long square point, so that the bod can be cut away by turning the bar, and leave a nice, smooth, clean hole. If the tap- ping bar is round and blunt on the end, the bod will be shoved into the cupola, and the molten iron, running out, will force it back into the hole, and prevent the iron from running out freely. LIG-HTING- THE FIRE. Too much care cannot be taken in starting the fire in the cupola ; for the fire in the bottom of the cupola is the foundation upon w^hich the iron is melted. The theory of starting the fire in any shape, and depending upon the blast to equalize it, is wrong. My experience is, a poor fire on the start makes poor iron all through the heat. The wood to light the coal or coke with should be cut in lengths of from ten to eighteen inches; and two or three rows of wood should be set upon end around the sides of the cupola, so as to protect the dob- bing- and 2:ive the fire vent. The centre should be filled in with short wood, so arranged as to give the fire the best possible chance to burn. The w;ood, when all in, should be level and even on top. When the wood is cut short, and put in the cupola in this way, one-third less will be required, and the coal or coke will be lit more even, and better melting can be done than when the wood is put in long and uneven. Gas-house coke is sometimes used wuth wood for starting the fire w^hen coal is used for melting; this is done for economy. Less wood is required when the gas-house coke is used, and the coke is often cheaper than the wood. Some melters put their wood into the cupola in the regular cord-wood lengths, and throw it in in any shape. The coke or coal is put in, and will roll down through the FOUNDING OF IRON. 63 wood and lay on the bottom ; the fire is lit, and the wood is all burnt out, and the coke or coal is only lit in spots, and probably there will be a pile of coke or coal lay on the sand bottom under the tuyeres that is not lit at all until the iron is melted and runs through it. This careless way of starting the fire is often the cause of dull iron and slow melting. CHARG-ING WITH COAL. After the wood has been put into the cupola in the proper shape, the coal for the bed should all be put in before the fire is lit, except a few pieces to level up with after the wood is all consumed and the coal al- lowed to settle. After the wood has all burnt out and the bed has settled, the top of the bed, when all in, should not be more than twelve or fourteen inches above the top of the tuyeres. No regular time can be set for charging the iron, for the cupola will have a better draft on one day than another ; and care must be taken not to get the bed burnt too much before the iron is charged. When the wood is entirely consumed, and the bed has settled and burnt through, so that the fire can be seen on the top of the bed, it is time to charge the iron. A few plates or other light scraps should be put in on the coal, to prevent it from being broken up by throwing in the heavy iron, and to prevent it from settling down into the bed, as it will do if the coal used for melting is small. The pig-iron should be charged with the face or top of the pig down, and the ends out towards the lining, as it will melt better than if charged with the side of the pig flat up against the lining, with the coal only on one side of it ; it should be charged as compactly together as possible, so as to utilize all the heat from the coal, and not allow it to escape up the 64 • FOUNDING OF IRON. stack. Each charge of iron should be level on top, and not high in the centre, as it will throw the coal and heat to the outside, and will cut the lining of the cupola more than if charged level ; it should be charged in as large charges as the cupola will melt, so as to have a good bed of coal between the charges of iron, without using too much coal. The iron should be charged in the cupola from two to three hours before the blast is put on. The bed should never be allowed to get white hot on top before the iron is charged. If the bed is burnt too much the iron will be dull through the first charge, and probably through the entire heat. If the bed is too high, or is not burnt enough, the iron will be a long time in coming down, and the cupola may melt slow through the entire heat. If too much coal is used be- tween the charges of iron the cupola will melt irreg- ularly. The iron should be down in five or ten minutes after the blast is on if the cupola has been charged right. The charging door should always be closed after the stock is all charged. COAL MELTERS. When melters, who have been accustomed to melting with coal, undertake to melt with coke in the same cupola, they should remember that their cupola has more draft than a regular coke cupola ; that less wood is required to light coke than coal. Coke will burn up faster. The bed must be put in higher up. The iron should not be melted in as large charges. The coke should be charged by weight, and not by bulk ; it will melt iron faster than coal, and care must be taken to keep it out of the tuyeres. FOUNDING OF IRON. 65 CHARGING- WITH COKE. Less wood is required for starting the fire when coke is used for melting than when coal is used. If the cu- pola has a good draft, all the coke for the bed should be put in on the wood before the fire is lit ; but if it has a poor draft, only part of it should be put in before light- ing the fire. When the wood has burnt out and the €oke is red hot at the tuyeres, it is time to charge the iron. A coke bed should never be allowed to get red hot on top before the iron is charged. The top of the bed, when all in, should not be more than eighteen or twenty inches above the top of the tuyeres when the iron is charged. The iron should be charged from one to two hours before the blast is put on ; it should not be melted in as large charges with coke as with coal. In other respects, the same directions should be followed as given in charging with coal, and the same results will be produced from improper charging. COKE MELTERS. When melters, who have been accustomed to melting with coke, undertake to melt with hard coal in the same cupola, they should remember that their cupola has not so much draft as a cupola built fqr melting with coal. More wood must be used to start the fire ; and it must be lit earlier. The bed must not be so high. The iron must be charged in larger charges. The coal should be charged by weight, and not by bulk. Coal will melt iron slower than coke. 66 • FOUNDING OF IRON. PIG-IRON. All pig-iron has more or less sand on it, and has a hard, chilled scale under the sand, which resists the action of the heat upon the iron, and prevents its melt- ing. If the pig is broken before it is charged, it ex- poses the clean iron in the ends of the pig to the heat, and it will be noticed that the pieces of pig dropped through, partially melted, have commenced to melt at the ends where the clean iron was exposed to the heat. Pieces of pig will sometimes be found where their ends have been melted out for an inch or more, and left the outside scale on the pig standing, which shows that this scale resists the action of the heat upon the iron ; and the shorter the iron is broken, the more clean ends will be exposed to the heat, and the better it will melt, and less fuel will be required to melt it. A pig should be broken in at least three or four pieces before being charged. In charging the cupola the pig-iron should be thrown in with the face or top side of the pig down, as it has less scale on the top than on the sides, and will melt better. All these little points are taken ad- vantage of by the practical and scientific melter. PRESSUBE OF BLAST. The blast should be put on light at first ; not more than one-half of the pressure should be put on for the first five or ten minutes. The pressure of blast used for melting iron in cupolas will vary from six to sixteen ounces, the best melting being done with from eight to ten ounces pressure with coke, and with from ten to fourteen ounces pressure with coal. The foundryman or melter should use his own judgment about the blast, and he should know by practical experience when he FOUNDING OF IRON, 67 has enough, too much or too little blast. Too much de- pendence should not be placed upon air-gauges, as they may show a great pressure of blast, and the tuyeres be too small to admit of volume enough of blast to do good melting. The air-gauge will invariably show more pressure of blast toward the last of the heat, when the tuyeres have become bunged up, than at the first of the heat, yet the cupola will have less blast. Too little blast will cause slow melting; too much blast will harden the iron and make it dull, unless too much fuel is used. See Combustion and Heat. DUMPING THE CUPOLA. The blast should be taken off as soon as there is enough iron melted. It is better for the cupola to drop the bottom with a little unmelted iron in it than it is to melt every drop before dropping the bottom. Ten min- utes blowing after the iron is all melted, will make the cupola harder to dump, and will injure the lining more than two hours melting would do when the cupola was full of stock. The melter should never throw iron into the cupola after the stock gets too low, or the iron is all melted. If a little more iron is charged in a small cupola than is wanted, it will make it easy to dump ; the bottom should never be dropped when there is any molten iron in the cupola. FIRE IN THE DUMP. Some melters never put out the fire in the dump, but allow it to burn out. This should not be done, for there is a great deal of fuel dropped through the cupola, partly burnt, that may be used again in the cupola or 68 FOUNDING OF IRON, under the boiler ; and by allowing it to burn up in the dump it does no good, but does harm in cementing the dump more solidly together and making it harder to shovel out. THE DUMP. The dump should be carefully picked over as it is taken out from under the cupola, and the large pieces of iron and fuel thrown out. If the old sand bottom is to be put in again, it should be riddled out of the dump and the cinder should be put in the mill and ground, and all the iron carefully picked out of it. If there is no mill, the cinder should all be broken up fine and riddled through a No. 2 riddle, so as to get all the iron. Some melters throw more iron away in the dump, every day, than would pay their wages. I have seen old men and women make a good living, at Pittsburg and other places, by gathering the iron out of the dumps from cupolas after they had been thrown out on the bank of the river, and selling it for one-fourth cent per pound. PIG MOLD FOR OVER-IRON. Stove molders alw^ays have more or less little dribs of iron left in their ladles, which they cannot pour into their work ; and these little dribs will generally make the iron too dull to run their work if they are kept in the ladle until the next catch ; so, to get rid of it, the molder will pour it down in the gangway, or at the back end of his floor, or most any place. In this way a great deal of iron is lost in course of time ; or if it is not lost, it becomes mixed with sand and dirt, and will make a dirty iron when re-melted. To prevent this waste of iron, the foundryman should have a cast-iron FOUNDING OF IRON. 69 pig mold (as shown in fig. 17) set in the gangways at the head of each man's floor, so that the molder can pour all the little dribs of over-iron into it, and collect them in one pig. These molds are the best when made to hold about half a ladle of iron ; they can then be easily turned over, and the iron turned out, and the mold re-filled, if necessary ; or the molds may be made larger, and a few of them set around the cupola instead of in the gangways. These pig molds have been made Fig. 17. with a swivel on each end, and hung in a cast-iron frame, and are dumped by means of a crank, when full, and again re-filled ; but this arrangement has generally been abandoned in favor of small molds in the gangways, and a few large ones around the cupola. Care should always be taken to have these molds dry and clean, and the molder should always be careful to pour the iron into them slow at first, and heat the mold gradually to prevent the iron from exploding. COMBUSTION AND HEAT. All ordinary processes of fermentation, decay and fire are produced by a union of oxygen with a sub- stance, and are only different forms of combustion ; they diff'er in the time employed in the operation. If oxygen unites rapidly, we call it fire ; if slowly, decay. Yet the process and the products are the same in the combination of an atom of oxygen with an atom of car- bon, — a certain amount of heat is produced. Hence, the house that decays in fifty years gives out as much 70 FOUNDING OF IRON. heat during that time as if it had been swept off by a fierce conflagration in as many minutes. If we supply our cupolas with oxygen rapidly, the combustion will be rapid and the heat intense. If we supply it slowly, the combustion will be slow and the heat mild. Hence, the use of a blast for our cupolas. In order to form a thorough combustion of fuel, every two atoms of oxygen must unite with one atom of carbon. If less than two atoms of oxygen are supplied to one atom of carbon, the combustion is not thorough. If more than two atoms of oxygen are supplied to one of carbon, it will not form a chemical combustion, but a mechanical destruction of the fuel. If the blast is too mild, we have a thorough combustion, but we do not have a rapid combustion, nor an intense heat; and more fuel and more time is required to make hot iron, but there will be little or no slag ; there will be more ash, and the cinders in the cupola will be brittle and easy to pick out in a short heat ; but if the cupola is kept in blast for a long time, the ash may become cemented together and form a tough cinder, and the cupola will be hard to pick out. If we have too much blast, or a too sharp and cutting blast, the oxygen cannot combine with the carbon of the fuel so rapidly, but it will overcome the carbon, and will make an intense heat ; but the heat will be short-lived. The iron cannot take up the heat so rapidly, and more fuel is required to make hot iron ; and there is not a chemical combustion of the fuel, but a mechanical destruction ; for the oxygen of the blast combines with the carbon of the fuel so rapidly that the non-carbonic residue of the fuel is not consumed, but is converted into a slag. Foundrymen will often notice that they have more slag on one day than another. This slag is generally caused by more blast on one day than another ; and more blast may be supplied by running the fan or blower faster, or by charging the cupola so that it is FOUNDING OF IRON. 71 choked down, and the carbonic-acid gas cannot escape. Hence the cupola should be charged even, and the fan or blower run to suit the cupola. If we only supply the cupola with enough oxygen to form a thorough and rapid combustion, the heat will be intense, and will make little or no slag; for the non-carbonic residue of the fuel will be converted into an oxide or light cinder, and will be carried out at the top of the stack, — less fuel will be required to make hot iron, and it will be melted at a more even temperature, and make a better casting. I have often seen two ciipolas made up in the same shape, and both melting the same irons ; one of them would make a great deal of slag, and be hard to pick out, while the other made little or none, and was easy to pick out. This was because the cupola that made the slag had too much blast. • Chemists tell us that, in order to produce a perfect com- bustion, we must have two atoms of oxygen to one atom of carbon; but the question is, how are we to know when we have two atoms of oxygen or one atom of carbon, or how are we to know when we have too much or too little blast? This is a question that can only be answered by practical experience, as no rule can be given that will hold good in all cupolas. Yet I might make some suggestions that would assist the foundry- man in regulating his blast. In visiting different foun- dries through the country, I have found that scarcely any two cupolas are charged exactly alike, although they may be exactly the same size, and, to all appear- ance, the same. Yet the stacks may not be so high, or one cupola may be set along side of a high building or down in a hollow, so that it will have little or no draft; and if charged exactly the same as a cupola that has a good draft, the result would be that we would not have a thorough combustion, and probably we would have a •dull iron. Still this cupola with the poor draft may be charged so as to do good melting; but it cannot be 72 FOUNDING OF IRON. made to do as fast melting as a cupola with a good draft. Thus we may, by varying our charges of fuel and iron, produce a thorough combustion, and do good melting in any cupola. I should recommend fast melt- ing in cupolas, a good strong volume of blast, and a varying of the charges of fuel and iron to suit the blast and cupola. I should recommend high stacks on cupo- las, and a good draft. I should recommend charging the iron compactly together, so as to utilize all the heat from \hQ fuel ; but the iron should not be packed so- close as to form a complete damper over the fuel, and nof admit of the escape of the carbonic-acid gas whick is formed by the combustion of the fuel. THE MELTING- POINT. The theory that iron in a cupola is melted all up through the stock is wrong, for every cupola has a cer- tain point at which the iron is melted, and there is not a pound of iron melted in any cupola until it comes- down to the melting point. The melting point in a cupola is generally from six to eighteen inches above the tuyeres, but it may be raised or lowered a little by increasing or diminishing the amount of fuel in the bed ; but if we get the bed too high it throws the melt- ing point too high, and the result will be slow melting. If we get the bed too low, it will allow the iron to get below the melting point, and the result will be dull iron ; and in order to do good melting in any cupola, it is very essential that the melter should know the melt- ing point of his particular cupola. The melting point of a cupola is the point at which the most intense heat is created by the action of the blast upon the fuel. This intense heat at the melting point will cut the lining more than at any other place in the cupola, and th& FOUNDING OF IRON. 73 lining will generally be found to be cut out more just above the tuyeres than at any other point, which indi- cates the melting point of the cupola. If the tuyeres are put in so as to distribute the blast evenly through the stock, and the charges of iron and fuel are put in evenly, and every charge leveled up properly, the heat will be even all through the cupola, and the lining will be cut out in a regular belt at the melting point all around the cupola. On the other hand, if the tuyeres are not put in so as to distribute the blast evenly through the stock, or the charges of iron and fuel are not put in even and level, or if the fire is all on one side of the cupola, the heat will not be even through the cupola, and the lining will not be cut out in a regular belt at the melt- ing point, but will be cut full of holes, which shows that the cupola is not melting all around, but is only melt- ing in spots. By this irregular charging and melting in spots, the cupola may be reduced to half its melting capacity, which accounts for a cupola melting fast on one day and slow on another day. As before intimated, the melting point in a cupola is the point at which the most intense heat is created by the action of the blast upon the fuel. When the blast enters the cupola it is cold, and as it passes through the heated fuel it becomes hot, and as it becomes hot it creates heat by combina- tion with the fuel, and makes an intense heat. If we have a very strong blast it will travel fast and will pass through the fuel rapidly, and it will have to pass through more fuel before it becomes heated sufficiently to make an intense heat by combination with the fuel. On the other hand, if we have a mild blast, the blast vdll pass through the heated fuel slowly, and is more heated, so that it does not have to pass through so much fuel before it becomes sufficiently heated to make an intense heat by combination with the fuel; so that when we have a strong blast the melting point of a cupola is higher than when we have a mild or weak 74 FOUNDING OF IRON, blast ; and the bed has to be put in higher in a cupola with a high melting point than in a cupola with a low melting point, which accounts for one cupola requiring more fuel in the bed than another cupola does. When the cupola is in blast, the bed or fuel in the bottom of the cupola is constantly burning up, and the unmelted • iron will get down below the melting point. To pre- vent this, the melter has recourse to charges of fuel between the charges of iron, and as the charges of iron are melted and drawn out at the tap hole, the charges of fuel come down and replenis-h the bed and again raise the melting point ; the next charge of iron comes down and is melted and drawn out ; the bed is reduced and is again replenished by the next charge of fuel, and so on through the whole heat. If we supply too much or too little fuel between the charges of iron, the melting point will be raised too high or reduced too low, or in other words, if we have a melting point of ten or twelve inches in height in our cupola, and we supply twenty or twenty-five inches of fuel, this extra fuel must all be burnt up before the iron can come down to the melting point ; and we will not have a continuous melting, but will have a delay between each charge of iron. If, on the other hand, we have only five or six inches of fuel between the charges of iron, when we should have ten or twelve inches, this small amount will not more than half replenish the bed, and the unmelted iron will get down too low and will not make hot iron, and the iron may not be melted at all ; and in order to do either fast or economical melting, we must not use either too much or too little fuel, and we must have the fuel distributed so as to suit the particular cupola in which it is used; for, as before explained, there are scarcely two cupolas that will melt exactly alike on account of the melting point being higher or lower, which is caused by a stronger or weaker blast, or by more or less draft ; and in order to do good melting, FOUNDING OF IRON. 75 the melter should not charge his cupola just the same as some other cupola of the same size is charged be- cause that cupola does good melting charged in that way ; but he should vary the height of the bed and the amount of fuel between the charges of iron, and the amount of iron on the bed and on each charge of fuel, until he finds the exact proportions that will do the best melting in that particular cupola. Melters, in changing from one cupola to another, will generally have trouble in making hot iron, and they will often make a complete failure of melting in a strange cupola. This is simply because they undertake to charge that cupola the same as some other cupola that they have been melting in, and they never pay any attention to the draft, blast, or the melting point of the cupola, which is the cause of their failure in melt- ing in a strange cupola. When a melter takes charge of a strange cupola, his first object should be to study the draft of the cupola, the nature of the blast, and to ascertain the melting point of the cupola. He can gen- erally tell where the melting point is by noticing where the lining is cut out the most, and he can tell whether the cupola is melting evenly, or is only melting in spots, by noticing whether the lining is cut out in a regular belt all around the cupola, or is only cut out in holes, as before explained. He can tell whether the bed is too high or too low by noticing how the cupola melts. He can tell whether he is using too much fuel between the charges of iron, or if he is putting in the charges of iron too heavy, by noticing whether the cupola melts regularly or not, and by noticing if it makes regular iron ; for if the iron is very hot in one part of the heat and dull in another part, it is a sure indication that the fuel is not properly distributed through the iron, and it should be remedied by increasing or diminishing the weight of the charges of fuel or iron. In melting with coke, the melter cannot put in his 76 FOUNDING OF IRON. iron in as large charges as he can with coal, because the coke is more bulky than coal, and he has more bulk in the same weight, and if he puts the same weight of coke between the charges of iron as he does of coal, the bulk of the coke will raise the iron above the melting point, and the iron cannot be melted until part of the coke is burnt up so as to allow the iron to come down to the melting point, and the result is that he does not have a continuous melting, but he has a delay between each charge of iron, and the iron will probably be dull in the latter part of each charge ; but the melter can do equally as regular melting, and can do faster melting with coke than he can with coal, by putting in the coke and iron in smaller charges, and more of them, which proves conclusively that good melting can be done with almost any fuel and in any cupola, if the melter under- stands his business; but he may not be able to do as economical melting in a poor cupola as he can in a good one. BLAST MACHINES. All the old style blast machines, such as the leather bellows, the trompe or water blast, the chain blast, and the cogniardelle or water-cylinder blast, have gone out of use in the foundries in this country, and have gener- ally been replaced by the cylinder or piston blowers, and these last are rapidly giving way to the more mod- ern machines, which are cheaper and require less power to run them. The principal improved blast machines that are in use in foundries at the present time are, the McKenzie blower, the Root blower, the Baker blower, the Clark fan, and the Sturtevant fan. The McKenzie blower is a pressure blower ; it is manufactured in the State of New Jersey, and is the oldest rotary pressure blower in use. It is in general use all over the country, ' FOUNDING OF IRON, 77 and gives a good blast. The Root blower is also a pres- sure blower ; it is manufactured in the State of Indiana, and is in general use through the West. The Baker blower is also a pressure blower ; it is manufactured in Philadelphia, and is in use in a great many foundries in Philadelphia and New York. The Sturtevant fan is not a pressure blower ; it is manufactured in Boston, and is in general use all over this country. The Clark fan, like the Sturtevant fan, is not a pressure blower ; it is manufactured in the State of New Jersey, and is in general use all over this country. All the above blowers and fans are rotary blowers or fans. I have melted iron with all these blowers and fans, and have been able to do as fast and as economical melting with the one as the other. Any of them will make a good blast for a cupola, and the only advantage that any of them have over the other is in the power required to run them. The blowers are all sold at about the same price, but there is considerable difference in the price of the fans ; the Clark fan is sold a great deal the cheapest. There should be some little difference in charging a cupola where a fan or blower is used, for the fan blast is not a forced blast, and the stock can be charged in a cupola so compactly together as to choke it down and shut off the blast ; and in charging a cupola the iron should not be packed in too solidly, nor should it be packed too open, or the heat will escape up the stack and more fuel will be required to make hot iron, but we must keep between the two extremes. Even if a forced blast is used, the stock should not be packed too solidly, for the carbonic acid gas formed by the combustion of the fuel cannot escape and will injure the iron. The Disston Centennial Pressure Blower is a new blower that has lately been invented, and is manufac- tured in Philadelphia. I have not seen any of these blowers in use in foundries, but they are said to be a first class blower. 78 FOUNDING OF IRON. THE ATMOSPHERE. It is often claimed by foundrymen and melters that the changes in the atmosphere affect the working of the cupola and the melting of iron, and that less fuel is required to melt iron on a damp or cold day than is required to melt the same iron on a warm, clear day. I have watched these points closely, and have observed that iron melted on a cold or dark day seems hotter than iron melted on a warm, clear day. This is be- cause there is more contrast between the molten iron and its surroundings. If we light a candle in daylight the flame will seem to make less light than it would at night or in the dark, yet there is the same amount of flame and the same amount of gases consumed. A bar of iron that would look black-hot in daylight, would look red-hot in the dark, yet it will not burn you any worse in the dark than it would in the light. If we heat a bar of iron in the forge and draw it out of the fire suddenly, it will look hotter than w^hen it lay in the fire, because we see more contrast between the hot iron and the cold air than we did between the hot iron and the hot coals ; yet there is often a real difference be- tween the working of the cupola on one day than on another. Some melters make a practice of lighting their fire in the cupola at a certain time, and charging the iron at a certain time every day. On a bright, clear day the the cupola will draw better than it will on a damp, rainy day, and the bed will be burnt more on a clear day, and will probably make a duller iron than it would on a damp, rainy day. When the cupola had little or no draft, and the bed was not so much burnt up, the melter will generally attribute the difference in the iron, on a rainy day and a clear day, to the effect of the atmos- phere on the cupola and iron, when really the difference FOUNDING OF IRON. 79 is caused by the way in which the bed is burnt. This may all be overcome by watching the wind and weather, and lighting the fire a little sooner or later, to suit the draft of the cupola. From what I have observed, I do not think that the changes in the atmosphere make any difference in the melting of iron in a cupola, except as explained above. FLUXES AND FLUXING-. These terms are respectively applied to substances which impart igneous fluidity when heated with other substances, and to the manner of using them. The alchemists tried to discover a fluid which should have the property of dissolving all things wherewith it might come in contact. They neglected to reflect that a neces- sity would arise for a vessel to keep it in. Practice demonstrated the fact, that coal or coke-smelted iron was inferior to charcoal-smelted iron. Analysis of coal or coke-smelted iron demonstrates the existence of both sulphur and phosphorus, and that the amount of dete- rioration in the iron was in direct proportion to the quantity of these elements which the fuel contained. With a view of getting rid of these impurities, and making a coal or coke-smelted iron equal to a charcoal- smelted iron, the manufacturer has had recourse to fluxes and fluxing in the blast furnace, and for the pur- pose of imparting igneous fluidity, the blast furnacemen have ,used lime, or the carbonate of lime, as a flux, and they have assisted in improving the quality of the iron and in carrying off the non-metallic residue of the ores in the shape of cinder or slag ; and foundry men, thinking that what is good as a flux in a blast furnace must be good as a flux in a cupola, have adopted the use of lime or the carbonate of lime as a flux in their foundry cupo- las, but they have neglected to reflect that there is a 80 FOUNDING OF IRON. great difference between a blast furnace and its work- ings, and a cupola and its workings. The blast fur- nace is stocked with ores that have a non-metallic resi- due which must be carried off'; the foundry cupola is stocked with pig-iron, which has little or no non- metallic residue ; the blast furnace is kept continually in blast, and the stock is subjected to from twenty-four to forty-eight hours heat in the furnace before it is tapped out in the shape of iron and cinder ; the foun dry cupola is only in blast for a few hours, and the stock is only subjected to the heat of the cupola for a a short time ; and whereas lime or the carbonate of lime does improve iron in a blast furnace where it is sub- jected to a long, continuous heat, they will not affect the iron in a foundry cupola where the iron is only sub- jected to their influence for a few minutes. And in order to flux and improve iron in a cupola, the foundry- man must have recourse to a more powerful flux than lime or the carbonate of lime. With a view of discover- ing a flux that would affect iron in a foundry cupola, I have spent a great deal of time and money in experi- menting on fluxes and fluxing, and I now have the best chemical flux ever offered to the public for use in foun- dry cupolas. With the aid of my flux almost any iron can be run into first-class work. LIME ST O.N E FLUX. Limestone has been used as a flux in the melting of iron, for centuries, and is used more or less at the pres- ent time. Most of foundrymen who use limestone con- sider a small riddle-full, finely broken up, sufficient for a heat of three or four tons of iron, but in some parts of the country, and in Cincinnati, Ohio, some of the foun- drymen charge large quantities of limestone into their FOUNDING OF IRON. 81 cupolas, and tap slag the same as a blast furnace. This they claim purifies the iron. I have seen limestone used at the rate of one hundred and fifty pounds to the ton of iron (at Zanesville, Ohio) in a straight cupola forty inches in diameter, and slag tapped. I do not consider that the use of limestone in a cupola, either in large or small quantities, is any advantage either in melting or cleaning the iron ; in fact I have fouij-d it a great disadvantage by careful tests made with and without it. Careful tests were made at the foundry of James Marshall & Co., Pittsburg, Pa., in 1874 : 35,150 pounds of iron were charged in the Truesdale Xjatent cupola ; 32,144 pounds obtained; 3,006 pounds lost in melting, with a large percentage of limestone and slag tapped. 33,000 pounds of iron were charged in their common straight cupola ; 31,235 pounds obtained ; 1,765 pounds lost in melting, without any limestone or other flux. The loss with the limestone was 3,006 pounds, while the loss without it was 1,765 fjounds, showing a difier- ence in favor of no limestone of 1,241 pounds, or a little over three per cent. When limestone is used in a cupola in small quanti- ties, it makes a heavy, tough slag that will run out at the tapping hole and bung up the spout and ladles. I claim that limestone should never be used in a cupola, either in large or small quantities, for the following reasons : 1st. It takes coal or coke to melt it. 2d. It don't do the , iron or the cupola any good after it is melted. 3d. It makes the slag in the cupola tougher and harder to pick out, especially if the limestone is poor. 4th. It makes the wastage of iron greater. 6 82 FOUNDING OF IRON, OYSTER-SHELL FLUX. Oyster shells are, like limestone, extensively used as a flux in melting iron in cupolas, but they are worse than limestone. It is a well-known fact that shells con- tain a large percentage of phosphorus, and in using them as a flux in the cupola, the phosphorus is taken up by the iron and is by it made a cold-short, harder and weaker iron. The use of shells in large quantities makes it necessary to use a much higher grade of iron to produce an equally good casting. FLORA-SPAR FLTJX. Flora-spar has been used as a flux in melting iron in cupolas, and it makes a very good flux if the flora-spar is pure ; but when it is poor it is very hard on the lining of the cupola, and for that reason it has gener- ally been abandoned as a flux in cupolas. MARBLE-SPALLS FLUX. Marble-Spalls are sometimes used as a flux in cupolas ; they make a very good flux, and I should recommend using them in small quantities. PATENT FLUXES. Several patent fluxes have been invented, and intro- duced and used with more or less success. My Patent Flux Is The Best. FOUNDING OF IRON. 83 CHARCOAL FLUX. Sometimes charcoal is used as a flux. It is put into the cupola in small quantities with the iron and fuel, and is very good to give life to the iron ; but it is dan- gerous on account of fire, as it is easily blown out of the cupola, and the sparks may set fire to the foundry or other buildings. POTATO FLUX. A raw potato is sometimes stuck on the end Of a tap- ping bar and put down to the bottom of a large ladle of iron ; this makes the iron boil and throws the dirt to the top of the iron, when it can be skimmed off. CLEAN IRON AND SOUND CASTING-S. The best way to clean iron and make good, clean and sound castings, is to melt the iron good and hot, and pour it hot and fast. The quicker iron can be put into a mold the better. If the sand will not stand hot iron it is not good molding sand, and should not be used for molding. The most of the dirt and dross in castings is caused by the molder allowing his iron to stand in the ladle until it is nearly set, so as to allow, the dirt to rise to the top of the iron and be skimmed off before the iron is poured; they will then dribble it into the mold and the casting will be full of dirt and dross, when, if the iron was poured hot and fast, it would have life enough to carry any dirt that might be in the mold up and out of the riser, and the dross in the iron would have a chance to rise before the iron sets. 84 FOUNDING OF IRON. POLLING- IRON. Some foundrymen, in order to mix the different brands of iron proper!}'- in the reverberatory furnace, poll the iron. This is done by taking a long pole of hickory, or some other strong wood, and running the end of the pole into the molten iron and stirring the iron with it. The wood poll is better for mixing the iron with than an iron bar is, for the wood causes the iron to boil around it ; and we not only stir up the iron, but we boil it up and cause it to mix more thoroughly than if we only stirred it up with an iron bar. Iron is sometimes polled in a large ladle after it has been melted in a cupola, and it is said to improve the quality of the castings. Iron may be thoroughly mixed in a ladle by putting a raw potato on to the end of a tapping bar and stirring the molten iron with it. A ball of clay, or anything that will cause the iron to boil gently, is equally as good as a potato. I should recommend polling iron in all cases where the iron is tapped in large ladles, and it is desirable to make a first-class casting. SLAG. Some melters are always troubled with slag running out at the tapping hole with the iron and bunging up the spout of the cupola. This slag may be caused by limestone or oyster shells used as a flux, or by the sand on the pig-iron, or rust on the -scrap, or by fine coal and sand shoveled into the cupola with the fuel or iron, or by slate in the coal or coke. The careless way in which some melters put in their sand bottom and the front or breast, will cause slag to run out at the tapping hole ; but one of the principal causes of slag is the careless FOUNDING OF IRON. 85 way in which sand or dirt is shoveled into the cupola. Some melters never sweep or clean up the floor of the scaffold, but shovel all the dirt into the cupola with the fine iron or scrap. This dirt is all melted and converted into slag. Another cause of slag is the unthorough combustion of the fuel, or too much blast. This trouble may be overcome by reducing the blast or increasing the fuel. See Combustion and Heat. DAUBING FOR LADLES. Molding sand mixed with a little clay-wash or mo- lasses-water makes a good daubing for hand ladles or other small ladles; loam, horse-manure and a little sharp or fire sand make a good daubing for any sized ladle. Salt should never be used in daubing for ladles, for it will make them harder to dry, and will draw the dampness after they are dry if left standing for a while, and will cause the iron to boil in the ladle. Fire clay or any other heavy clay should never be used for daub- ing ladles (especially small ones), as it is almost impos- sible to get them dry in the oven so that the iron will not boil in them. The first catch ladles should be daubed as lightly and evenly as possible, so as to have them dry evenly and quickly, and be light to handle without any danger of their cutting through and run- ning out. Large ladles that have to be daubed heavily should be perforated with small holes around the bot- tom so as to allow the gas to escape when the daubing is not thoroughly dry without boiling the iron. If the daubing is painted with a little blacking mixed with water, the iron will not stick to it. 86 FOUNDING OF IRON. LADLE REST. Fig. 18. Fig. 18 represents a ladle rest for rest- ing the double end of the shank upon while the moulder is pouring the iron. This rest is made by taking a piece of wood two or two and a half inches square and three feet long, and driving spikes into it four or five inches apart, and allow- ing the spikes to project out three or more inches from the wood. The skimmer-boy carries this rest around with him and sets it down at any place where the molder may wish to pour, so that the molder may rest the shank upon the spikes. By this arrangement the ladle may be held up with ease, and held more steadilj^ than a man could hold it by hand. PERCENTAGE OF FUEL. There is a great difference of opinion in regard to the amount of fuel required to melt a ton of iron, and there is a great difference in the amount actually used, as will be seen by reference to test heats made in different foundries in different parts of the country. Some foun- drymen will claim that they are melting from ten to twelve pounds of iron to one pound of fuel, and they will get out their books and show you the exact amount of fuel used and iron melted, which will figure out very well ; but in most of these cases the old melter has neg- lected to weigh the few little pieces of coal or coke that he has put in to fill up the holes, and these little pieces FOUNDING OF IRON. 87 sometimes amount to considerable. Other foundrymen will claim to be melting as high as fifteen or eighteen pounds of iron to one of fuel, but if you question them closely, you will generally find that the bed has not been counted in, and they are only figuring on the fuel used between the charges of iron. I have found that the percentage of fuel actually re- quired to melt a ton of iron will vary according to the quality of the fuel used, the construction of the cupola, the pressure of the blast, the way in which the iron is charged, the way in which the bed is burnt, and the amount of iron melted. A larger percentage of fuel is required to run off a small heat than would be required for a large heat in the same cupola. The best melting I have ever done, or ever seen done in a cupola, is seven pounds of iron to one pound of coal, and eight pounds of iron to one pound of Connellsville coke, and four pounds of iron to one pound of gas-house coke made from Pittsburg coal. I have found the average melting in foundries that I have visited, to be about four pounds of iron to one of coal, and about five pounds of iron to one of Connellsville coke, and about three pounds of iron to one of gas-house coke. Too much fuel is as bad as too little, and the amount actually required can only be ascertained by test, as no rule can be given that would hold good in all cupolas. The following heats that have been melted in different cupolas show the percentage of fuel used and the mode of charging. Most all of these heats were made in large foundries, where the stock is all weighed and melting is done sys- tematically ; and they represent a better average melt- ing than is actually done through the country; but they show no better average melting than is actually done in the foundries where these heats were made : 88 FOUNDING OF IRON, Melting and mixing done at a large Stove Foundry in Albany, N. Y., July 29, 1876, in a straight cupola, ivith large coal all through the heat; fire lit at 12 m.; iron charged at 1 p. M. ; blast on at 3 p. m. ; bottom dropped at 5 p. m. ; cu- pola 60 inches in diameter ; five oval-shaped, tuyeres 7 i by 83 inches ; tuyeres 4 inches above the sand bottom ; on the backside; cylinder blast used. p" c Coal. 03 03 oTr-! II §-■ II < §-• 03 Lbs. ft «3 III sizi "3 Bed 1800 400 400 168 168 164 164 168 108 100 100 100 100 1100 1100 list charge, 400 168 164 168 100 100 1100 j 4400 lbs. 400 168 164 168 100 lOJ 1100 1st charge ... 350 400 168 164 168 100 100 1100 400 168 164 168 100 100 1100 2d charge, 400 16S 164 168 100 100 1100 [ 4400 lbs. 400 168 164 168 100 100 1100 2d charge . . . 350 400 168 164 1H8 100 100 1100 400 168 164 168 100 100 1100 1 3d charge. 400 168 164 168 100 100 1100 ^ 4400 lbs. 400 168 164 1(;8 100 100 1100 3d charge . . . 350 400 168 164 168 100 100 1100 1 400 168 164 168 100 100 1100 I 4th charge, 400 168 164 168 100 100 1100 ( 4400 lbs. 400 168 164 168 100 100 1100 J 4th charge . . 350 400 168 164 168 100 100 1100 400 168- 164 168 100 100 1100 ! .')th charge, '■ 4400 lbs. 400 168 164 168 100 100 1100 400 168 164 168 100 100 1100 ) Gr'nd total j 22000 lbs. ! 1 Total.... 3280 8000 3360 3280 3360 2000 2000 22000 In this heat the chunks and scraps were counted as sprews. FOUNDING OF IRON, 89 Melting and mixing done at one of the leading Stove Foundries of Albany^ N. Y., September 2^, 1876, w a straight cupola about 70 inches in diameter ^ ivith cylinder blast ; large coal was used all through the heat; fire ivas lit at 11.30 A. m. ; iron charged at 12.15 p. m.; blast put ow a^ 2.30 p. m,; bottom dropped at 5 30 p. m. Coal. 2 CO 5 o "2 o .2 >-> ^ o CO -1^ Lb . 5^ X^ ^^ J3 Q o Eh Bed 1900 500 '200 500 500 400 500 400 500 400 .500 300 300 2500 2500 '~ 1st charge, ) .5000 lbs. 1st charge... 350 300 500 400 400 300 100 2000 \ 2d charge, ) 4000 lbs. 500 400 400 400 300 2000 2d charge ■too 300 500 400 400 300 100 2000 ) od charge, ) 4000 lbs. 300 500 400 400 400 2000 3d charge. . . . 400 300 500 400 400 400 . • . 2000 ) 4th charge, 4000 lbs. 300 500 400 400 400 2000 4th charge... 400 300 500 400 400 400 2000 ) 5th charge, ) 3600 lbs. 200 400 300 300 300 ioo 1600 5th charge... 400 300 500 400 400 400 2000 \ 6th charge, ) 3500 lbs. 200 400 300 300 300 1500 6th charge... 400 300 500 400 400 400 2000 1 7th charge, ) 3500 lbs. 200 400 300 300 300 1500 7th charge . . . 400 300 500 400 400 400 ... 2000 ) 8th charge, ) 3500 lbs. 200 400 300 300 300 1500 , Gr'nd total 31100 lbs. Total 4650 4200 7600 6100 6100 5900 1200 .31100 My flux was used in this heat. Melting done at one of the largest Stove Foundries, in Albany, N y., in 1876, in straight cupola, six feet in diameter in the shell, and lined loith six inch brick ; cupola five feet in the clear, six oval shaped tuyeres, four by twelve inches ; Stur- tevant fan blast : Lbs. Lbs. Coal in the bed . 2,200 Iron on the bed 7,200 First charge of coal . . . . 400 Split of coal . 100 Second charge of iron . 7,200 Second charge of coal. . . 400 Split of coal . 250 Third charge of iron . . 7,200 Third charge of coal . . . 400 Split of coal '. . 250 Fourth charge of iron . 7,200 Fourth charge of coal. . 400 Split of coal . 350 Fifth charge of iron , . . Total iron melted . . 7,200 Total coal used 4,750 36,000 In this heat the iron was put into the cupola in charges of 7,200 pounds, and in the middle of each 90 FOUNDING OF IRON, charge of iron a small charge of coal was put in; this is designated a split, when really it is only putting in the iron in charges of 3,600 pounds with one large charge of coal, and the next one small. Melting done at the Car Works, at Berwick, Pennsylvania, March 25, 1876 : Lbs. Coal in the bed 1,900 Coal in tirst charj^e 500 Coal in second charg-e . 600 Coal in third charge. . . 700 Total coal used 3,700 Lbs. Iron on the bed . 4,350 Iron in tirst charg-e 4,350 Iron in second charg:e . 4,350 Iron in third charge. . . 4,350 Total iron melted. . . . 17,400 The cupola was an oval-shaped cupola, called a fifteen ton cupola, with round tuyeres three and a half inches in diameter; the coal used was soft anthracite, from the Wilkesbarre region, and in order to keep up the bed, the charges of coal had to be increased towaixi the last of the heat ; the iron melted was a mixture of cold blast iron and steel rails, for car wheels. Melting and mixing, done at one of the leading Stove Foundries of Albany, NY., on September 28, 187G, in a straight cupola, about 50 inches in diameter, with cylinder blast ; large coal tvas iised in the bed, small coal between the charges ; fire lit at 12 M. ; iron charged at 1 p. m. ; blast put on at 2.45 p. m., and heat melted in about two and a half hours : Coal— Lbs. in U a, 5 . boo >-> Hudson, No. 2. M O Lbs. Bed 1,500 1st charge, 350 2d charge, 350 3d charge, 350 4th charge 250 300 300 300 300 300 300 200 200 200 100 500 .500 500 500 500 500 500 500 400 200 .500 500 600 (JOO 600 600 600 700 600 500 500 600 600 600 600 700 600 600 200 200 2,000 2.000 2,000 2,000 2,000 2,000 2,000 2,000 1.800 300 } 1st charge, 4,000 }2d charge, 4,000 } 3d charge, 4,000 } 4th charge, 4,000 1 5th charge, 2,100 Total . . . 2,800 2,500 4, GOO 5,300 5,300 400 18,100 [-Gr'd total, 18,000 My flux was used in this heat. FOUNDING OF IRON. 91 Melting done at one of the Troy, N. Y., Stove Foundries, in 1876, in a straight cupola, six feet four inches in diameter in the shell, and lined with seven inch brick ; cupola five feet two inches in the clear ; six oval shaped tuyeres, three and a half by twelve inches, Sturtevant fan blast: Lbs. Coal in the bed 2,500 First charge of coal . . . 550 Second charg^e of coal . 550 Third charge of coal. . . 200 Total coal used 3,700 Lbs. Iron on the bed 8,000 Second charge of iron . 6,000 Third charge of iron . . . 6,000 Fourth charge of iron . 2,500 Total iron melted 22,000 In this heat the iron was charged in twenty hundred pounds drafts, thirteen hundred pig-iron, and seven hundred sprews and scrap ; fire was lit at 12 m., com- menced charging at 12.30 p. m., blast on at 2.30 p. m., bottom dropped at about 4.30 p. m., pressure of blast thirteen ounces. Melting and mixing, done at one of the Peekskill, N. Y., Stove Works, July 8, 1876, in a No. 4 McKcnzie cupola, ivith a Sturtevant fan ; large coal used all through the heat ; fire lit at 11.40 A. M., iron charged at 12.30 p. m., blast on at 2.30 p. M., tuyeres six inches above sand bottom : Coal— Lbs. 6 Is I— 1 m . eS o o Crane, No 1. Peekskill, No. 2. Sprews. Chunks. m c3 U Lbs. Bed 1,200 1st charge, 300 2d charge, 300 300 300 300 400 200 200 •:oo 200 300 300 500 400 600 200 500 ' 300 54© 200 500 200 1 500 400 600 300 400 300 400 100 2,000 200 2,000 1,500 100 1,.500 1,500 100 1,500 J 1st charge, 4,000 1 2d charge, 3,000 } 3d charge, 3,000 Total . . . 1,800 900 1,500 1,6003,100 2,400 500 10,000 \ Grand tot. 10,000 My flux was used in this heat. 92 FOUNDING OF IRON. Melting and mixing, done at a Stove Foundry, Green Island, N. Y., October 21, 1876, in a round cupola, 48 inches in diameter at the charging door, and about 35 inches in diameter at the ticyers ; four tuyeres, 18 by 2 inches, ivere used ; large coal ivas used for the bed, small coal between charges ; fire lit at 12 M., iron charged at 12.45 p. m., blast on at 2.30 p. m., bottom dropped at 4.30 p. m.; tuyers four inches from sand bottom on back side : Coal used. O Q 6 < ft 3 o H Lbs. In the bed.. 1st charge.. 2d charge . . 3d charge .. Total coal, 1,200 500 400 400 300 100 100 100 500 600 600 000 500 6oO 600 600 400 600 500 600 600 (iOO 500 6U0 300 300 300 300 300 300 300 300 1,500 1,500 1,500 1,500 1,500 1,500 1,500 1,500 1 1st charge, 3,000 1 2d charge, 3,000 1 3d charge, 3,000 1 4th charge, 3,000 1 Total iron, 12,000 2,500 600 4,600 4,400 2,400 12,000 My flux was used in this heat. Melting done at a Foundry in Poughkeepsie, N. Y., July 18, 1876, in a No. 4 McKenzie cupola ; coal used ivas small- sized hard coal, what is knoivn as grate or steamboat coal. The fire tvas lit at 12.30 p. m. ; iron charged at 12.50 p. m. ; blast on at 2.30 p. m., and iron ivas down in 25 or 30 min- utes ; Sturtevant fan blast ivas used. Coal used in the bed. . . First charge of coal . . . Second charge of coal.. Third charge of coal . . Lbs. 900 300 300 150 Total coal used 1,650 First charge of iron . . . Second charge of iron. Third charge of iron . . Fourth charge of ii'on , Lbs. 4,200 3,000 3,000 1,200 Total iron melted 11,400 This heat was melted in the same sized McKenzie cupola as the one used at the stove works at Peekskill, N. Y., and in this heat, as will be seen, there was almost one pound more of iron melted to the pound of FOUNDING OF IRON. 93 coal than was melted at Peekskill, and this iron was hotter and more even. This saving of coal and more even iron was caused by the small coal being used in place of large coal. When at Poughkeepsie, I sug- gested to the foreman of the foundry that he might ob- tain better results by lighting his fire sooner, and allow- ing it to get burnt up more before the iron was charged. He followed my suggestion and lit the fire an hour ear- lier, and charged the iron earlier and put on the blast at the same time. The result was, that the iron was down in five or ten minutes after the blast was put on, and one hundred pounds less coal were required for the bed. 3Ielting done at a Stove WorTcs in Baltimore, Md., in a straight cupola 60 inches in diameter. The fuel used was Lehigh Valley coal and Connellsville coke. « Lbs. libs. Coal in the bed 1,800 Iron on the bed . 5,000 First cliarg-e of coke. . . 2i:0 First charge of iron . . . 2,000 Second charge of coke. 200 Second charge of iron . 2,000 Third charge of coke . . 200 Third charge of iron . . . 2,000 Fourth charge of coke . 200 Fourth charge of iron. 2,000 Fifth charge of coke . , . 175 Fifth charge of iron 2,000 , Sixth charge of coke. . . 175 Sixth charge of iron . . . 1,500 1 Seventh charge of coke, 175 Seventh charge of iron 1,500 Eighth cliarge of coke . 175 Eighth charge of iron. 1,500 Nintli cliarge of coke . . 150 Ninth charge of iron . . 1,500 Tenth charge of coke . . 150 Tenth charge of iron. . 1,500 Eleventh charge of coke 150 Eleventh charge of iron , 1,500 Twelfth charge of coke, Total coal and coke used 100 Twelfth charge of iron. Total iron nielted .1,500 3,850 25,500 This way of making the bed of coal and the charges of coke has been adopted in some parts of the country, and seems to work very well. 94 FOUNDING OF IRON. Melting done in Cincinnati, Ohio, in a straight cupola, forty indies in diameter, with four round tuyeres three inches above the sand bottom, ivith Coymellsville coke and a Hoot hloiver. Coke used. d .s 'o m p O m First charge Second " Third *' Fourth " Fifth ♦' Sixth " Seventh *• 400 50 50 50 50 50 50 300 200 200 200 200 200 200 300 200 200 200 200 200 200 200 100 100 100 100 200 200 200 200 200 300 300 1000 700 700 700 700 700 700 Total iron melted , . . 700 1500 1500 600 j 1600 5200 Melting done at Louisville, Kg., in a straight cupola thirty inches in diameter with two round tuyeres six inches above the sand bottom, with old style fan and gas-house coke. The iron ivas used for house-work, and had to be hot. 1 Coke used. 6 O d .2 'o o o p Lbs. In the bed 500 First charge 100 Second charge 100 Third charge 100 Fourth charge 100 Fifth charge 100 200 100 100 200 100 200 200 200 100 100 200 100 300 100 200 100 200 200 100 100 100 100 800 1st cliarge iron. 500 2d charge iron. 500 3d charge iron. 500 4tli charge iron. 500 5th charge iron . 500 6tli charge iron. Total colve 1000 900 900 1100 400 3300 total ii-on. Melting done at one of the Cincinnati Stove Foundries, in the Truesdale patent cupola, tvith a Boot bloiver and Connells- ville coke : Ivbs. Coke in the bed 1,600 2 charges of coke, each 175 13 charges of coke, each 135 18 charges of coke, each 100 Total coke used 5,505 Lb^ Iron on the bed 4,000 2 charges of iron, each 1,500 13 charges of iron, each 1,000 18 charges of iron, each 1,000 Total iron melted 38,000 FOUNDING OF IRON, 95 Melting done at PittsburgJi in a No. 5 McKenzie cupola, with a Boot bloiver and Pittsburgli coke : Coke. 03 ft m 6 rH PI < a A O CO CO o Lbs. 1,000 200 200 150 400 300 400 300 200 300 300 200 400 400 300 300 300 200 300 200 400 400 300 300 200 300 200 300 200 300 200 200 1,400 2,600 1,200 1,800 700 1,300 800 1,200 1 4, 000 1st charge. 1 3,000 2cl charge. 1 2,000 3rfl charge. 1 2,000 4th charge. > Total iron melted. 600 600 500 200 400 100 400 100 1,550 2,400 2,400 2,400 GOO 1,900 1,000 11,000 Melting done at a Stove Foundry in St. Louis, Mo., in a straight cupola 50 inches in diameter, with Connellsville coke as fuel. Lbs. Coke in the bed 1,500 First charge of* coke 150 Second charge of coke. . 150 Third charge of coke... 150 Fourth charge of coke . . 100 Fifth charge of coke 100 Sixth charge of coke 100 Seventh charge of coke. 100 Eighth charge of coke . . 100 Ninth charge of coke . . . 100 Tenth charge of coke. . . 100 Eleventh charge of coke, 100 Twelfth charge of coke . 100 Thirteenth chai-ge coke. 100 Total coke used 2,950 Lbs. Iron on the bed 3,500 First charge of iron.... 2,000 Second charge of iron .. 1,500 Third charge of iron . . . 1,500 Fourth charge of iron .. 1,000 Fifth charge of iron 1,000 Sixth charge of iron 1,000 Seventh charge of iron. . 1,000 Eighth charge of iron. . . 1,000 Ninth charge of iron 1,000 Tenth charge of iron 1,000 Eleventh charge of iron. 1,000 Twelfth charge of iron . . 1,000 Thirteenth charge iron. . 1,000 Total iron melted 18,500 96 FOUNDING OF IRON, PERCENTAG-E OF FUEL AND CASTING'S. The following statements of melting was furnished to me by some of the leading stove manufacturers of Albany, N. Y., and represents the amount of iron melted, coal used, and castings produced in their foundries in the year 1876. The names of the com- panies furnishing these statements have been omitted by request : First Foundry. Tous. Lbs. Gross amount of iron melted 2,059 1,087 Amount of stock melted 1,300 1,860 Amount of clean casting-s net 1,344 919 The percentag-e of cleaned castings produced to the total iron melted 57.70 Percentage of coal used in melting 15.55 Second Foundry. Gross amount of iron melted 2,817 1,420 Amount of pig-iron melted * 1,842 1,871 Amount of cleaned castings net 1,960 889 Percentage of cleaned castings produced to the total amount of iron melted 62.12 Percentage of coal used in melting 14.51 Third Foundry. Gross amount of iron melted 1,818 930 Amount of pig-iron melted 1,123 42 Amount of cleaned castings net 1,128 1,407 Percentage of cleaned castings produced to total iron melted 65.42 Percentage of coal used in melting 15.17 Fourth Foundry. Gross amount of iron melted 1,009 415 Amount of pig-iron melted 661 702 Amount of cleaned castings net 664 707 Percentage of cleaned castings produced to total amount of irort melted 58.62 Percentage of coal used 17.22 FOUNDING OF IRON, 97 Fifth Foundi'y. Tons. Lbs. Gross amount of iron melted 3,328 84 Amount of pig-iron melted 2,118 521 Amount of cleaned castings net 2,216 987 Percentage of cleaned castings produced to total iron melted 56.35 Percentage of coal used in melting 16.12 The following statement was received from the largest Stove Foundry in the United States, as a statement of melting done last year : Tons. Lbs. Gross amount of iron melted 6,695 1,197 Amount of pig-iron melted 4,276 1,042 Amount of cleaned castings net 4,433 975 Net gain of castings over gross ton of pig-iron.. 166 1,442 Percentage of cleaned castings produced to total iron melted 58.41 Percentage of coal used in melting 15.08 The following statement show the percentage of fuel used and castings produced in the three different foundries in the year 1875 : Per cent. Per cent. Coal used 15.48 Coal used 14.70 Coal used 14.95 Cleaned castings 61.81 Cleaned castings 64.01 Cleaned castings 55.96 The following statement was received from a large stove foundry in Troy, N. Y., as statement of melting done in the year 1876 : Tons. Lbs. Gross amount of iron melted 2,009 987 Amount of stock melted 1,250 1,760 Amount of cleaned castings, net 1,294 819 Percentage of cleaned castings produced to total amount of iron melted 59.50 Perc^entage of coal used in melting 18.10 The following statements of percentage of castings produced and fuel used were furnished from diflferent stove foundries in different parts of the country : From Cincinnati, 1874. Cleaned castings 65.00 " " 63.26 " •' 59.72 Coke used 14.51 17.12 16.51 98 FOUNDING OH IRON. From Pittsburg, 1875. Cleaned castings 70.11 I Coke used 14.00 " ." 68.21 I " 15.75 From Baltimore, 1875. Cleaned casting's 69.13 I Coal and coke used ... . 15.01 ♦* " 66.71 I Coalnsed 20.00 From PhiladelpJiia, 1875. Cleaned castings 65. 19 " 60.49 " " 63.09 Coal used 18.72 *' 20.39 19.78 From Louisville, Ky., 1875. Cleaned castings 76.19 I Coke used 27.36 " 67.08 1 " 32.47 IRON LOST IN MELTING-. Very few foiindrymen have ever made any accu- rate tests to ascertain how much iron they actually lost in melting. The majority of foundrymen take it for granted that they lose from ten to twelve per cent. I have made a great many careful tests to ascer- tain the exact amount lost in melting, and I find that the loss will vary according to the quality of iron melted and fuel used, etc. A No. 1 iron will lose more than a No. 2 iron, because it is more open and the carbon is not so combined with the iron, but is more in the graph- ite state, and is more volatile and easily burnt away. Old stove plate, shot-iron and other light scrap will lose more than a No. 2 iron, because there is more surface exposed to the heat before it is melted, and there is always more or less rust and dirt on it. Burnt iron will lose more than good iron, because the life has all been burnt out of it, and we have only the bulk of iron without the body. The loss will be greater when the lOUNDING OF IRON, 99 fuel is poor than when it is good, because more bulk of fuel has to be used ; the iron is melted higher up in the cupola, and is longer in melting. The loss is greater in one cupola than in another, because the pressure of blast is greater or less ; the cupola is charged different and melts different. The loss is more when the iron is melted slow and dull than when it is melted fast and hot, because the prin- cipal loss takes place while the iron is being melted and is in the mushy state, and not after it has been melted and is in the molten state (a grate bar or an annealing box will all be burnt away and never melted). The loss will be greater in a machinery than in a stove-plate foundry, because their castings are heavier and there is not so much surface coated with sand as in stove-plate foundries, where the iron is cast in thin plates making a great deal of surface which has more or less sand on it, which is weighed and sold as iron. By careful tests that I have made in different foun- dries, I have found the average loss to be about as fol- lows : In stove-plate foundries, from two to eight per cent. ; in machinery foundries, with the average iron, from four to ten per cent. ; on old stove-plate and shot- iron, from twenty to thirty per cent. ; on burnt iron, from twenty-five to sixty per cent., according to how badly the iron was burnt. The following test heats were made at the Franklin Foundry and Pipe Works, James Marshall & Co., pro- prietors, Pittsburg, Pa. : Heat melted July 30, 1874, in the Truesdale patent cupola, tvith Kirk's chemical flux : Lbs. Amount of iron charg^ed was 88,150 Amount of iron obtained was 35,946 Amount lost in melting was 2,204 100 FOUNDING OF IRON. Heat melted July 31, 1874, in the Truesdale patent cupola^ tvith a large percentage of lime-stone and slag tapped : Lbs. Amount of iron charged was 35.150 Amount of iron obtained was 32,144 Amount lost in melting" was 3,006 Heat melted September 9, 1874, in their common straight cupola^ tvith Kirk's chemical flux : Lbs. Amount of iron charged was 33,000 Amount of iron obtained was , 32,561 Amount lost in melting was 439 Heat melted September 14, 1874, in their common straight cupola^ with lime-stone as a flux : Lbs. Amount of iron charged was 33,000 Amount of iron obtained was 31,235 Amount lost in melting was 1,765 The following test heats were made at the Vulcan Iron Works, Wilkesbarre, Pa. : Heat melted December 21, 1875, in their common straight cupola, with Kir¥s chemical flux : Lbs. Amount of iron charged was 13,500 Amount of iron obtained was 13,370 Amount lost in melting was 130 Heat melted December 24, 1875, in their common straight cupola, ivithout any lime-stone or other flux : Lbs. Amount of iron charged was 13,300 Amount of iron obtained was 12,799 Amount lost in melting was 501 The following test heats were made at the Wyoming Valley Manufacturing Co.'s Foundry, Wilkesbarre, Pa. : FOUNDING OF IRON. 101 Heat melted December 29, 1875, in their round bosh cupola, with Kir¥s chemical flux : Lbs. Amount of iron charged was 3,700 Amount of iron obtained was 3,645 Amount lost in melting' was 55 Heat melted December 30, 1875, in their round bosh cupola, with oyster shell flux : Lbs. Amount of iron charged was 6,200 Amount of iron obtained was 5,813 Amount lost in melting was 387 The following test was made at the Phoenix Foundry, Cincinnati, Ohio, January 25, 1875 : Lbs. Amount of pig-iron charged was 6,100 Amount of scrap charged was 1,400 Amount of fine rattle-barrel iron was 2,000 Total amount charged in cupola 9,500 Total amount obtained out of cupola 8,750 Total amount lost in melting 550 The following test was made at the Baldwin Loco- motive works, Philadelphia, Pa., June 26, 1874, in melt- ing shot-iron in a thirty inch straight cupola, with Kirk's chemical flux : ' Lbs. Amount of shot-iron charged 2,240 Amount of pig-iron obtained 1,797 Amount of iron lost in melting 443 The following test was made at the American Stove and Hollow-ware Ce.'s Foundry, Philadelphia, Pa., July 15, 1874, in melting a lot of badly burnt iron in a twenty-four ton McKenzie cupola, with the Lawrence tuyere in it, and Kirk's chemical flux : Lbs. Amount of annealing pots charged 2,200 Amount of pig-iron and scrap obtained 1,540 Amount of iron lost in melting 660 102 FOUNDING OF IRON. I do not consider this a fair test, as the cupola was entirely too large for t]^e amount of iron melted. Test heat made in the foundry of the Jackson & Woodin Manufacturing Company, to ascertain the wastage of iron. Tests were made under immediate supervision of their foundry formen : Heat melted March 24, 1876. Lbs. Lbs. Castings 5,029 Gates and scrap 469 Cinder scrap 287 Lump coal 2,002 No. 2 pig-iron 6,069 Limestone 160 Total iron put into the cupola 6,069 lbs. out of " 5,785 " Lost in melting 284 lbs. or say 4.7 per cent., or 105 lbs. per 2,240 lbs. Heat melted March 25, 1876. Lbs. Lbs. Lump coal 2,002 No. 2 pig-iron 6,069 Kirk's chemical flux used. Castings 4,380 Gates and scrap 1,036 Cinder scrap 504 Total iron put into the cupola 6,069 lbs. outof " 5,920 " Lost in melting 149 lbs. or say 2^ per cent., or 56 lbs. per 2,240 lbs. We hereby certify that the above experiments were carefully and impartially made at our works as above stated. The Jackson & Woodin Manufacturing Co., BY C. G. Jackson, Vice-President. MEL.TERS. In traveling through the country and visiting dif- ferent foundries, I have discovered that there are in existence, four different classes of melters. The first is FOUNDING OF IRON. 103 the Old Professional Melter who does not know any- thing about a modern cupola, and is too old to learn. He involves everything about the cupola in mystery, and makes out that it is an awful accomplishment to be able to run a cupola. Next comes the Smart-Alic Melter, who knows a little about a cupola, and has some good ideas and a great many bad ones ; he has no regularity about what he does, and has a great •deal of trouble with the cupola, but he always has a ^ood excuse for everything that goes wrong, so the boss thinks he is all right. Next comes the cheap melter, who does not know anything about a cupola, and does not make any pretence to know anything, but works along like a machine and gets his wages every Saturday night. He wastes a fearful lot of fuel and iron, and the molders lose heaps of castings on his account, but he works cheap and is kept on. Next comes the Practical and Scientific Melter, who does not make any great pretence to know anything, but who understands his business and attends to it; he does everything by rule and always has good hot iron. I have described these four melters at length, so that by comparison of them, the melters can see what is the cause of their trouble, and the foundrymen how they are imposed upon by melters. THE OLD MELTER. Scarcely one owner of a foundry in a hundred under- stands the melting* of iron, either practically or theo- retically, and there is not one foundry foreman in fifty that could take a cupola and run off a heat successfully. If you speak to them about melting iron, they will tell you that they have an old melter that has melted iron for twenty years, and knows all about melting iron, and is doing the best melting that is done around this 104 lOUNDTNO OF IRON. part of the country. The old melter is generally a man whose father was a melter, and whose grandfather used to own a foundry, and all he knows about a cupola and melting iron was handed down to him by tradition from his grandfather. If you go on to the scaffold when the cupola is being charged, you will find the old melter standing at the charging door of the cupola with a look of mysterious wisdom plainly depicted upon his countenance. Every piece of iron is handed to him by his helpers and he throws it into the cupola. If the helpers chances to throw a piece of iron into the cupola, the old melter will take his bar and roll it over or twist it around a little ; if he does not move it around with his bar, and their is one dull ladle of iron in the heat, it is all laid to that particular piece of iron that was not charged right. The old melter lights his fire and charges the iron at a certain time every day, regardless of wind or weather. The lire is not half burnt up one day and the bed is all burnt up the next day, the result is, that on one day the blast has to be on for half an hour before any iron can be melted, and the next day the iron will be down in five minutes after the blast is on, and so dull that it cannot be used. If you ask the old melter why the cupola melts slow, or why the iron is dull, he will tell you that he has attended cupolas for twenty years, and they are liable to take those kind of spells any time — a cupola won't do to bet on, boss ; or he may squint one eye, give you a knowing look, and remark that we are going to have a change of weather ; I can see it in the cupola, for the changes in the atmosphere always affects the melting of iron. If the owner of the foundry hears that his neighbors are melting ten lbs. of iron to one lb. of fuel, he tells the old melter about it, and wants him to do the same. The old melter declares that iron cannot be melted ten to one, and that there is not a foundry in the country doing it ; but if the boss insists FOUNDING OF IRON. 105 that it must be done, the old melter goes to work at it and will do as well as his neighbor, and probably a little better. If an accurate account is kept of all the coal or coke charged in the cupola for a year, and compared with the coal or coke bought and delivered in the yard for the same year, the boss will probably find that he is short two or three hundred tons. If he asks the old melter what has become of this two or three hundred tons of coal or coke, the old melter will declare that he only used one lb. of fuel to ten lbs. of iron, and that the account he has given is correct, for he weighed all the fuel that went into the cupola except a few little pieces that he put in to fill up the holes in the bed before he commenced charging, which he did not bother about weighing. If the old melter takes a day, the whole shop must lay off", for the cupola is a mystery, and no one dare undertake to run off a heat except the old melter. Thus it goes on from time to time, and the old melter is the Lion of the foundry. PRACTICAL AND SCIENTIFIC MELTER. The practical and scientific melter, is the melter who understands his business, and attends to his business ; he chips out his cupola, and daubs it up in proper shape ; he puts up the iron bottom, and sees that it fits close and solid, and is properly supported ; he puts in the sand-bottom, and sees that it is packed solid and even, and has the proper pitch, without any hills or hollows in it ; he puts in the front so that it never blows out, and he sees that the spout is in proper shape ; he always has the tapping-bars drawn down to a sharp point, so that he can tap with ease, and have the tap- hole large or small ; he has his bod-clay thoroughly 106 FOUNDING OF IRON. mixed, and his bod-sticks always handy, and in good shape. When he wants to stop-up, he takes the bod- stick and sees that there is a bod on it in proper shape ; he then puts the bod right over the tap-hole and gives it a sudden downward pressure, and stops the iron with ease. He puts in the shavings to light the fire with, and sees that they are properly spread over the sand- bottom, so as to light the wood evenly — the wood is cut short and split, and every piece is laid in the cupola, in the proper shape, so as to give the fire the best possible chance to burn, and light the coal or coke evenly ; he selects a few small pieces of coal or coke, that will light easily, and puts them in on the wood, he then puts in the bed. K the cupola has a good draft, he puts in all of the bed before the fire is lit; if the cupola has a poor draft, he only puts in part of the bed before the fire is lit, and the balance' after the fire has got thor- oughly started. He sees that the bed is evenly burnt and level on top, before the iron is charged ; he charges the iron compactly together, so that it will get the good of all the heat frOm the fuel ; he sees that every charge of iron is level and even on top when all in ; he sees that every charge of fuel is properly distributed over the iron, so that it will melt the next charge of iron properly, and at an even temperature ; he increases or diminishes the amount of coal or coke, in the bed, or between the charges of iron, at the rate of twenty-five or fifty pounds at a time, until he finds the exact amount required ; he increases or diminishes the amount of iron on the bed, or in the charges, at the rate of one hundred pounds at a time, until he finds the exact amount of iron that can be melted in that par- ticular cupola, with the smallest percentage of fuel ; he then continues that charging without a,ny variation ; if he gets in a poor lot of fuel, he may increase the bed and charges of fuel a few pounds; or, if the fuel is extra good, he may decrease a few pounds, but always FOUNDING OF IRON. 107 with caution and safety he watches the direction the wind blows, and notes the effect that a north, south, east or west wind has upon the draft of his cupola, and he lights his fire accordingly, so as to have the bed burnt as near alike, every day, as possible ; he inspects the blast-pipe and tuyeres, every day, to see that there are no holes in the pipe through which the blast may escape, and to see that the tuyeres are in proper shape, so that the blast will not escape up behind and through the lining, in place of through the stock ; he notices the exact effect of the blast upon the cupola, and he knows when he is not getting enough blast, and at once com- plains to the foreman, or engineer ; he looks around the shop, toward the last of the heat, and sees or asks the foreman how much more iron is wanted ; he then looks into the cupola, and if he thinks there is not enough iron in to pour off with, he throws in a little more, be- fore the stock gets too low to melt it. The practical and scientific melter does everything according to rule, and not by guess, and the foundrymen can depend upon him having good hot clean iron, every day, if it is possible to make it in his cupola. SMART-ALIC MELTER. The Smart- Alic melter is generally a very pompous and very important man in his own mind : he is always ready to give his opinion on everything, and more espe- cially on the cupola. He will tell you all about the cupola he was running before he came here, and what good luck he had with it. He will tell a new molder all about how well he gets along here, and he may tell him about that bad heat he had the other day when the engineer let the belts on the fan get loose, and he had no blast. He is always full of business and flying 108 lOUNBING OF IRON. around in a hurry, especially when the boss happens to be around. He picks out the cupola and daubs it up in a hurry, and gets out of it as quickly as possible, because it is a dirty job, and he says that it needs a new lining, anyhow. He puts up the iron bottom, and it may be twisted or warped a little, and will rock on the prop. He never wedges it or puts in an extra prop to make it solid, for he says the sand bottom makes that all right. The stock in melting may hang a little and come down with a lurch, and rock the iron bottom on the prop and crack the sand bottom and let the iron run out around the edges of the bottom ; Smart- Alic then jumps around and swears at that damned old crooked bottom — we ought to have had a new one long ago — and every one gets around the cupola with a bucket of water, a shovelful of sand or a ball of clay, and the bod sticks. Every one tells how it ought to be stopped ; they never think of taking off the blast ; the iron is melting all the time, and before they get it stopped from running out through the* bottom, it is running out at the tuyeres. Some one halloos, tap out the iron running out at the tuyeres. Smart- Alic then rushes around, grabs up the tapping bar, jabs it into the front in a hurry, and probably he will knock out the whole front and the iron runs out all over the floor, and finally the bottom has to be dropped. He puts in his sand bottom, and will probably ram it so hard in spots that the iron will not lay upon it, but will boil and cut up the sand, and will make a dirty iron, if it does not cut through and run out ; or he may have it so soft in spots that the iron will run through it, or so low on the back side that the iron will not run out at the front. He takes shavings to light the fire with up to the charging door, and throws them in ; it does not make any difference whether they are spread over the sand bottom or not, for they will burn, anyhow. He puts the wood in in long pieces, for he says the cupola has a FOUNDING OF IRON. 109 good draft and it will burn a long piece of wood just as well as it will a short piece, and there is no use of cut- ting it. He throws the wood in from the charging door, on its end, and it may dig a hole through the . sand bottom and let the iron run out. Smart- Alic will then fly around and swear that the melter that run that cupola before him, let the iron run out and burnt the iron bottom full of holes, and he cannot keep the iron in it without a new iron bottom. One-haU' of the wood will be above the coal or coke after the bed has been put in. That is all right ; the wood put in that way gives the fire vent and makes it burn better ; he says that little bit of wood that is above the coal or coke does not cost anything. He does not care if the fire is all on one side of the cupola, for he says that the blast will soon fix that after it is put on. If he is told that he is using too much fuel and he must use less, he will reduce it by taking four or five hundred pounds off the bed, and one or two hundred pounds off each charge of fuel, the first slap. If he is told that it might be better to put the iron in the cupola in larger cliarges, he will add another ton or two of iron on the bed, and will increase each charge of iron fifteen or twenty hun- dred pounds, the first slap. This way of decreasing the fuel or increasing the charges of iron is generally a failure, and the result is dull iron. Smart- Alic will then strut around the shop, pull down his vest, and tell you that he knew that cupola would not make hot iron charged in that way, for he has studied and watched it close, and knows just what it will do ; and it won't make hot iron with any less fuel than he is using ; and if you want to melt with less fuel, says he, you must get a new cupola, for that darned old thing is played out, anyhow. He never pays any attention to whether the wind blows from the north, south, east or west, because he does not melt iron by the way the wind blows, but by a fan blast, and 110 FOUNDING OF IRON, that fan will make just as much blast if the wind blows from the north as it will if the wind blows from the south ; he would never have any trouble in melting if the engineer would keep the belts, on the fan, tight, and give him a good blast. He never looks at the blast- pipe to see if there are any holes in it through which the blast may escape, because that is not his business ; and he has too much to do now, for all the wages that he gets, without fooling around an old blast-pipe. He never looks at the tuyeres to see if the blast escapes up back of or through the lining, for it is no use, for he put them tuyeres in right when he lined up, about a year ago, and he knows that they are all right. He charges the cupola so irregularly that he cannot tell any- thing about whether he has enough blast or not, but he is eternally growling about not having any blast, and his growling becomes an old song, and the foreman, or the engineer, never pays any attention to him. He never sharpens the tapping-bars, but has them blunt on the end, and in tapping he shoves the old bod into the cupola instead of cutting it away, and the iron forces it back into the hole and stops the iron from running out ; he takes the bar and jabs it into the hole and works it around, and will probably knock out the front ; he will then swear that that sand is not fit to put in the front with, because it cracks and crumbles when the heat strikes it ; he says that old spout is good enough for to- day, for he is a little behind time and cannot fool around making a new spout every day; he never pays any attention as to how his stopping-clay is, until he wants to use it, then he finds that it is too dry and he throws a little water on it and mixes it up in a hurry and has it wet and dry in spots ; he has his bod-sticks laying around anywhere, and he seldom has a bod on more than one stick at a time ; when he wants to stop-up, he takes the bod-stick, flourishes it around, the bod drops off into the ladle of iron, and he rams the stick into the FOUNDING OF IRON. Ill tapping hole, the iron flutters and squirts out around the stick, and some one tells him that he has no bod on that stick, then he flies around and makes two or three un- successful attempts to put on a bod in a hurry ; he tells every body to stand back and give him a chance — that they will crowd up around that cupola until they all get burnt some of these times ; he will finally get a bod on, and get the cupola stopped-up, after the ladle has run over, and the iron runs all over the floor, or the bod-clay may be so wet that it cannot drop oft* the stick, and in stopping-up he will shove the bod up under the stream, the iron shoots out over the bod and burns his hands, he drops the stick and swears that those stopping-sticks are too short, and he must have some new ones, for he is not going to get burnt every day stopping-up. The foreman makes out his estimate of how much iron he wants that day, and gives the estimate to the melter to charge by ; Smart- Alic looks at it, and says to himself, well, we had five hundred pounds too much iron yester- day, and I am not going to have five hundred pounds too much to-day to lug out and pour in the pig-bed, so he charges five hundred pounds less than he is ordered to do, the result is, that they are five hundred pounds short that day ; the foreman thinks that he made his estimates too low, and the next day he adds a little to make up for what he was short the day before ; he then gives his estimate to the melter ; Smart-Alic looks at it and says to himself, that he was short five hundred pounds yesterday, and he is not going to be short to-day, sohe charges five hundred pounds more than he is ordered to do, the result is, that they have ten or fifteen hun- dred pounds more than is wanted, and no one is to blame. Smart-Alic does not have all of these troubles, every day, but he has some of them most every day ; he will have from two to three bad heats a week, and will blame them on the blast, on the atmosphere, on poor fuel, on that old, worn out cupola ; and, in fact, he 112 FOUNDING OF IRON. will blame the bad heats on most anything but himself. I have not made up my mind yet whether the old pro- fessional melter, or the Smart- Alio melter, is the worst, but I have made up my mind that they are both a nui- sance about a foundry. N. B. — Smart- Alic, with all his faults, has his good redeeming qualities, for he is generally a philanthro- pist ; he often supports one or two families out of the dump ; he helps the poor fire-brick manufacturer to sell his brick, and the poor dealer in fire-sand and fire-clay tells the foundryman that he has got such a good melter ; if it was not for Smart- Alic, the poor patent cupola man would die of starvation, but if Smart- Alic was to " pass in his checks," the engineer and the flux- man would be happy. HOT-BLAST CUPOLAS. Not only have the foundrymen endeavored to imitate the blast furnacemen in the adaptation of limestone as a flux for their cupolas, but they have also attempted to imitate them in the adaptation of a hot-blast for their cupolas, and with this view several different styles bf cupolas and ovens for heating the blast have been constructed, but they have generally been abandoned as a failure. The best hot-blast arrangement for a cupola, that I have seen, is that represented in fig. 19, in which D D represent the cupola in which the stock is charged and the iron is melted ; B JB represent the arched flue that connects the top of the cupola with the ovens E E, and through which the heat passes into the oven from the cupola i), as shown by the white darts ; it then passes down around the coil of the pipes C C, Fig. 19. FOUNDING OF IRON. IIB and enters the flue or stack A at the bottom. The cold blast is forced through the pipes C C, which are heated by the flame from the cupola, and when the blest enters the cupola at the tuyeres it is hot. This pair of cupolas were erected by the Foundry Company of Jagger, Tread- well & Perry, of Albaiiy, N. Y., with a view of saving fuel and improving the quality of the iron melted, but experience proved them to be a failure, for more power was required to force the blast through the coils of pipe, and it took some time to get the pipe hot enough to heat the blast, so that the heat would be half off before the blast became hot enough to do any good. The coils of pipe were expensive to keep up, and although some little fuel was saved in the cupola, yet it was not enough to pay the expense of keeping up the pipe, and this hot-blast arrangement was abandoned as a failure. Several hot-blast cupolas have been built, wdth large stacks on top of them filled with coils of pipe, and the pipe heated by the flame and waste heat from the cupola ; the cold blast was forced in at the top of the coil of pipe, and as it passed down through the pipe it became hot before reaching the tuyeres. This hot- blast arrangement was like that of fig. 19, expensive to keep up, and has generally, been abandoned. Several attempts have been made to. draw hot air from the stack of the cupola and again force it in at the tuyeres. To do this, the supply pipe for the fan or blower has been connected with the stack just above the charging-door, and the hot air dra\vn from the cupola and forced through' the fan or blower and into the tuyeres. This arrangement has in every instance been a failure, for the hot air from the cupola soon heats the fan or blower, and burns off' the belts and ruins the machine. Whether or not a hot blast will improve the quality of pig-iron when remelted in a cupola, has not been de- termined ; but it has been satisfactorily demonstrated 8 114 FOUNDING OF IRON. that the blast cannot be economically heated with the waste heat from the cupola, for, in order to heat the blast, we must pass it through coils of hot pipe, and the heat from the cupola is not intense enough, before the blast is put on, to heat the pipe, and the cold blast must be put on in order to create a flame from the cupola and heat the pipe ; and when the cold blast is passing through the pipe to the cupola, it takes some time to heat the pipe wdth the flame from the cupola, and in melting a few tons of iron the pipe would not become sufficiently hot to heat the blast before the iron would all be melted ; and even if the pipe were sufficiently heated to heat the blast, toward the last of the heat, the often sudden cooling of them when the cupola was dumped, would soon break and crack the pipe, which would have to be replaced with new ones to avoid the escape of the blast ; and the advantage gained by this kind of a hot- blast will not pay the expense of keeping up the pipe. The only way that the blast can be thoroughly heated and the pipe prevented from breaking, is, to heat the pipe in an oven and keep them continually hot, the same as at a blast furnace. This arrangement cannot be eco- nomically applied to small foundries where the cupola is only in blast for two or three hours each day ; but it might be applied in large foundries where one cupola after another is put in blast, so that one or more cupo- las are kept in blast all day. For small foundries a hot blast might be arranged by building a furnace and closing up the ash-pit, and blowing the cold blast into the ash-pit and allowing it to pass through the tire be- fore entering the cupola. This arrangement would be a success so far as heating the blast, but the question would be; whether volume enough of blast could be forced through the fire to supply the cupola without putting out the tire or using too much fuel to heat the blast. I do not know that this arrangement has ever FOUNDING OF IRON, 115 been tried for a cupola, but it has been tried for a rever- beratory furnace, with anthracite coal, and works suc- cessfully; and some of our enterprising foundrymen might do well to try and apply it to their cupolas. RE YERBERATORY FURNACES. The reverberatory furnace is the best furnace for melting and mixing iron on the large scale for foundry purposes. They are next to the crucible for making a good homogeneous foundry metal, and are used in all foundries where heavy work is made that requires a good homogeneous iron and great strength such as cannon, rolls for rolling mills, house and bridge beams, etc. Iron melted in the reverberatory furnace is cleaner than iron melted in a cupola, and it will flow into the mold like molten lead, and will make a casting more free from blow holes ; but in foundries where light work is made and hot fluid iron is more of an object than the strength of the castings, the reverbera- tory furnace has, as a general thing, been replaced by the cupola furnace, which has the advantage over the reverberatory furnace of melting iron faster, hotter, and with less fuel ; but the iron in the reverberatory furnace is not melted in contact with the fuel as in the cupola, but it is melted by the flame or gases from the fuel, and it does not take up the sulphur and other im- purities from the fuel. as it would do if melted in con- tact with the fuel. There are several different kinds of the reverberatory furnaces, but they only differ in the minor points of their construction, and all agree in the one principle of throwing a highly heated flame against the iron. These furnaces are constructed of flre-brick laid in fire-clay,, and the whole furnace is surrounded with cast-iron plates bound together with 116 FOUNDING OF IRON. cross ties or rods, and they are sometimes built of common brick and lined with tire-brick, and the whole- bound together by iron cross-ties and binders. But the furnace surrounded with the cast-iron plates is the best and the cheapest furnace in the long run. In the reverberatory furnace the bridge wall that separates the hearth and the grate-bars is from six to ten inches high above the hearth and twenty or twenty-five inches above the grate-bars. The grate-bars are three or four feet long and the grate or fire-place is as wide as the furnace and sometimes wider. A large slide door is put in just back of the bridge wall for charging the iron ; this door may be in the top of the furnace or on one side. The iron to be melted is all piled in the furnace on the hearth just back of the bridge wall before the fire is lit. The stack of the furnace should be high enough to give a good strong draft, and it should be fitted with a damper on top of it so as to regulate the draft. The walls of these furnaces should be very thick so as to be as bad a conductor of heat as possible. All the cracks and openings around the door and in any part of the furnace should be carefully stopped up with clay or loam when the furnace is in operation, so that no cold air will be admitted into the furnace except through the grate and fire. In the working of these furnaces a great deal depends upon the bridge wall between the hearth and the fire, for if the bridge wall is either too high or too low the heat will be wasted and hot iron cannot be made. The best fuel for the reverberatory furnace is the bituminous coal. Anthra- cite coal or coke is used in some parts of t e country as fuel for this class of furnaces, but it is not near so good as the bituminous coal. When the anthracite coal or coke is used, the ash-pit of the furnace is closed up and a mild blast turned into the ash-pit so as to supply oxygen more rapidly and create more flame from the IS 5^ A fi %. i g «■» y A <-^ ^LMAM r. M^r: Fig. 20. FOUNDING OF IRON. 117 fuel. When the anthracite coal is used, a large amount of fine ashes will be carried over the bridge wall and deposited on top of the molten iron ; these ashes will prevent the iron absorbing the heat, and where it is desirable to make very hot iron, these ashe^ should be occasionally skimmed off through an opening made in the furnace for that purpose. Wood is not at all qualified for use as a fuel in this kind of a furnace where no mineral coal can be obtained ; charcoal may be used as a substitute for it. Fig. 20 represents a sectional view of the reverbera- tory furnace that is generally used in foundries for melting iron. In this furnace A represents the grate or fire-place ; B the hearth upon which the iron is melted; C the tap-hole at which the iron is drawn out of the furnace, and D the door through which the refuse is taken out and the furnace repaired. The hearth B is generally put in with fire sand or a mix- ture of sand and fire clay, or it may be built of brick and nearly covered with fire sand or clay. The pig- iron or iron intended to be melted is piled on the hearth just back of the bridge w^all, and as it melts it fiows into the basin or hollow in the centre of the furnace where it remains until it becomes sufficiently heated to run into the molds. It is then drawn out at the tap hole C into ladles for small work, but for large work it is generally run from the furnace through a trough directly into the mold. In foundries where large quanties of iron is melted for heavy castings and it is desirable to mi:jr the iron thoroughly by polling it, the hearth of this furnace is made as wide as the grate or fire-place, and the fire-place may be five or six feet wide, but in foundries where only small amounts of iron is melted, and it is desirable to make the iron very hot and fluid for light work, such as malleable castings, the hearth is only two or three feet wide, while the fire- place is five or six feet wide. By reducing the width 118 FOUNDING OF IRON. of the hearth in this way, the heat is more concentrated on the iron and will make a hotter and more fluid iron. Fig. 21 represents a sectional view of another style of reverberatory furnaces, that is commonly used in foun- dries where light castings is made, and it is desirable to make very hot iron. In this figure, A represents the grate, or fire-place, in which the fuel is burned ; the iron intended to be melted is piled on the hearth of the furnace, just back of the bridge wall, through a large door in the side of the furnace, as indicated by the dot- ted lines ; this door is raised and lowered by a lever on top of the furnace, as shown in fig 21. In charging the iron in the furnace, it should be piled on the hearth eighteen or twenty inches back from the bridge wall, so as to cause the flame from the fuel to dip over the bridge wall, and strike the iron. As the iron is melted on the hearth it flows down into the basin C, and all the dirt or sand on the iron is left on the hearth from where it may be removed through the large door. After the heat, the molten irpn is held in the basin, at the bottom of the stack, where the heat is the most intense, until it is sufficiently fluid to run into the molds. It is then drawn out into ladles, or may be run from the fur- nace directly into the mold. This furnace is consid- ered to be a better furnace for making hot iron than the furnace, fig. 20. In constructing this furnace, the grate, or fire-place is generally made five or six feet wide, and the flue, at the bottom of the stack, is only two or three feet wide, so as to concentrate the heat upon the iron, and also to concentrate the iron, so as not to expose so much surface of molten iron to the ox- idizing action of the flame. Less fuel is required for this furnace than for any of the other kinds of reverber- atory furnaces. Fig. 21, FOUNDING OF IRON. 119 YOUR NEIG-HBOR AND YOU. Some foundrymen wonder how it comes that their neighbor can sell castings so much cheaper than they can and make a living. They say that they buy stock as cheap as their neighbor, and they do not pay their men any higher wages, and they have got just as good molders, and they put up as large a day's work as their neighbor's niolders do ; their patterns do not cost any more than they do in any other foundry, and their neighbor must be losing money and will break up in a short time. They never look at the cupola ; they think that is a foundry fixture that is alike in every foundry, but there is just where the difference comes in. Your neighbor sees that his cupola is constructed right, and charged and worked right, and by so doing he will undersell you and still make a good profit. If a prac- tical foundryman was to travel through the country and examine the cupolas in use at the present time, he would be surprised to see how unscientific and how little judgment has been used in their construction. He will find cupolas sixty inches in diameter, and only seven or eight feet high. The next cupola will be twenty inches in diameter and fifteen or twenty feet high. The next one will be built like a big tub, larger at the top of the stack than at the bottom of the cupola, and the heat all escapes up the stack. The next one will only have one or two small tuyeres ; and the next one w^ill be all tuyeres. One cupola will have scarcely any blast, and the next one will have three times as much blast as it ought to have. The next one will be an old cast-iron stave cupola with one-half of the staves broken, and more blast escaping through the caisson than is going up through the stock. The next one has not been lined for ten years or more, and the lining is all cracked an 1 shaky, and one-half of the blast escapes 120 FOUNDING OF IRON, up between the lining and the caisson ; and so it goes all through the country, and yet we boast about the advancement we have made in the construction of fur- naces and the melting of iron. There is no more judg- ment used in the selection of a melter than there is in the construction of cupolas. Foundrymen generally believe in cheap labor, and they consider the melter an unimportant man, and they will hire some cheap man that does not know enough about the laws of combus- tion to start a fire in a cook stove, and they will give him full charge of the cupola. He gets a few instruc- tions when he first takes charge of the cupola, and after that he is allowed to do as he pleases and use his own judgment, and he has no more judgment than a shoe- maker's hog. He will pick out the cupola three times as much as he ought, and then daub on two or three inches of mud ; and he will generally have to put in a few new bricks every day. He has to put in three or four feet of new lining (just above the tuyeres) about once a month. He will use twice as much wood in starting the fire as is necessary, and throw it all on one side of the cupola. He will put the bed in too high, and use twice as much fuel between the charges of iron as is necessary. This extra fuel has all to be burnt up before the iron can come down to the melting point. The nuid is too heavy to hang on the brick lining, and breaks loose and settles down over the tuyeres, and prevents the iron from melting, and it takes two or three hours to run off a heat that should be run off in one hour ; and there is more wastage of iron, more fuel has to be used under the boiler, and there is more wear and tear of the machinery and belts. This poor, cheap melter will use and cause to be used twenty dollars worth more stock, in the melting of a few tons of iron, than is really necessary to be used. Yet the foundry- man never notices any of these things ; all he thinks of is the twenty-five or fifty cents less per day that he FOUNDING OF IRON. 121 pays this man than he would have to pay a good man. The melter has the dirtiest and most disagreeable job about the foundry ; in the winter he has to stand in the cupola and pick it out, and the draft of the cupola makes it the coldest place about the foundry. He has to handle the cold mud with his hands to daub up with. The cupola often stands outside, and he has to be out in all kinds of weather to charge up. In the summer he often has to go in and pick it out before it is cold, and he has to be around where it is the hottest, charg- ing and tapping out — and a good man is not going to at- tend a cupola unless he gets better pay than he can get for more agreeable work. The melter is generally the poorest paid man about the foundry, and he is often the poorest man about it. This should not be so ; for the melter is the most important man about the foun- dry. It makes no difference how much care a molder may take to make a nice, clean mold ; he cannot make a nice casting without good, hot, clean iron ; and it makes no difference how much expense the foundry company may go to for the latest improved fan or blower, or for the best cupola ; for the best cupola in the world will not do good melting unless it is charged and worked right, and no man should have charge of a cupola but a good, sober, sensible man, that has some judgment of his own. The melter in a small foundry should receive as much wages as a molder, and the melter in a large foundry should receive more wages than a molder. If he is not worth as much or more than a molder, he is not worth having about the foun- dry. No foundry foreman is a competent man to have charge of a foundry who does not thoroughly under- stand the working of a cupola and the melting and mix- ing of irons. He should be able to take the cupola and run off a heat as well as the melter. No foundryman, who has not thoroughly investigated the management of cupolas and the melting of iron, has any idea how 122 FOUNDING OF IRON, much money can be and is wasted by the improper con- struction and management of cupolas. If foundrymen would pay more attention to their cupolas, they would be able to compete with their neighbors in the market ; for a diligent study of the construction and manage- ment of cupolas and furnaces will not only enable the foundryman to obtain the most valuable iron from a given material, but it will enable him to modify his products in accordance with the state of the market and the wants of the times. Perhaps in no other branch of business is rational and skilled management so indis- pensable an element of success as in the foundry busi- ness. Hence the difference of success between differ- ent individuals where locality and material have been equally favorable. Neither education nor superior means is a guarantee of success. A vigorous applica- tion of the reasoning faculty alone will insure success in a close contest of competition. SCRAPS. If a poor molder loses his work, he will always swear that the iron was dull or dirty. If a good molder loses his work, he knows why He lost it, and remedies the evil next time. If the cupola makes dull iron, or melts badly, the melter will blame it upon the engineer, and swear he had no blast. If the cupola makes dull iron, or melts slow, the en- gineer will swear that the melter has packed the stock too closely in the cupola, and that he is giving it more blast than it had last heat. The melter that melts ten to one, is a fraud. Never throw a stone at a melter or foreman of a Cin- cinnati foundry, for you might hit a tuyere inventor. The patent cupola that will melt a forty-pound hand- FOUNDING OF IRON. 123 ladle full of iron every six seconds from the time the blast goes on until the bottom is dropped, and give one hundred and twenty men each four hundred pounds of iron out of twenty ton charges, is the best cupola ou^. The best tea-kettle molder in the United States works in nine hollow-ware foundries out of every ten ; but the Cincinnati foreman that made eighty-four tea-kettles every day far six weeks, and never lost one of them, is the boss of them all. The melter that always has trouble with his cupola, and always blames the cause of the trouble on some one else, is a fraud. There is no telling how much fuel or fire-clay a melter uses when he has a pile to go to. That darn'd old worn-out cupola will be as good as a new one, if you put a new lining into it and keep it up in proper shape. That molder who made the big cannon that they drew the ball into with a yoke of oxen, and then took the oxen out through the touch-hole — he is dead; and any moulder that comes around and represents himself to be the man, is a fraud. MALLEABLE-IRON CASTINGS. The term malleable-iron means an iron from which the carbon has been removed by the operation of pud- dling and boiling, fnd is a wrought-iron. The term malleable-iron castings means an iron that has been cast into any desired shape, and then malleableized by removing the carbon by a process of annealing, which consists in burning off the whole or a part of the carbon combined with the iron from which the castings were made. In the manufacture of malleable-iron castings, the first 124 FOUNDING OF IRON. object is to get the proper kind of pig-iron, for all iron is not suitable for making malleable-iron by the process of annealing. From the states in which carbon exists in cast-iron, this has been classified into three princi- pal sub-divisions. The first is the gray metal, or num- ber one foundry pig, in which the carbon is not com- bined with the iron, but is in the graphitic state, and may be seen in large flakes when the iron is broken. These flakes are sometimes called tissue and black-lead. The second division is the mottled cast-iron. In this iron the carbon is partly combined with iron and partly in the graphitic state, which gives the iron a spotted or mottled appearance. This iron is also called forge, or mill-iron. The third division is the white cast-iron. In this iron the carbon is combined with the iron, and is unseen. This iron is also called forge, or mill-iron. The gray iron, or number one foundry -iron, is the best iron for ordinary foundry castings, because it con- tains the most carbon, and is softer, and will remain fluid longer than either the mottled or white irons ; yet it is not the best iron for malleable castings, for the carbon in it is not combined with the iron, and in con- verting the castings into malleable -iron, the carbon is extracted from the iron without melting the castings, and if this class of iron is used, the castings will be full of small holes after they have been malleableized, and they will not have the required strength. The iron that will make the best malleable castings is the white cast-iron, for in this iron the carbon is com- pletely combined with the iron, and when it is ab- stracted from it by the annealing process, it leaves a perfectly sound and smooth casting. But in using this iron for malleable castings, another trouble arises. The iron contains so little carbon that it will not retain its fluidity long enough to be run into light castings ; and almost all of the malleable castings are very light, so that this class of iron cannot be used. FOUNDING OF IRON. 125 And as the gray iron, or number one foundry iron, contains too much carbon, and the white iron too little carbon, the best iron for malleable castings must be the mottled iron, which is between the two extremes. And this is the iron that is always used for malleable-iron castings, and none but the very best brands of cold- blast charcoal mottled iron will produce a good mallea- ble casting. The brands of iron that are considered the best for malleable castings are the Baltimore and Chi- cago irons. The^e irons each have their local names, but among the foundrymen they are generally known by the above names. The numbers four and five Bal- timore irons are generally used together, as they pro- duce the best castings ; and the numbers five and six Chicago irons are generally used together, as they produce the best castings. These irons are graded differ- ent, so that the numbers four and five Baltimore irons are the same as the numbers five and six Chicago irons. These irons are not clear white in the pigs, but are slightly mottled, and contain just enough carbon to give the iron the necessary fluidity, while in the cast- ings the iron is a clear white. There are several other brands of iron that are used for malleable castings, but as I have not melted or w^orked any of them, I cannot give their names, nor the numbers that produce the best castings. Iron for malleable castings may be melted in a cupola, or in either of the reverberatory furnaces (figures 20 and 21). But the iron melted in a reverberatory furnace always produces by far the best castings, for the iron is not melted in contact with the fuel, as in the cupola, and it is not deteriorated by the impurities contained in the fuel. There is also the advantage that, should the iron con- tain too much carbon, part of it may be removed by the oxidizing action of the flame. As most all malleable castings are very small,' they 126 FOUNDING OF IRON. are generally molded in snap-flasks, with green sand, from metallic patterns, or match-plates. The castings, before they are annealed, are as hard and brittle as glass, and they must be handled with care to prevent breaking. These castings are put into a tumbler, or rattle-barrel, where they are cleaned of all adhering sand, and become polished by mutual friction ; and to have them anneal properly, it is very essential that they should be thoroughly cleaned. The cleaned castings intended for conversion into malleable iron are next packed into iron boxes with alternate layers of fine iron scales from rolling-mills. The boxes are then closed at the top by a mixture of sand and clay, and all the cracks are carefully closed up to prevent the admission of air. The boxes are next put into the annealing-oven, where they are subjected to a white heat, not sufficiently hot, however, to melt the boxes. They are kept at this heat for a week or more, and then allowed to cool off gradu- ally. After the castings have been properly annealed, they are covered with a film of oxide of different colors, and resemble in appearance that kind of Champlain iron ore called peacock ore. These various colors of the oxide are a sign of good malleables. This adherent oxide is removed from the casting by another passage through the rattle-barrel, and the process of malleable- iron making is finished. Powdered iron ore is sometimes used in place of the iron scales, but it is not near so good as the scales, for it contains more or less silica and earth, which, at the temperature of the annealing-oven, will fuse and form a slag, or cinder, and prevent the oxidizing action on the castings. For this reason the scales are to be pre- ferred, and care should always be taken to keep them as free from earthy matter as possible. In every heat or annealing operation, the scales part with some of their oxidizing properties, and before they are again used they must be pickled and re-oxidized. This is FOUNDING OF IRON. 127 done by wetting them with a solution of sal-ammoniac and water, and mixing and drying them until they are thoroughly rusted, when they are again ready for use. The annealing-boxes were formerly made of soft iron, but at the present time they are mostly made of hard iron, the same as the castings are made of. The hard iron boxes become annealed the same as the castings, and will last longer than the soft iron boxes. These boxes are generally made about twenty inches long by fourteen wide and fourteen deep. They are set one on top of another in the annealing-oven, but are never set more than two high. The lower one has a bottom cast in it, but the top one has no bottom, and is merely a frame set on the lower box. These boxes only last a few heats, and the small boxes are said to last longer than the large ones. There are several different kinds of annealing-ovens in use at the present time, and some very important improvements have been made in the construction of these ovens in the last few years. The best one in use at the present time is one with a fire on each side of it, and so arranged that the flame from the fuel does not enter the oven or strike the boxes. This oven is not allowed to cool off, but is kept hot all the time, and at one end there is a door through which the annealing- boxes are removed while at a white heat, and are replaced by cold ones. The door is then closed, and the boxes heated to the required heat. This kind of an oven is the most economical one in use, for it requires less fuel than any of the othors, and is not injured by expansion and contraction in cooling and re-heating, as the other ovens are. When annealing the castings in the oven, care should be taken to not have the temperature of the oven too high, or the heat too prolonged, or the castings may be burnt and hardened after they have been soft- ened. After the castings have been thoroughly decar- bonized by annealing in the oven, they are virtually a 128 FOUNDING OF IRON. commercially pure iron, and are the same as wrought- iron without fiber, and fiber may be imparted to them by rolling or hammering. Yet these castings without fiber are sometimes equal to the best wrought-iron for strength, and may be bent double when cold without breaking them. The manufacture of malleable-iron by the process of annealing is older than is generally supposed. It appears to have been known in the year 1700, and malleable castings were then made upon the same principle as they now are, although it is doubtful whether the process had been brought to the same per- fection in those days as at the present time. THE FOUNDING OF ALLOYS. A DESCRIPTION OF THE SOURCE, PHYSICAL CHARACTER AND USES OP ALL THE METALS AND ALLOYS EMPLOYED IN « THE MECHANICAL AND USEFUL ARTS OF LIFE. 9 THE FOUNDING OF ALLOYS. The term alloy means a compound of two or more metals, but when one of the metals entering into the compound is mercury, the compound is then termed an amalgam. The founding of alloy seems to be older than the founding of iron; for although we read in the Scriptures of iron and brass, yet we do not find any account of the founding of iron, while we do find accounts of the founding of alloys, both in the Scriptures and ancient history. In the description of Solomon's tem- ple, in the Scriptures, we find that all the pillars, chapi- ters, wreaths, panels, bases, and the twelve oxen and the bason or sea that set upon the twelve oxen, were all made of bright brass ; and all the vessels for the temple were made in such great abundance, that the weight of them could not be found out ; and all these castings for the temple were cast by Hiram, in the plain of Jordan, in the clay ground. From this descrip- tion it would seem that these castings were made either in green sand or loam, and it is probable that the pro- cesses of molding them were the same as the processes of molding in use at the present time. At the time of the building of the temple by Solomon, the Israelites do not seem to have understood the founding of alloys to the same perfection as the other nations around them ; for, when about to build the temple, Solomon sent to Hiram, King of Tyre, to send him a man cunning in 132 METALS AXD ALTAlVS, the working of brass ; and in one part of the Scripture it is recorded that the King of Tyre sent him a man who was a widow's son, of the tribe of Naphtali, and his father was a man of Tyre, and a worker in brass. And in another part of the Scriptures it is recorded that he sent him the son of a w^oman of the daughters of Dan, and his father was a man of Tyre, skillful to work in gold, silver, brass, iron, etc. Whether tlie King of Tyre sent Solomon' any more men to work in brass, is not stated ; but as was customary in those days, Hiram, the King of Tyre, seems to have gotten all the credit ^ -for doing the work. The founding of alloys seems to have been brought to gi'eat perfection by almost all of the ancient nations, for all their implements of w^ar, such as the sword, spears, shields, etc., were made of bronze, and all their tools, ornaments, etc., seem to have been made of alloys of different metals. Bright brass seems to have been a favorite metal in the days of Solomon, and it is prob- able that the ancients valued the bright and showy alloj-s more than the less showy metal, iron. The alloy bronze seems to have been used by all the ancient na- tions for weapons, shields, edged tools, etc. The ancients understood the art of hardening and tempering bronze to perfection, so that the want of steel was not so se- verely felt as we may be inclined to believe at the pres- ent time. The ancient Mexicans understood the art of converting bronze into edged instruments, in a high degree. The bronze of the ancient Greeks consisted chiefly of copper and tin, but some of their bronze in- struments have been found that also contained gold, silver, lead, zinc and arsenic. The ancients appear to have been acquainted with only seven metals ; at the present time we are acquaint- ed with lifty-one or fifty-two ; yet the metals to which the application of useful metals most peculiarly belongs at the present time, were most all known to the an- METALS AND ALLOYS. I'do cients, although we have fifty-one or fifty-two metals at the present time. Only about fourteen of them are used in the foundry of metals or in the useful arts of life. The majority of these fifty-one or fifty- two metals are merely chemical curiosities of no practical value whatever. METALS AND RECIPES FOR ALLOYS. Of all the known metals in use at the present time, iron and platinum are the only metals that bear weld- ing and forging well, and iron or steel is the only metal that admits of being hardened beyond that degree which may be produced by simple mechanical means, such as hammering, rolling, etc. Yet all the metals, with the exception of platinum and its kindred metals, admit of ready fusion ; and their fusibility offers an easy means of uniting them, and many of them com- bine with other metals with great readiness, and by mix- ing two or more of these metals by means of fusion, an alloy may be formed that is of an entirely diff'erent na- ture from any of its constituents, and by the process of founding alloys, may be cast into any desired form. The malleability and ductility of these metals, as well as their hardness and brittleness, is often increased by alloying with each other, and these qualities are often turned to many usv3ful and varied purposes. The ready fusion of these metals also aff'ords a ready means of uniting two or more metals by the fusion of a third metal, by the process of soldering. Some of these metals will unite with others in almost any proportion, and forms a perfect chemical mixture which, in many cases, produces a superior metal to either of its constituents, while in others the chemical affinity is limited, and they will only unite in certain proportions, and 134 METALS AND ALLOYS. when mixed beyond these proportions, the alloy is only a mechanical mixture, and often forms an infe- rior metal to either of its constituents. I have given several recipes for the formation of alloys by mixing these different metals ; but in using these or other re- cipes in forming alloys, the founder must not be guided entirely by the recipe, but he should use his own judg- ment as well, for the metals may contain certain im- purities, or, as it is termed,^ be a poor metal, which will produce different results ; and in order to produce good alloys, a long practical experience is as essential as good recipes ; for a man who has not had practical ex- perience in forming alloys, can no more produce a per- fect alloy from a recipe than a school-boy can produce perfect writing from his first copy. ALLOYS OF IRON. All admixtures added to iron make it more fusible than when pure, although thje admixtures added may not be a metal. Lead can be alloyed with iron in small quantities. A small amount of lead causes iron to be soft and tough, but too much causes it to be extreme cold-short. Copper, if alloyed with iron, causes it to be extreme red-short, and more than one per cent, of copper will cause it to be cold-short ; but a small amount of copper will increase the strength of iron when cold. Arsenic imparts a beautiful white color to iron, re- sembling silver, but it makes it very brittle. Tin, when alloyed with iron, makes a beautiful fine white metal, and when the tin and iron is alloyed about half-and-half, the alloy is as hard as steel ; but it can- not be forged. Chromium, alloyed with iron, makes an alloy that is METALS AND ALLOYS. 135 as hard as diamond ; but it is very difficult to make this alloy. Silver, alloyed with iron in small quantities, causes the iron to be very hard and brittle, and very liable to corrode. Gold can be alloyed v^ith iron in any amount. It causes the iron to be more yellow and tough. This al- loy is principally used as a solder for small iron castings. Carbon makes iron more fusible. From one to two per cent, of carbon, added to iron, makes hard cast- iron, and from five to six per cent, makes number one foundry iron. More than five or six per cent, of carbon causes iron to be very brittle, and less than one per cent, of carbon causes iron to be very hard and brittle. Sulphur causes iron to be both hard and brittle, either when hot or cold, and it causes molten iron to be short- lived. Fuel with sulphur in it should not be used for melting iron in contact with the fuel. Phosphorus is very injurious to iron. One-half of one per cent, will cause iron to be very hard and brittle when cold, but it imparts a brilliant and white color to iron more perfectly than any other metal. Silicon makes iron brittle and hard. It has a similar effect on iron to phosphorus, but it is not near so injuri- ous to the iron. All cast-iron contains more or less carbon, sulphur, phosphorus, and silicon, and as these substances pre- dominate, they form hard or soft, strong or brittle irons ; and as all anthracit3 coal and coke contain more or less of these substances, the anthracite or coke iron is less pure and more variable than the charcoal irons; and on account of the uncertainty of the amount of these impurities contained in cast-iron, it is very difficult to make an alloy of iron and other metals with any cer- tainty as to the result, and for this reason alloyed iron is very little used. 136 METALS AND ALLOYS. PLATINUM ALLOYS. Seven parts platiimiu, sixteen parts copper, and one part zinc, make an alloy tliat is almost eqnal to gold. Ten parts platinum and one part arsenic form an alloy that is fusible at a heat a little above redness. It can be cast into any desired shape, and the arsenic evaporated and the platinum left in its pure state, and infusible. Two parts platinum, three parts silver, and ten parts copper, make an alloy that is very elastic, and does not lose its elasticity by annealing, and it will bear ham- mering when red hot, or may be roiled and polished. Tin is sometimes alloyed with platinum, but the tin increases the fusibility of the platinum, so that the alloy is little better than an alloy of tin and lead. Platinum is but little used in forming alloys with other metals. GOLD ALLOYS. Gold leaf contains from four to ten grains of copper and silver to the ounce of leaf. The gold plate used by dentists contains about eighty parts gold and twenty parts copper. Five parts gold and live parts copper make a gold with a reddish cast. Ten parts gold, four parts copper, and one part silver, make a rich reddish-colored gold. Eighteen carats gold of a yellow tint is composed of sixty parts gold, eleven parts silver, and nine parts copper. Eighteen carats gold of a red tint is composed of sixty parts gold, seven parts silver, and thirteen parts copper. kSixteen carats gold is composed of sixty parts gold, METALS AND ALLOYS. 137 ten parts silver, and twenty parts copper. This makes a very tough and springy alloy that is sometimes used for springs instead of steel. Fifteen carats gold of a red tint is composed of ten parts gold, one part silver, and four parts copper. Fifteen carats gold of a yellow tint is composed of twenty parts gold, seven parts silver, and five parts copper. This makes a very fine alloy that is much used by jewelers. Gold with a green tint is composed of sixty parts gold and ten and one-half parts silver. Gold with a gray tint is composed of forty parts gold and fifteen parts silver. Gold with a blue tint is composed of equal parts of gold and steel filings. Solder for eighteen carats gold is made of forty-eight parts eighteen-carats gold, four parts silver, and two parts copper. Solder for twenty-two carats gold is made of forty- eight parts twenty-two carats gold, four parts silver, and two parts copper. Solder for fifteen carats gold is made of twenty-four parts fifteen-carats gold, ten parts silver, and eight parts copper. In the above solders yellow brass is sometimes used instead of copper, as it makes the solder more fusible. When copper is used, a little zinc is sometimes added, but it is better to add the zinc in the shape of brass. SILVER ALLOYS. Nineteen parts silver and one part copper form an alloy for silver plate. Fifteen parts silver and four parts copper form a harder alloy than the above. It is also used for silver- plated spoons and trinkets. 138 METALS AND ALLOYS, The silver coin of the United States is composed of nine parts silver and one part copper. Silver solder is composed of thirty-three parts silver, fifteen parts copper, and two parts old brass. Hard silver solder is composed of six parts silver and two parts old brass. Soft silver solder is composed of four parts silver to two parts old brass. This alloy is the one commonly used for soldering silver. Some add a little arsenic to it to make it more fusible and white, but when arsenic is added care should be taken to avoid its fumes, both when making the solder and w^hen using it. The old brass is used in these alloys to avoid wasting the zinc. Silver is sometimes soldered with the common solder used for soldering tin, but it will not receive a polish, and a nice job cannot be made with it. The alloys of silver are but little used in founding, for they all expand at the moment of solidification, if they contain much silver. G-ERMAN SILVER ALLOYS. German silver is composed of eighty parts copper, twenty parts nickel, and thirty-three and one-half parts zinc. The best quality of German silver is composed of one hundred parts copper, fifty parts nickel, and fifty parts zinc. The white copper, or packfong of the Chinese, which is the same as the German silver of the present day, is composed of forty-one parts copper, seventeen parts nickel, thirteen parts zinc, and two and one-half parts iron. A very hard German silver is made of eight parts METALS AND ALLOYS. 139 copper, four parts zinc, two parts nickel, and one part iron. This alloy is very tenacious and ductile. A still harder German silver is made of sixteen parts copper, eight parts zinc, four parts nickel, and three parts iron. The finest quality of German silver that is made is composed of sixteen parts copper, eight parts nickel, and seven parts zinc. Ten parts copper shavings and four parts arsenic, arranged in a crucible in alternate layers, and covered with a layer of common salt, make a beautiful white alloy that is almost equal to silver. In making this alloy care must be taken to avoid the fumes of the arsenic. BISMUTH ALLOYS. Fifty parts bismuth, twenty-five parts lead, and twenty-five parts tin, form a very fusible alloy, which melts at 200« Fahrenheit. Fifty parts bismuth, thirty parts lead, and twenty parts tin, form a still more fusible alloy, which melts at 190O Fahrenheit. Eight parts bismuth, three parts lead, and two parts tin, form an alloy that melts at 212° Fahrenheit. Eighty parts bismuth, fifty parts lead, forty parts tin, and ten parts type-rietal, constitute a harder but less fusible alloy than any of the above mixtures. Soft solders and pewters are made of four parts bis- muth, eight parts lead, and six parts tin ; or two parts bismuth, two parts lead, and four parts tin. All the above alloys must be cooled quickly to avoid the separation of the metals. In order to get the metals thoroughly mixed, they should be repeatedly melted and poured into drops. , ^ 140 METALS AND ALLOYS, BRASS ALLOYS. A very good brass is made of sixteen pounds of cop- per, eight pounds of zinc, and one-half pound of lead. The lead should be added after the copper and zinc have been melted together. These proportions of the different metals make the best brass that can be made with zinc and copper. For very light castings the lead should be omitted, as it makes the alloy less fluid ; but in heavy castings, it makes them more solid and clean. Button-brass consists of twenty-four parts copper to fifteen parts zinc. Red-brass is made of nine parts copper and one part zinc. Red-brass made at Hegermuhl consists of five and one-half parts copper and one part zinc. Brass that bears soldering well consists of sixteen parts copper and six parts zinc. Brass for ship-nails consists of twenty parts copper, sixteen parts zinc, and two parts iron. Red sheet-brass is made of nine parts copper and two parts zinc. Brass for sheathing, bolts, fastenings, etc., is com- posed of six parts copper and four parts zinc. This composition forms an alloy that may be rolled and worked at a red heat. Brass for pumps, and machinery requiring great tenacity, is made of thirty-two pounds copper, three pounds tin, and one pound zinc. Brass for gear-wheels, to have teeth cut in them, is made of thirty-two pounds copper^ three pounds tin, and two pounds old brass. If it is desirable to have the wheels harder, a little more tin may be added. An alloy for turned and finished work is made of thirty-two pounds copper, four pounds tin, and three pounds old brass. For nuts of coarse thread, one-half pound more tin may be added. METALS AND ALLOYS. 141 As more tin is added to alloys of copper and zinc, or copper and old brass, the alloy becomes harder. Razors have been made of an alloy of thirty-two parts copper, five parts tin, and five parts zinc. The best white hard metal for buttons is made of sixteen parts copper, two parts zinc, and one part tin. LEAD AND C O P P E R A L L O Y S. Seven parts lead and sixteen parts copper makes a very cheap alloy, but it is rather short, and easily broken. Two parts lead and eight parts copper makes a red- colored alloy that is very tough. A red-colored and ductile brass is made of two parts lead and sixteen parts copper. Ordinary pot-metal is made of six parts lead and sixteen parts copper. This alloy is very brittle when hot, but tough when cold. The alloys of copper and lead are all very brittle when hot. More than one-half pound of lead cannot be alloyed with one pound of cop- per, for the copper will not unite with the lead, and the lead will ooze out in cooling. Alloys of lead and copper are very little used. Lead and copper alloys have a bluish, leaden hue when much lead is used, and are principally used on account of their cheapness. BRONZE ALLOYS. A bronze in imitation of gold may be made of 45.5 parts copper, 3.5 parts tin, and one part zinc — fifty parts. Bronze medals are generally cast of an alloy of fifty 142 METALS AND ALLOTS, parts copper and 2.8 parts tin. This alloy is very- hard. A softer bronze for medals than the above is com- posed of forty-six parts copper and four parts tin. Ancient bronze nails were made of forty parts copper to one part tin, and were very flexible. Soft bronze is composed of eighteen pounds copper to two pounds tin. Hard bronze is composed of twenty pounds copper to five pounds tin. The ancient bronze mirrors are said to have con- tained sixteen parts copper to from seven to eight parts tin. At the time of Louis XIV of France, a period when the art of casting statues was much cultivated in France, siatues were cast of an alloy of 30.6 parts copper, 0.11 parts tin, two parts zinc, and 0.6 parts lead. The statue of Louis XV is cast of 82.4 parts copper, 10.3 parts zinc, four parts tin, and 3.2 parts lead. The bronze of the ancient Greeks consisted chiefly of copper and tin, but was frequently alloyed with arsenic, zinc, gold, silver and lead. All their shields and weap- ons of war were made of bronze, as well as coin, nails, kitchen utensils, etc. All the ancient nations seem to have understood the art of tempering bronze and copper, and the ancient Mexicans understood the art of converting bronze into edged instruments in a high degree, but the art of tem- pering and hardening bronze and copper has been lost to modern nations ; but as.we understand the working of iron better than the ancients, and have steel, an alloy of iron and carbon, which the ancients did not have, we do not miss this art much. METALS AND ALLOTS. 143 BELL-METAL ALLOYS. One hundred and forty-four pounds copper, fifty- three pounds tin, and three pound iron, is said to make a superior bell. Iron, copper and tin do not unite well, if each is added separately to the other, but if tin-plate scraps are melted in a crucible together with tin, and then this tin and iron alloy added to the molten copper, it will unite readily. Another alloy that is highly recommended is com- posed of 53.5 parts copper, 6.11 parts tin, 2.13 parts lead, and 3.9 parts tin. This alloy has a good, sonorous sound, even if the mold is not thoroughly dry. House bells are made of four pounds tin to sixteen pounds copper. Soft musical bells are made of three pounds tin to sixteen pounds copper. Common bell metal consists of fifty pounds copper to firteen or twenty pounds tin. The silver bells of Rouen, France, consist of forty pounds copper, five pounds tin, three pounds zinc, and two pounds lead. Too much tin causes bell metal to be brittle. The gongs or cymbals and tam-tams of the Chinese are composed of forty pounds copper to ten pounds tin. To give these musical instruments their proper tone, they are plunged in cold water while hot, after being cast ; cooling in water deprives the metal of almost all its sound. It is tempered and very slowly cooled, which imparts to it that peculiarly powerful sound. If bell metal is suddenly cooled, it becomes less dense and hard, and is increased in malleability ; but the tone of the metal is decidedly impaired, and bells ought never to be cast in damp molds. When bells are cooled suddenly they should jbe re-heated and tempered by cooling slowly. 144 3IETALS AND ALLOYS, TYPE-METAL. Six parts lead and two parts antimony form a very hard and brittle alloy used for small type. Eight parts lead and two parts antimony form a softer alloy that is used for larger type. Ten parts lead and two parts antimony form an al- loy that is still softer, and is used for medium-sized type. Fourteen parts lead and two parts antimony form an alloy that is softer than any of the above alloys, and is used for the largest sized type. A small amount of tin is sometimes added to the above mixtures, and some type-founders add one or two per cent, of copper. Both of these metals improve the quality of the type, when used in small quantities. Forty parts lead, eight parts antimony, and two parts tin, form an alloy that is used for stereotype plates. Six parts lead and two parts tin form coarse solder, used by plumbers. This alloy melts at about 500*^ Fahrenheit. Two parts lead and four parts tin form the fine sol- der used by tinners. It melts at about 350° Fahrenheit. LEAD ALLOYS. Ninety-four parts lead and six parts antimony form an alloy that may be rolled into sheets, and is a little harder than pure lead. This alloy is much used for sheathing for ships. Twenty-four parts lead and four parts antimony form an alloy that is used in place of babbitt metal for filling small boxes and bearings. METALS AND ALLOYS. 14D Twenty parts lead and four parts antimony form an alloy that is a little softer than the above, and is used for the same purpose. Either of these may be hardened by the addition of more antimony ; but care must be taken to not use too much antimony, for it will cause the alloy to lose its fluidity, and it cannot be run into the boxes. All alloys of lead and antimony are rendered more fluid by melting them under a covering of oil. Five parts lead and five parts tin make a beau- tiful white alloy, used for organ pipes. The mottled, or crystalline appearance, so much admired in the pipe, is caused by using an abundance of tin. One hundred parts lead and two parts arsenic form an alloy from which drop-shot is made. Eighteen parts lead, four parts antimony, and one part bismuth, form an alloy that expands on cooling. This alloy is much used for metallic patterns for snap- moldings. SPELTER-SOLDER ALLOYS. A good solder for copper and iron is composed of three parts zinc and four parts copper. A softer solder that is used for ordinary brass work is composed of equal r)arts of zinc and copper. A very hard but fusible solder is composed of two parts zinc and one part copper. This solder is so hard and brittle that it can be easily crumbled in a mortar when cold. The two first solders are first alloyed and cast into ingots. The ingots are allowed to cool in the mold and then re-heated nearly to redness upon a charcoal fire, and are broken up on the anvil, or in a mortar, into a finely granulated state, for use. 10 146 3IETALS AND ALLOYS. HARD-SOLDER ALLOYS. The following metals and alloys are usually used as solder in the art of hard-soldering : Fine or pure gold, rolled or beaten into sheets, and cut into shreds, or small pieces, is used as the solder for soldering chemical vessels made of platinum. Silver solder, composed of four parts silver and two parts yellow brass, is much used for hard soldering. The brass is used in this solder, so that the opera- tor can tell when the solder is fused, by seeing the blue blaze caused by the burning of the zinc. This solder is either rolled into thin sheets, and cut into small bits for use, or is granulated while hot. The gold solder, the composition of which is given under the head of gold alloys, is rolled into thin sheets and used for soldering gold alloys. Gold soldering is generally done with the blow-pipe, as the work is sel- dom large enough to require the Ibrazier's hearth. Pure copper, in shreds, is sometimes used for solder- ing iron. Spelter-solders, granulated while hot, are used for soldering iron, copper, brass, gun-metal, German-silver, and sometimes for gold and silver alloys. As a cheap substitute for silver solder, the white, or button-solders are commonly employed for the white alloys, such as German-silver, gun-metal, etc. The flux most generally used in hard-soldering is borax. In fact, there is very little hard-soldering done without the aid of this flux. It is generally granulated, and used in the dry state for large or heavy work, and for small work it is generally used in solution with water. METALS AND ALLOYS, 147 SOFT-SOLDER ALLOYS. The soft solder used by plumbers, called sealed solder, is composed of two parts tin and four parts lead. This solder melts at about 450^ Fahrenheit. The common solder used by tinsmiths is composed of four parts tin and two parts lead. This solder melts at about 350<^ Fahrenheit. The bismuth solder is composed of seven parts bis- muth, five parts lead, and three parts tin. This solder melts at about 225° Fahrenheit. All the tin and lead solders become more fusible the more tin they contain. Thus, one part tin and ten parts lead melt at about 550° Fahrenheit, while six parts tin and one part lead melt at about 375° Fahren- heit ; and all the tin, lead and bismuth solders become more fusible the more lead and bismuth they contain. The fluxes used in soft soldering are : borax, sal-am- monia, chloride of zinc, common resin, Venice turpen- tine, tallow, and sweet oil. Those most commonly used for ordinary work, are : common resin and chloride of zinc. BABBIT ANTI-FRICTION METAL. This metal is made of one part copper, three parts tin, two parts antimony, and three parts more tin are added after the composition is in the molten state. This composition is called hardening, and when the metal is used for filling boxes, two parts tin are used to one of hardening. The above alloy constitutes the best anti-attrition metal in use, but on account of its expense it is very little used. The anti-attrition metals com- monly used are principally composed of lead, antimony and a little tin, but they are not near so good as the above 148 . 3IETALS AND ALLOYS. FLUXES FOR ALLOYS. The best flux for alloys of copper and tin is rosin. It should be added when the metals are almost melted. Another good flux is sal-ammonia. In using this flux the copper is usually melted first and the flux added. When it is in the mushy state, after the flux has been put in, the zinc and tin are then added. A good flux for old brass is common rosin-soap. It should be added in small lumps and stirred down into the metal when in the molten state. In forming alloys of diff"erent metals, the molten met- als should always be kept under a covering of black glass or pulverized charcoal, to prevent oxidation. BLACK FLUX. Black flux, as it is commonly called, is composed of seven parts of crude tartar, six parts of saltpetre, two parts of common bottle glass, and by some a small amount of calcined borax is added. These ingredients are first finely pounded and mixed together, and then gradually heated in an iron pot or ladle so as to burn them together. Care should be taken to not overheat the mixture ; and as soon as it is thoroughly melted and mixed together, it should be removed from the fire and allowed to cool. After it has cooled it is finely pulverized and sifted, and is then ready for use. It has a great affinity for moisture, and should be protected against it by being placed in glass bottles and the bot- tles corked up until wanted for use. This is the most powerful flux that can be made. It is but little used in forming or fluxing alloys, but it is principally used by assayers in assaying of diff'erent kinds of metallic ores. In these assays the quantity of black flux used 3IETALS AND ALLOYS. 149 varies according to the quality of the ores, but the amount generally used is about an equal amount of ore and flux. The ore is first roasted and then finely broken up and mixed with the flux, and the whole is then rapidly heated in a crucible. If the flux does not make the slag sufficiently fluid to allow the metal to settle, a smalj amount of calcined borax is added, which makes the slag more liquid and permits the metal to pass to the bottom of the crucible. The crucible is then removed from the fire and the mixture either poured from it or allowed to cool in it. After it has cooled, the slag is knocked off with a hammer and a button of metal obtained. When using this flux the clay cruci- ble, without either coal or plumbago, is preferred, for the flux is very hard on a crucible that contains either of these substances. Black flux is used by some foun- drymen in melting the fine scrap sweepings from the floor, and dross and refuse from the crucibles, by melt- ing these in a crucible with black flux. They obtain considerable amounts of metal from them that would otherwise be lost. In melting this refuse with black flux, the common clay crucible should always be used. NATURE AND CHARACTER OF ALLOYS. Alloys of gold, silver and copper are generally supe- rior in strength to any of the more fusible metals, and may be forged either when red hot or cold. These three metals seem to unite in any proportions, and always form an alloy that is malleable when either hot or cold. Pure gold is but little used in the arts ; it is then too soft. It is generally alloyed with silver and copper, both to harden it and depreciate its value. Alloyed 150 METALS AND ALLOYS. I with copper, it forms gold of a red tint ; with silver, it forms gold of a green tint ; and alloyed with both cop- per and silver, it gives intermediate tints. Pure silver is but little used alone ; it is generally alloyed with a small amount of copper, which does not change its color, and greatly improves its malleability and working qualities. When gold, silver or copper are alloyed with the more fusible metals — lead, tin and zinc — the alloy is less malleable and ductile than alloys of gold, silver and copper. They are extreme red-short, and when heated to redness they will fly to pieces under the ham- mer ; and alloys of brass, bell metal, etc., must be treated with precaution, and should never be taken out of the mold while red hot. Alloys of two parts copper and one part zinc are very soft and malleable, and may be drawn by hammering, or easily cut with a file ; but an alloy of one part copper and two parts zinc is as hard and brittle as glass, and may be easily pulverized. An alloy of two parts copper and one part lead makes a soft, malleable metal, but is inferior to an alloy of copper and zinc. In alloys of one part copper and one part lead, the lead will ooze out in cooling. In alloys of one part copper and two parts lead, the lead will not unite, but will sink to the bottom when cooling. Alloys of six parts copper and one part tin make a very hard alloy, and the alloy gets harder and whiter the more tin is added. Alloys of tin and copper should not be too rapidly exposed to the air, for if a large per- centage of tin is used, it will strike to the surface and ooze out, or make hard spots in the casting. Alloys of zinc and lead cannot be made without the addition of arsenic, unless the lead is alloyed in a very small quantity. Alloys of zinc and tin are very hard and brittle, and are but little used alone. By the addition of copper to METALS AND ALLOYS. 151 alloys of these two metals, the alloy is rendered more malleable and soft. Arsenic makes all alloys hard and brittle, and is very dangerous to use. It is seldom used except to impart fluidity to the very infusible metals. Alloys of lead and tin are very malleable and ductile when cold, but at a temperature of about 200° Fahren- heit, they lose the power of cohesion and are exceed- ingly brittle. The alloys of tin and lead partake of the general nature of these two metals. They are soft and malleable when cold, even when a small amount of brittle antimony has been added. An alloy of six parts lead and one part antimony is very soft and malleable, but an alloy of three parts lead and one part antimony is very hard and brittle ; and an alloy of one part lead and one part antimony is harder and more brittle than antimony. FUSIBILITY OF ALLOYS. In forming alloys of the different metals, they do not combine with each other in their solid state (with the exception of mercury), owing to their chemical affinity being counteracted by the force of cohesion ; and in order to form combinations of them, it is necessary to liquify at least one of them, in which case they will unite, provided they have a chemical affinity for each other ; thus bell metal and brass is formed, when pieces of tin, or zinc, are put into molten copper ; and in the formation of alloys, of this nature, where one of the metals are more fusible than the other, the less fusible metal should be fused first, and the more fusible metals added either in the molten or solid state. As the fusi- ble metals are added, the temperature of the alloy should be reduced, to prevent oxidation, or burning 152 METALS AND ALLOYS. away of the fusible metals ; for this reason, it is better to add the more fusible metals in the solid state, as by so doing the temperature of the metals is decreased. Alloys are always more fusible than the less fusible metals, of which they are composed, and in some cases are more fusible than the most fusible metal they con- tain, as is the case in alloys of tin, lead and bismuth. Some founders, in order to have the metal thoroughly united, first fuse the metals together, and cast them into ingots and re-melt them for use ; this practice is bad, for in the after-fusion there is always more or less of the more fusible metal burnt away, and it is hard ta determine the proportions of the alloy, or to have any certainty as to the quality of the castings. In melting ingots, or scrap alloys, they should be fused as rapidly as possible, and at the lowest available temperature, se- as to avoid oxidation. Some of the metals are almost infusible ; and when heated to the highest heat, in a crucible, they refuse to^ melt and become fluid ; but any of the metals can be melted, by combination with the more fusible metals ; thus, platinum, which is infusible with any ordinary heat, can be fused readily, when combined with zinc, tin or arsenic ; this metal, by combination with arsenic^ is rendered so fluid that it may be cast into any desired shape, and the arsenic may then be evaporated by a mild heat, and leave the platinum, in its pure state, cast into any desired shape. Nickel, which barely fuses alone, will enter into combination with copper, forming German silver, an alloy that is more fusible than nickel and less fusible than copper ; this alloy is rendered the whiter, harder and less fusible the more nickel is added. The less fusible metals, when fused in contact with the more fusible metals, seem to dissolve in the fusible metals : rather than melt the surface of the metal, is gradually washed down, until the entire mass is dis- solved or liquified, and reduced to the state of alloys. METALS AND ALLOYS. 153 In forming alloys of brass, in furnaces where heat enough cannot be obtained to fuse \hQ copper sepa- rately, the alloy may be formed by heating the copper to the highest heat, and then adding the zinc or tin, in the molten state, so as not to reduce the temperature of the copper. In forming alloys with new metals, it is usual to melt the less fusible metals first, and then add the more fusi- ble metals, and mix them by stirring them well togeth- er ; the rod used in stirring them should be heated to redness, to prevent lowering the temperature or chil- ling the metal. In mixing alloys for bells, the alloy should be well stirred with an iron rod, well heat- ed, in which case part of the iron is dissolved, and com- bines with the alloy, and gives the bell a better tone ; » but alloys of brass, that are to be turned, or finished, should never be stirred with an iron rod, for the iron dissolved from the rod will cause hard specks in the alloy if not thoroughly mixed. In forming fine alloys, the alloy should be stirred with a rod of the least fusible metal contained in the alloy, or with a wood stick ; the wood stick, in many cases, is better than a metallic rod, for it causes the metal to boil slightly, and unite more thoroughly ; but the wood stick cannot be used in a small crucible, with only a small amount of metal. "When alloys are made that contain only a very small quantity of a metal that is difficult to fuse, as in pew- ter, it is scarcely possible to throw into the melted tin the half per cent of melted copper, with any certainty of the two metals being properly combined; and in forming this alloy, it is customary to melt the copper in a crucible and then add to it two or three times its weight of melted tin ; this dilutes the copper and makes an alloy, called temper or hardening. This alloy is very fusible and is melted in an iron ladle, and is added to molten tin, or lead, to give it the desired hardness, and form pewter. 154 3IETALS AND ALLOYS. The metal mercury will bring about triple combina- tions of metals, even when the metals have no chemical af- finity for each other, either when the metals are melted, or in the solid state, as in water-gilding, where the silver, copper, or metal intended to be gilded is first made chemically clean by washing in acids and water, and then rubbed over with an amalgam of gold containing about eight parts of mercury. This amalgam immedi- ately attaches itself to the metal, and it is only neces- sary to evaporate the mercury, which only requires a very low heat, and the gold is left firmly attached to the metal ; and it is only necessary to brighten it by burnishing. Water-silvering is accomplished in the same way, and iron or copper, and many other metals, may be tinned in the same way. An amalgam of tin and mercury is made so as to be soft and easily crum- bled. The metal to be tinned is cleaned in the same way as in gilding with gold, or by turning or filling, and the amalgam is then rubbed on and the mercury evaporated by heat. This process of tinning is called cold-tinning. Other pieces of metal can be attached to a metal that has been tinned in this way, by soldering. In the manufacture of tin-plate, the iron plate to be tinned is first scoured and made chemically clean. It is then immersed in a bath of pure molten tin, cov- ered with resin and tallow to prevent oxidation. The iron plate remains in this bath for a short time, and the tin unites, or becomes alloyed with the surface of the plate, and comes out of the bath perfectly coated with tin, and is called tin-plate. In this process the iron plate must be heated to the temperature of the molten tin before combination takes place. But by the aid of mercury the iron plate may be tinned at the atmos- pheric temperature. METALS AND ALLOYS. 155 BRASS FURNACES. Furnaces for the melting of brass and similar alloys may be bailt of common brick and lined with fire- brick ; but the best furnaces for this purpose are made with a boiler-plate caisson from twenty to thirty inches in diameter, and thirty or forty inches high. This caisson is usually set down in a pit, with the top of it only ten or twelve inches above the foundry floor. The ash-pit, or opening around the furnace, is covered with a loose wooden grating, which may be removed for tak- ing out the ashes. The iron caisson is lined with fire- brick, the same as a cupola. The lining is usually six inches or more in thickness. The- diameter of the fur- nace on the inside should not be more than four or five inches larger than the diameter of the crucible intended to be used in it ; for if the furnace is too large, more fuel and more time will be required to melt the metal. These furnaces are liable to burn out hollow around where the crucible sets, and to avoid a waste of fuel, they should be straightened up with fire-clay and fire- sand, and always kept as near straight as possible. These furnaces are sometimes 'built square on the in- side, but the square furnaces are not near so good, and require more fuel than the round ones do. A good brass foundry usually has three or more of these furnaces. They are generally of diff'erent diameters to suit diff'er- ent sized crucibles, and when it is desirable to make a large casting, that requires more metal than <;an be melted in one crucible, two or more furnaces are used to melt the metal. But when more metal is required for a casting than can be melted in three or four cru •- bles, the metal is then melted in the reverberatory fur- nace, or in the common iron foundry cupola. When melting brass in a cupola, the copper is usually charged and melted before charging the zinc or more fusible 150 ji/<:tals and alloys. metals, and in some cjisoh the zinc or tin is not pnt, into the ('npola. at all, but is melted in an iron ladle and added to tlie copper after it lias been dr;iwn out of the cupola. When the amount of brass to be inelt(Ml in a cupola is small, and the cupola has a good draft, the metal is usually melted without a blast; but when the metal amounts to several tons, a, blast is gc^ntn-aJly used. The swivel cui)ola (l^^ig. H)) is well adapted to the melting of brass, and is often us(m1 for that purpose. The co^innon brass furnace usually depends upon a natural draft, and the furnace is connected with the stack by a small iiue on the back side of the furnace, near the top. Thnu^ or more furnaces are usually con- nected with one stack, and each furnace is su])plied with a separate damper for regulating the In^it. WIumi the stack is not high enough to give the furnace a good strong draft, the ash-pit is closed uj) tight, and a mild blast turned into the pit ; for better melting ca,n be done by turning the blast int(» the pit and allowing it to lind its way up through the grates, than by putting the blast directly into the furnace by means of tuyeres. Tlu^se small brass furnaces are of easy construction ; but as a temporary (\vpedi(Mit almost any close fire may be used, including some of the common healing stoves, although it is nnich more convenient that the lire be open at the top, so that the contents of the crucible nniy be seen without removing it from the lire. Such stoves, however, radiate heat in a somewhat inconvenient nuin- ner, and to a nuich greater extent than the common brass furnace, which is lined with lire-brick or clay, and the lining con(tentra,tes the heat and economizes the fuel. The brass furnace is often used for melting iron in a. crucible, and they answer eipially as well for nn^lting iron as for brass, when the furnace has a good draft. Small amounts of brass are frinpiently melted in the ordinary blacksmith's lire; but there is consid- erable risk of cracking the crucible at the point exposed MliJTAIjS AND ALLOYS, 157 to tho blast. A wr()n