i Class Book. Q Copyright M". COPYRIGHT DEPOSIT. A TEXT BOOK ON WELDING AND CUTTING METALS BY THE Oxyacetylene Process WITH SIXTY-FOUR ILLUSTRATIONS THIRD EDITION-REVISED Copyrighted 1915 By C. H. BURROWS VULCAN PROCESS CO. MINNEAPOLIS. MINN. PREFACE TO THIRD I^UITKJX. It is diiU' ;i short time since the second eihtion was issued, and it is yratifyinii' to find that the stipply is nearly exliatised. I'here are many mechanics and atitot^enons welders who desire short, clear and ])ractical instructions on the snhject of oxy- acetylene welding- and it is the ])ur])ose of this book to fill thi'^ demaiul. A com])rehensi ve treatise on this subject would necessarily includi' much technical material that would be useless to the prac- tical man who wishes to ac(|naint himself with onl\ enough theor\ to thoroUjU^hh' master the performance of his duties, and for this reason we have excluded nearl\- everything of a strictly technical nature. The C"hai>ters on chemistrv. physics and metals are ot the most elementarv natiu'e. and cover in the plainest lani^uaj^e only the subjects that are vital to the welders information. At the same time the\' are suliicientlv explicit to i^ive him a tlu)rouL;h workiuL^- knowledi^e of the subjects that ])ertain t i his work. In compiling; these ])ai4es we ha\e cousulted the works on the .Manufacture and I'rojjerties of Iron and Steel, liy 11. 11. (,"ami)l)ell. U'he .\Ietallnri;\ of Iron and Steel, by I'.radley Stoui^hton, and Autogenous Welding, by ( iranzon and Rosem- berg : and some of the text relating to generators and welding has been c(\> and I'duxes The tlicory IV. Heat conductivity of different metals 'M V. Coefficients of expansion 3',i VI. Melting temperature of metals 'M) VII. Loss of pressure in pipes "U VIII. Loss of pressure by valves 71 IX. Cost of oxyacetyleiie cutting 114 X. Cost of cutting with oxygen jet 128 XL. Cost of welding with oxyacetylene torch 12S XII. C^iiaiitity of gas in cylinders 121) XIII. Variation of pressure in cylinders 129 XIV. Comparison degrees Centigrade and Fahrenheit 130 XV. Weight of oxygen di'ums 130 XVI. Consumption of gas — and cost of oxyacetylene welding 131 LIST OF ILLLUSTRATIONS. Figure Page 1 Broken locomoti\e cylinder 2 2 Same cylinder after welding 3 3 Building in gear teeth 5 4 Broken crank shaft 8 5 Same shaft after welding (5 Repairing broken pump case 10 7 Corner in chemical laboratory 15 S Phases of combustion 17 9 Oxygen plant 18 10 Generator room in electrolytic oxygen plant 19 1 1 Electrolytic cells 20 12 High ]iressure pump for gas compression 29 14 Typical carbide to water generator 4() 15 Modern oxyacetylene welding torch 50 16 Oxyacetylene torch 53 17 Straight line torch 53 18 Oxyacetylene cutting torch 54 19 Vulcan combination cutting and welding torch 55 20 Torch for welding machines 57 21 Automatic acetylene regulator 58 22 Automatic Oxvsen Regulator 59 23 Oxyaeetylene welding plant 60 30 Vulcan automatic, acetylene generator 61 31 Vulcan generator welding plant 63 32 Interior of Vulcan generator 65 33 Vulcun portable generator plant 67 23 Welding table 75 24 Combination welding table 76 25 Oxygen valve on oxygen drum slowly 78 26 Removable base for oxygen drum 79 27 Portable plant using dissolved acetylene 82 28 Portable generator plant 84 29 Convenient time card 86 34-35 Practical method of beveling thin pieces 90 36 Method of beveling thick pieces 71 37-38 Illustrating economy of beveling on both sides 91 39-40 Effects of expansion and contraction 92 41 The melting rod should not 97 42 Circular movement of torch for work of medium thickness 9 of the forest; there came to tlie familv of Jupiter and his wife. Juno, a little son whom the\ called \ ulcan. Little \ nlcan possessed i^reat ])(iwers and ability, but he was 11(11 a handsome child and bis mother |uno, who was disap])ointed in not ha\in^' a more beautiful son to i.;race the home of the ( iods, threw him down from I leaven. The infant (iod. falling; into the sea, was ri-scut'd and adopted bv Thetis, who kept him until he was nine years old. and then restored him to bis ])arents. hwen in his youth, the little (iod displayetl wt)nderful abilit\ at the tor_i;e and all metallic handicrafts ; and Jtipi^^^' recoi^iiiziu!.' this wonderful ability, made him the (iod of Fire. Tie late^" erected forj^es and work sho])s in which he emploved wonderfid one-eyed giants, called tlie Cyclops, to assist liim. In these shops he fabricated many i;real metal works, and one of his ])rin- t"i])al duties was to Foi-l^c thunder bolts for his father Jupitor. .Some claim his shops were on Mount Ktiia, where he used the heat of the volcano to work his forties. \ iilcan not only bad the ability to make the hottest tires and fort^e the most ditticult metal objects; but he was artistic b\ na- ure ; so when Jupiter wished to ])rovide the earth with the first mortal woman, \ ulcan fashioned lier out of clay, and the (lods animated the statue, ."^o his wonderful work is handed down to the present da\ in the i,''race and beauty of om* women. In honor of this Roman (iod. we have dedicated this book and named our jjrocess. wdiich develoi)s the hottest flame known, and causes the hardest metals to flow like wax. to X'ulcnn the (iod of Mre and Tatron < f all metallic handicraft! \ idcan I 'rocess ("o. WELDING AND CUTTING METALS BY THE OXYACETYLENE PROCESS OXY-ACETYLENE ^VELD1NG AND CUTTING FIG. 1. HHOKKX LOCOMOTIVE CYLINDER. This illustration shows the cylimler after the edges of the fracture liad been chipped for welding. The bar across the front and a similar bar across the rear was used to support a temporary grate, upon which the preheating fire was built. OXY-ACETYLEXE WELDIXG AXD CUTTIXG FKi. -2. LOCOMOTIVE CVEIXDKR AFTKK WKLDIXG. This illustrates the same cvliiuler shown in Fig. 1, with a new east iron piece welded in the fracture. Ordinarily the old piece is used to make the mend, hut in th's case the old piece had been destroyed by repeated attempts tu weld it in with thermit. 4 OXY-ACKTVLKNF, WKl.DI.Nii AND (TTTINC CHAPTER I. THJ-: USE OF THl-: OXY-ACETYLENE FLAME. The oxy-acetylene welding and cutting torch has become so popular in the last few years, that almost every issue of the trade papers in any liranch of work contains interesting accounts of new successes in the use of tliis powerful tool. The first ai)])licatio!i of the process, to coniniercial use, dates back to 1903, and its rapid growth in popularity is due to the ease and economy with wdiich its intense heat is applied to any of the metal trades, to join two pieces by welding, or separate them bv cutting without the stroke of a hammer. A notable example of the saving that may be effected by using this process is in the event of repairing a broken loco- motive cylinder shown in Fig. i. This cylinder had a piece broken out of the wall including a j)ortion of the flange. Previous attempts to weld this piece in place by other method?^ had proven disastrous, and resulted in making the fracture larger. The oxv-acetylene process was then brought into use, and in less than a day's time a new piece was welded in as shown in Fig. 2. The cylinder was rebored, drilled, and the job finished without removing it from the locomotive. A great saving in this case is credited to the fact that the loco- motive was put back into service in a comparatively short time, and the repairs were made without dismantling. The durability of this work is illustrated in fact that this cylinder was welded July loth, 1910, and is still in successful operation. Very often small pieces of a machine are broken off and lost, and in consequence the whole machine is out of use. In such cases it is not always necessary to have the missing piece with which to make rejiairs. but the missing portion may be built on with similar material melted from the welding rod. A good example of cases where this process is appliable is in building new teeth into a broken gear or sprocket wheel, build- ing u]) lugs or adding new material to ])arts that are badly worn. There are innumerable instances where the addition of a little metal will save much expense and long delays, and in the opera- TlIK ISK OF Till-; OXV ACKTVLKXK FLAME FKJ. ;•.. HriLDi.xd IN (ii:.\i; TKirrii. Ill this process tho old teeth aic not i('i|uiicil to iiial^e thi' iiieml, but new material is built u]> to form a new todtli. tion of contractors who are remote fi-oin tlieir base of su])|)lies. this sometimes amounts to (|uile an item. I^irge shipyards, railroad shops, contracting eng^ineers, as well as the smaller institutions, machine sho])s, boiler shops, foundries, i^aras^es and 'blacksmiths, all find this powerful flame indispensable for sure, quick and economical results. In proof of this statement it is well to cite experiments made at dif- ferent times, and in ditiercnt places by two of our foremost railway systems. These experiments were very carefully con- Iato whidi is shown bolted temporarily in the openinir of the pump case, was used as a grating to support the preheating fire. 11 CHAPTER 11. CHEMISTRY. Origin. The practical part of this science existed previous- to the theoretical ; and may be traced to Tubal Cain, the father worker of metals, but by degrees, as men began to think they also began to observe and theorize. Thinking men saw that a gross earthy matter, such as iron ore, became changed, by fire, into a hard metallic substance like iron, and upon these observations was built the most per- fectly systematized and exact science of the day. The Elements: — In the earth are millions of chemical com- pounds which are mixed together to form the air. the water^ the minerals or animal and vegetable life, and all of these com- pounds are capable of being separated into more simple sub- stances called "elements." For example water may be separ- ated into hydrogen and oxygen. Acetylene gas may be sep- arated into the simpler substances, carbon and hydrogen. In these examples the water and acetylene are chemical com- pounds, but the hydrogen, oxygen and carbon are elements and are not capable of being separated into more simple sub- stances. These elements may be separated into atoms, but all the atoms of any one element are alike in size and weight, and are composed of the same single substance as the element which it composed. Then we may say that an element is a single, simple substance, zcliich is dissimilar to, and incapable of bei)ig separated into, any other substance. Chemical Symbols. — The earlier chemists employed the signs of the planets to represent the metals; thus, silver was the moon, hence the expression "silvery moon," and the term ••lunar caustic" for silver nitrate. In the modern science each of the elements are represented by one or two initial letters called "svmbols" taken from the Latin name of the element. The symbol for iron is Fe, because the Latin name of iron is ferrum. That for oxygen is O ; for hydrogen is H ; for car- bon is C; and for calcium is Ca. 12 OXY-ACETYLKNK WKLUIXG AND CUTTING A table of about one-half of the known elements is arranged below showing- their symbols and atomic weights. TAHLH 1. Elements, Their Symbols and Atomic Weights. Arsenic As 7.") ManjiaiR'sc Mn 55 Barium - Ha 1.57.4 Molvhdenuiu Mo 96 Bismuth Bi 2(is Nickel Ni 59 Boron - B 11 .Nitroj^en N 14 Calcium Ca 40 O.vvireii O 16 Carbon C 12 i*lios|)horus P 31 Chlorine CI 35.5 I'otassium K 39 Chromium Cr 52 Silicon Si 28.4 Cobalt Co 59 Silver A^ 108 Copper Cu 63.6 Sodium Na 23 Fluorine F 19 Sulphur S 32 Gold - Au 197 Tin Sn 118.5 Hydrogen H 1 ritanium Ti 48 Iodine 1 127 Tungsten Wo 184 Irone Fe 5ti X'anadium V 51 Lead Pb 207 Zinc , Zti 65.4 Magnesium Mg 24 Chemical XofatioJi. — Ihe ])rinciples upon which the modern chemical notation is founded, is that each symbol indicates one or more atoms of the element it represents, thus C, C2, C27 indicate respectively, one. two and twenty-seven atoms of car- bon. Two symbols, placed side by side signifies that they are in close chemical union ; thus CO signifies a compound con- taining an atom of carbon and an atom of oxygen. L2 H2 signifies that two atoms of carbon are in chemical union with two atoms of hydrogen, forming one molecule of acetylene. When symbols are separated by the sign -f- it signifies that the atoms thus separated are not in chemical union to form one substance ; but are mingled and still exist as separate sub- stances, thus C2 H2 -J- O2 signifies that one molecule of acety- lene is mixed with two atoms of oxygen. A number placed on left of a group of symbols signifies that the whole group, as far as the next comma or plus -|-. is to be multiplied by it; thus 2 CO signifies that one atom of carbon and one atom of oxygen are combined to form one molecule of carbon monoxide and that two of those molecules are represented. The expres- sion H2 -\- 2 CO, signifies that two atoms of hydrogen are cllK.MlSTm' 1?. mingled with two molecules of carbon monoxide. llie sign = signifies a reaction or the result of mingling the atoms or molecules of different substances; thus, C2 H2 -{- O2 = TT2 + 2 CO signifies that if one molecule of acetylene becomes mingled witli two atoms of oxygen, there will be a chemical union in which two atoms of carbon unite with two atoui- oxvgen, forming two molecules of carbon monoxide and liber- ating the two atoms of hydrogen, which become mingled with the monoxide in an uncombined state. L'liriiiica! .Iffiiiity. — The attraction that causes elements to unite and form new substances, like water, acetylene or car- bon monoxide, and afterwards holds them together, is called chemical affinity. Some elements apparentK- have no affinity for each other, while others have a tremendous affinity. Some elements have an affinity for each other under certain in- fltiences, and will tinite forming- new sul)stances, but ttnder other influences this affinitv mav be destroyed and the sub- stances separated again into their original elements. Some of the more common influences which may eft'ect the affinitv of elements are heat, pressure and an electric current. To start chemical union it is sometimes only necessary to mix two substances together and they will unite and form a new substance. In this instance the elements are held to- gether by affinity. If this substance be mingled with another element under a different influence it may become separated and one of its elements unite with the newly added element. Take for instance acetvlene, which is com])ose(l of two atom> of hydrogen and two atoms of carbon held together by af- finity. Under ordinary conditions this union is stable and the acetylene may be mixed with oxygen without forming any new substance; but if heat or j)ressure is applied the car- bon will leave the hydrogen and unite with the oxygen. The result in case of applied pressure w(ndd l)e an explosion. llir .Itoiiiir Tlu'orx. — b"r(tm the foregoing it is observed that the uniou of atoms to form new substances is represented by a group of s\mbols, to which are attached various sign< 14 OXY- ACETYLENE WELDING AND CUTTING and figures. This group of symbols and figures is called a ■chemical formula. Let us study these formulas a little farther. Take for instance C2 H2, from the table of atomic weights we find the atomic weight of C = 12, and H ^ i ; then form this formula C2 H2 we may derive four thoughts : (i) the formula represents 1 molecule of acetylene. (2) one molecule of acetylene contains two atoms of carbon and two atoms of hydrogen. (3) one molecule of acetylene is composed of 24 parts by weight of carbon, and 2 parts by weight of hydrogen. (4) by weight, acetylene contains 26 parts. If the formula and atomic weights are known, the percentage of the composition ma\ be calculated as follows : C = 2 X 12 = 24 or 24 parts by weight of carbon H = 2 X I = 2 or 2 parts by weight of hydrogen. 26 parts bv weight in acetylene — = .923 or 92 ^yt carbon by weight 26 -= .o7(n)2 or 8', bvdrogen bv weight 26 J'aleiicc. — Atoms differ with respect to the number of atoms of other elements with which they will combine. This diflference in combining power is indicated by the term valence. Hie valence of an element is the niiinber of hydrogen atoms with zvhieJi its atom, will niiite, or replace. In water Ii2 O we find that one atom of oxygen wall unite with two atoms of hydrogen, therefore we say the valence of oxygen is II. The valence of carbon is IV. and of calcium is II. This means that one atom of carbon will unite with or replace four atoms of hydrogen, and an atom of calcium will unite with or replace two atoms of hydrogen. The application of valence is useful in writing formulas and CHEMISTRY 15 determinin.u' reactions. Thus, knowing- that the valence of car- bon is IV, we know each atom of carbon will miite with fotir atoms of hydrogen, and since the valence of oxygen is II each atom of oxygen will replace two atoms of hydrogen. Then in the reaction C2 H2 + O2 = H2 + 2 CO, as stated on page 14, we know the tinal H2 will unite with one more atom of oxygen and the final 2 CO will unite with two more atoms of oxygen. The complete reaction may be expressed as follows: C2 H2 + O2 = H2 + 2CO H2 4-0 = H2 O = one molecule water 2 CO -|- O2 = 2 (CO2) = two molecules carbon dioxide FIG. 7. CORNER IN CHEMICAT. T..\BORATOK'V. 16 OXY-ACETVLK.XI-: WKLDIXC; AND Cl'TTlXG Reaction. — The combination of elements to form a new snb- stance is called reaction. The term expresses a chemical union in which the resulting- substance has ])r()])erties ditterent from the elements which compose it. If the elements are minified without chemical union, there is said to be no reaction. Thus if finely i^round sul]:)hur be mixed with finely ground iron no new ])ro]^erties are produced, and we say no reaction has taken place, but if we heat the mixture a chemical action takes ])lace in which the elements unite to form a new' substance. Then we say there has been a reaction. When reactions produce heat. the\" have chemical energy. which can be transferred into other forms of work. Xot all reactions j^nxluce heat, biU some are accompanied bv a consump- tion of heat, and therefore use up energy, or rather they trans- form energy into chemical work. This heat energy is not lost for we can get it back by reversing the action. Coinhitstioii. — Combustion is a reaction in \vhich a fuel (com- bustible) unites with oxygen and produces heat. There are sev- eral elements that will react with oxygen in this way. l/'oremost among these are carbon, hydrogen and iron. When there is )usi the rig-ht amount of both oxygen and combustible to cause reac- tion, w'e have perfect combustion: but if there is an excess of either element, we have incomplete combustion. Incomplete con^- bustion always results in loss of heat. Flame. — When reaction is very ra])id. the heat developed may cause the gaseous elements to glow like white hot iron. These glowing gases are flame. I-dame has three distinct i)arts: the central or non-luminous part, where there is no combustion, but where the carbon l)egins to sei:)arate from the hydrogen; the second or luminous part, where the carbon is for a moment free and heated to a white heat ; and the exterior i)art, which is the hottest, and where combusion is complete. The foregoing is true with the ordinary flame where the oxygen is derived from the atmosphere and combustion takes on the exterior: but in the oxy-acetylene flame the oxygen is supplied in a pure state and mingled with the combustilile before it is ejected from the torch. This causes very rapid reaction and intense heat, and in this CHKMTSTRY 17 case, since the reaction is at the interior the hottest part is at tlie point of .i;:reatest ilhimination. It is easy now to understand of what iin])ortance is tlie form of the Inirner. and how we max mochfv it accordin^h- as we want Ht^ht or Iteat. If we wish Hght tlie carhon nuist he protected for a moment while it is in the ii'lowinij- state, hnt not long- enotigh for it to pass off itnconstimed. If. on the contrary, heat is desired, the carlron timst he linrned as rapidly as possible. FIG. s. PHASKS OF CO^rBT'STIOX IX OX V Ai ■1•:T^■ LKM-: FLAMK. Independent of the iiarts described on page 17, the oxy-acety- lene flame is divided into two very distinguishable parts, the inner flame, where the oxygen. su])i)lied by the torch, reacts with the carbon in the acet\"lene. producing carbon monoxide, and setting the h\(lrogen free; and the outer dame where the carbon iuon(»xide and Indrogen reacts with the oxygen supplied b\- the atmosi)herc. The inner tlanie is of a dazzling white, but the outer flame has a bluish tinge, due to the coiubusticju of hydro- gen, --urrounded by a yellow tlame due to the combustion of car- bon monoxide. The temperature, taken at the extremity of the white jet. is very nmch higher than that of an\ other flame, and is calculated to be ()3oo degrees F. To attain this lemperature without waste of gases, the torch must be constructed on highh scientific i)rinci])les. The size of the openings, the mixing chamber. i)ressures of gases, are all factors to be considered in its design. Ox^"GE^'. ( )xygen is an odorless, colorless, tasteless gas. It is mingled with nitrogen in the air. and ccimliined with hydrogen in water. It is united with nearly all the minerals in their native state, and is the most abundant element know 11 to us. At ordinar\ temuera- 18 OXY-ACETYLENE WELDING AND CUTTING tures it forms few chemical reactions, but when heated, is one of the most active elements, vigorously reacting- with hy- drogen and carbon, as well as their compounds in the form of gases. When oxygen reacts with an element the product is called an oxide, and the process is said to be oxidation. When iron is red hot it oxidizes very rapidly. The welder should therefore adjust his torch to procure a perfectly neutral flame, with just enough oxygen to consume the acetylene. Oxygen is prepared in a variety of ways, giving as great a variety in percentage of purity. For commercial purposes it may be made from chlorate of potash and manganese dioxide in the proportions of lOO pounds of the chlorate of potash to 13 pounds of the manganese dioxide. These two chemicals are first thor- oughly mixed, and then placed in a retort and heated. This lib- erates the oxygen, which passes off through washers to storage tanks. The cost of producing oxygen in this way, depends on the price of chemicals. With chlorate of potash at 93/2C per pound and manganese dioxide at 2;)4c per pound, the cost would aver- age 4c per cubic foot, including cartage, shop expense, etc. FIG. 9. OXYGEN PLAN. Usiii" CivstalliziNl Cliloiate of Potash and Manganese Dioxide. CHEMISTRY 19 Oxygen from .llr. — Oxygen may also be extracted from air. If, by means of comliined pressnre and cold, air be converted into a liquid, its two components may be separated by centrifugal force, or else tbe nitrogen may be allowed to evaporate leaving tlie liquid oxygen behind. No chemical processes are necessary for this separation because the elements are not combined. (;kxki{atoij wuum FIG. 10. \ Kl.llC'rii'Ol.VTIC O.WCKX 1"1..\.\T. Oxygen by Electrolysis of Jl'ater. — Oxygen and hydrogen are liberated when an electric current is passed through acidu- lated water. The apparatus first used for this ])ur|)ose consisted of a vessel containing water and having suspended therein, two test tubes with their open end submerged. Positive and nega- tive electrodes were placed just beneath the opening in the tubes, and when an electric current was caused to flow through the water between the electrodes, oxygen was liberated at the nega- tive pole, and hydrogen at the positive pole. These gases ascended and were gathered in the tubes. 20 OXY-ACKTYLKXK WKl.DlMi AND crTTlXG Although the prochiction of oxygen and hydrogen, hy the electrolysis (vf water, is one of the oldest electrochemical ex|)en- ments, it was not nntil recent years that the i)rc)cess was made economicalK' practical. There was considerahle difificnlty in developing an apparatus that would operate successfully in prac- tice. One of the hardest conditions to meet was the necessity of ahsolute safety. The ])ro1)lem has now heen worked out satisfac- torily so that large scale electrolysis of water is on a solid indus- trial hasis. Oxygen made hy this process is most pure and hest adapted to oxy-acet\ lene w elding. FIG. n. ELECTKOI.VTIC CELLS YOU (i KN KKATIXO OXYGKX. Hydrogen. Hydrogen is a colorless, tasteless, odorless gas. and the light- est substance known. By weight it forms ii per cent of water. and 8 per cent of acetylene. Hydrogen also exists in all living forms. It has a high chemical affinity for oxygen, and bnrn-^ CIIKMISTKV 21 with it at a temperature of about 4100 degrees F. When usef.' in the cutting torch with oxygen it is a very satisfactory fuel fo^ cutting the ferrous metals. Hydrogen is obtained in its purest form by the electrolysis of water. XlTROGEX. Nitrogen is a colorless, tasteless, odorless gas, foruiing "j l)er cent of air. It is of no Ijenetit to tlie nxy-acetvleue welder, jti fact it is a detriment since it does not supi)ort combustion but absorbs heat from the flame. TAHLK II. WEIGHTS OF GASES. „ ^ At 32° F and 14.7 lbs. pressure | of Specific Gas 1 Gravity Volume of one pound 1 cubic foot ' Weight of one cubic foot Oxygen 1.104 | 11.2056 Air 1. 1 12.388 Hydrogen .069 178.891 Nitrogen .972 12.7226 Acetylene .. .91 13.6126 .08925 .08073 .00559 .0786 .07346 Calcium Cakiudi-: Calcium is the metal that exists iu lime. Its symbol is Ca. Carbon, a solid but not a metal, occurs in the earth in crystallized form as graphite and as diamonds. It is also the fuel element in coal. The symbol for Carbon is C. Calcium Carbide (Ca C2) is a compound of Calcium and Carbon in the proportions of 62 ])er cent calcium to 38 per cent carbon which combine to form a hard crystalline substance of a dark gray color, *Iii describing the manufacture of calcium car- bide it is well for the reader to remember that the materials employed are among the most refactory ones which we know. Lime is so infusible that it is frequently employed for the material of crucibles in which the highest melting metals arc fused, and *Froni hullt'tin of the ilepartiiuMit of .-lii'iiiistry. I'ciiiisylvauiii. State Oollefro. 22 OXY-ACETYLENK WELDING AND CUTTING for pencils in the calcium light, because it is capable of with- standing extremely high temperatures. Carbon is the material employed in the manufacture of arc lights, and other electric appliances for the same reason. Yet in the manufacture of car- bide these two most refractory substances are forced into com- bination with each other. It is the excessively high temperature attainable in the mod- ern electric furnace, five to seven thousand degrees Fahrenheit, which alone accomplishes the combination of these elements to form calcium carbide. The electric arc being formed in the furnace, a thoroughly incorporated mixture of coke and lime in the right proportion is introduced. The change which takes place is Ca O -f 3 C = Ca C2 -f CO which means thai tifty-six pounds of lime, and thirty-six of coke luake 64 pounds of carbide, and liberate twenty-eight of carbon monoxide, a gas which escapes or is burned at the mouth of the furnace. Thus, for each ])ound of carbide made, there is con- sumed a pound and a half of a mixture which is something like seven-twelfths lime with five-twelfths coke. Granted pure material, there is formed an ingot of very pure carbide, surrounded by a crust of less pure product because par- tially unconverted. In breaking up, packing and shipping the carbide, this poorer crust is rejected. At first impure materials were employed for the manufacture of carbide, but this resulted in an inferior grade, which in turn yielded an impure gas, so that at the present time it is everywhere recognized as essential, that only first class ma- terials should be used. It is customary to use lime that is 99 per cent pure, and coke of low ash. Both must contain as little sulphur and phosphorus as possible. Carbide decomposes with water in accordance with the fol- lowing chemical equation : Ca C2 -f- 2 H2 O = C2 H2 -f Ca (OH) 2 A pound of absolutely pure carbide will yield ^y'j feet of CHEMISTRY 23 acetylene, but absi)lnte purity is not a practical commercial possi- bility. In practice good carbide may be expected to produce never less than four cubic ft. and rarely more than five cubic ft. of acetylene gas per pound of carbide. The table on page 2^ gives the gas yield of various grades carWde. TABLE III. TIIK AY K RAGE YIELD OF GAS. From the Xnrious (Jrados of Carbido. Grade 3l-.x2 414 cubic feet Grade 2 x \i> ^ 4i/^ cubic feet Grade li4x % 41/^ cubic feet Grade %xl/]2 _ 4 cubic feet Grade Electrolite - 4 cubic feet Calcium Carbide is a safe substance to store or transport under proper conditions. It cannot explode, take fire, or other- wise do harm, miless exi)Osed to moisture. In that event the water in the moisture will slowly liberate acetylene which in the presence of flame, will ignite. ACETYLEXE. -Xcetylene is a colorless, tasteless gas, possessed of a peculiar penetrating odor. It is a compound of two atoms of carbon to two atoms of hydrogen, and is known by the formula C2 H2. Being composed of these two elements only, it belongs to a class of compounds known as hydro-carbons. All hydro-carbons are combustible and acetylene will explode when only 3>^ per cent is mixed with air. Its ignition point is lower than coal gas, being about 900 degrees F. against iioo degrees required to ignite coal gas. It burns in air with a brilliant but smoky flame, uniting with the oxygen of the air. in the following proportions. 2 Cj II2 -f 502 = 4 CO2 + 2 II2 O Acetylene is an endothcrmic compound. In its formation heat is absorbed, and there resides in the acetylene molecules the power of spontaneously decomposing and liberating this heat if subjected to temperatures or pressure beyond the capacity of its 24 oxy-acetylp:ne welding and cutting nnstaple nature to withstand. Acetylene is decomposed into its constituent elements at a critical temperature of approximatel)- 1400 (leQTees F., or at the critical pressure of two atmosphere? (29.4 pounds) at which pressure it becomes dangerous. .Acetylene, without the mixture of air or oxygen, at ordinary pressures, is not explosive in any sense, except as referred to ?.bove. When acetylene is used in the blow torch it combines with oxygen in equal volumes and liberates much heat. The tempera- ture of the oxy-acetylene flame, taken at the extremit}- of the white jet. is very nuich higher than that of any other flame. It is calculated to be 6300 degrees F. In all cases the white jet of the oxy-acetylene flame can melt lime, the melting point of which is estimated at 5432 degrees. CHAPTER HI. PHYSICS. P)icitii'atics. — Pneumatics is that branch of mechanics which treats of the properties of ^ases and air. It was supposed In- the ancients that air was inponderable. that it weighed nothino-, and it was not until the year 1650 that it was proven that air really had weight. .\ cubic foot' of air under ordinary conditions, weighs about eight onediundredths of a pound. Since air has weight it is evident that the enormous quantity of air that constitutes the atmosphere must exert con- siderable i)ressure on the earth. By experiment and calculation this pressure has been determined to be 14.7 jx.nnds ])er square inch. In the strictest sense of the word, air is not a gas. but is a mixture of gases and consists of about 23 parts oxvgen and yy parts nitrogen, by weight; or 21 parts oxygen and 79 parts nitro- gen, by volume. Its physical characteristics are the same as the gases, and in this respect it is classified among them. The most striking feature concerning gases is that, no matter how small the (piantity ma\ be they will always fill the vessels which contain them, and if the temperature of the confined gas remains the same, the pressure and volume will always vary the same way. The law which exjjresses this is called I'.oyle's Law, and is as follows: Boyle s Laxv. — The temperature remaining constant the volume of a given quantity of gas varies inversely as the pressure. The meaning of this is : I f the size of the containing vessel is dnuinished to /. or >^ of its former volume, the pressure of the gas will be increased to 2 or 3 times its original pressure. It also means that if the size of the contaiiung vessel is increased to 2 or 3 times its original volume, the pressure will dinunish to >4 or Yi of the former pressure. In these and the following statements the reader should not confuse the w^ords volume and quantity. The volume will corre- spond with the cubic capacity of the vessel, while the quantity will represent the amount of air or gas contained in the vessel under pressure. 26 OXY- ACETYLENE WELDTXG AND CUTTING Suppose a steel drum is such a size that it will measure ex- actly 3 cubic feet. If it is open to the air it is evident the drum will contain 3 cubic feet of air at atmospheric pressure. Then if twice as much air, or 6 feet is put into the drum, the pressure will be doubled to 29.4 pounds, and if one hundred times as much air or 300 feet is put into the drum the pressure will be raised 100 times and become 1470 pounds. Xow if half of this air, or 150 feet, is drawn out, the pressure will be reduced to one- half of 1470 pounds and become 735 pounds. As a necessary consequence of Boyle's law, it may be stated that, iJic quantify of gas in a given si:;e drum, varies directly as the pressure. Knowing the quantity of gas a drum will contain under cer- tain pressure, the quantity for any other pressure may be calcu- lated by the following sinn)lc formula in which A ^ the nominal rated pressure B = pressure of gas in drum C = capacity of drum under A pressure X = contents of drum in cubic feet of gas Ti CB _ Then — . — — X A Expressing this formula in words, we have the rule. Multiply the rated capacity of the drum by the pressure of gas in the dru)n and divide by the nominal rated pressure to Und the contents of the drum. Suppose an oxygen drum contains 200 feet of gas at 1800 pounds pressure, and after being used for sometime the pressure has diminished to 700 pounds. If we wished to learn the quan- tity of gas still remaining in the drum, the calculation would be as below. 200 X 700 77 1800 ^^loO^^^' In all that has been said before, it has been stated that the PHYSICS 27 temperature was constant ; the reason for this wih now be ex- plained. Suppose a definite quantity of air at 32 degrees F. be placed in a cylinder with a movable piston and that this piston is weighted to cause the air to be at a constant uniform pressure. If the temperature of the air within the cylinder be raised to 33 degrees F. it will be found that the piston has raised a cer- tain amount, consequently the volume has increased while the pressure remained the same. If more heat is applied and the temperature raised to 34 degrees F. it will be found the piston has raised again, and that every increase in temperature will cause a corresponding increase in volume. The law that expresses this change is called (iay-Lusac's Law. and is expressed as fol- lows : Gav Lnsac's Lazv. — // tlic pressure remains constant every increase of temperature of 1 dc'^ree F. produces, in a i^iven quantitx of i^as, an expansion of ^'.j of its volume at 32 degrees F. If the pressure remains constant it will be found that every decrease of i degree F. will cause a decrease of .'..; of the vol- ume at 32 degrees F. According to the modern and now generally accepted theory of heat, the atoms and molecules of all bodies are in an incessant state of vibration. The vibratory movement in gases is faster than in liquids, and in liquids it is faster than in solids. Any increase in heat increases the vibrations, and a decrease in heat decreases them. From calculation and experiment, it has been concluded that all vibration ceases at a temperature of 460 degrees below zero. This point is called absolute zero, and all tempera- tures reckoned from this point are called absolute temperatures. When the word temperatu.re alone is used the meaning is the same as ordinarily applied, but when absolute temperature is specified, 460 degrees F. must be added to the temperature. The absolute temperature corresponding to 32 degrees F. is 460 -f- 32 = 492 dgrees F. In calculating the effect of an increasing or decreasing tem- perature, upon the volume or pressure of gases, the temperature is reckoned from absolute /.ero. 28 OXY- ACETYLENE WELDING AND CUTTING Suppose a steel drum is charged with 200 cubic feet of gas at 1800 pounds pressure, and at a temperature of 68 degrees F. ; and subsequently the temperature is raised to too degrees F. The increase in pressure may be calculated by the following formula in which A = the nominal ratetl j)ressure of the drum at 68 degrees Fahrenheit. T = the absolute temi)erature of 68 degrees F. t = absolute temperature of gas in drums E = pressure of gas at t temperature t Then A = E PHYSICS 2S) FIG. 12. HIGH PRESSURE PUMP FOR GAS COMPRESSION. Three cylinder liydraulie iiuinp liavinji; eapacity to compress 12 cubic feet of {ras per minute from 1,.")()0 poiiii'ls to 2,200 pounds pressure per square inch. 30 OXY-ACETYLENE WELDING AND CUTTING Expressing this formula in ^vords we have the rule. Divide the absolute teiiiperature of the gas in the drums by the abso- lute temperature of 68 degrees F., and multiply the quotient by the nominal rated pressure of the drum, to find the pressure due to a change in temperature. This final ])ressnre is computed as shown. 4()0 + loo =^*^^ J Q(3 460 + 68 = S2^ 1.06 X 1800 = 1908 = final pressure Heat. — As to the exact nature of heat, scientists dift'or. but all modern thinkers and investigators agree that heat is a form of ejiergv. ft is not proj>osed here to enter into the different theories regarding heat, but this nmch of the generally accepted theory is given to make clear the ]:)rincii)les which are to follow. To avoid possible misunderstanding the attention of the read- er is first directed to the difference between the quantity and intensity of heat. This difference is easier explained by a series of illustrative statements. 'J'he same amount or quantity of heat may be delivered to . T. l^ The Calorie. — 77/r quantity of heat required to raise one kilogram of leafer one degree Centigrade is ealled a Calorie. One calorie is e(|ual to 3.96 B. T. U. Temperature. — The wM:)rd temperature expresses the sensible heat which a substance possesses, and is measured by comparison with some other substance havino- the same amount of sensible heat. For convenience and for scientific purposes, two scales oi comparison are employed. I'.oth scales are compared with the same substance at the same temperatures, the only dift'erence being in the graduations of the scales. These are called the h\ahrenheit and (Vutigrade scales. Thermometers. — The instrument on which these compara- tive scales are arranged to measure temperature is called a ther- mometer. The divisions of the scale are called degrees, the substance with which they are com])ared is water, and the tem- perature at which they are coni])are(l is the freezing i)oint and l)oiling i)oint. Fahrenheit. — ( )n the hahrenheit scale the freezing ])oint of water is marked ^J, and the boiling ])oiut _'IJ. and the interven- ing space divided into 180 ecpial parts called degrees. Thirty- two degrees are marked off on the lower end of the scale, and called z.ero. So in speaking of water we would say that it freezes at 32 degrees above zero, and boils at 212 degrees above zero. 32 OXY-AC'KTVLKXK WKLDIXG AND CUTTING As many rlej:2^rees arc marked above the hoilins^' ]>(»iin (»r loelow zero, as are desired. Ccnt'r^radc. — Tii ^radualinij a Centigrade scale, the freezing point is marked zero, the lioihng point too. and the intervening space is divided into loo c(|nal degrees. Tt will he observed that too degrees Centigrade covers the same range of tem])eratnre as i8o degrees Fahrenheit, therefore, one degree centigrade ecpials one and eight-tenths degrees Fah- heit. Tem])eratures designated by one scale may be converted to the other scale b\- fonnnlas. When 1'^ -- degrees Fahrenheit and C' = degrees Centigrade Then 1.8 C + 32 = F. ^' - 3-' Expansion. — The \-olnme of any suljstance is always changed when the tem]ieratnre is changed: nearly all of them expand when heated, and contract when cooled. This phenomenom causes the welder considerable trouble unless it is thoroughly understood, and it is well for him to give this subject much ihought and study, for his success depends to a great extent, on his ability to over- come the effects of expansion and contraction. The method of overcoming these effects will be treated fully under the sulyject of wielding. Suppose that a bar of iron is exactly 10 feet long at a tempera- ture of 50 degrees F.. if the temperature be raised to 60 degrees it will be found that it has lengthened a definite amount. If the temperature is then raised to 70 degrees it will be found to have lengthened exactly the same amount as before. This is true of all metals. Each metal will expand a certain definite amount with every degree increase in temperature, and when cooling they con- tract at precisely the same ratio ; but the dififerent metals do not expand with the same ratio as compared one with the other. rnvsics 33 The ratio of expansion of the different metals has l)een deter- mined and the amount of expansion of one inch in length for one degree tenijierature has heen tabulated into a table called coeffi- cients of expansion. These seem like small amounts, but when the tem])eratin-es arc higli the amount of expansion is an item to lie considered. TAHLI-: A'. COEFFICIENTS OF KXI'AXSION FOH VAKIOFS 81BSTA.\CK8. Cast Iron 00000617 Copper 00000955 Brass 00001.037 Silver 00()00(i90 Bar Iron 00000(i86 Steel (uiitenipered ) OOOOO.'OO Steel (teni])erroured in the moulds which give it the desired shape it is rapidly cooled so that nearly all the carbon it contains is in the combined form. It can be readily understood from the preceding ]xaragraph that if this combined carbon can be precipitated to graphite the casting- will be softer, and furthermore if the size of these flakes of graphite can be reduced the casting will be stronger because the smaller are the planes of easy rupture. Being softer and stronger it may be bent and is called malleable. Eliminating and changing the carbon in white cast iron to make it malleable is accomplished by prolonged heat treatment and the process, which is called annealing, is performed after the iron has been cast into moulds and cooled. Thev are then METAL8 AND THEIR PROPERTIES 37 cleaned and packed in iron boxes with some pulverized sub- stance containing- oxide of iron, such as iron ore. or mill scale, placed in an annealing- furnace and heated to a temperature of 1300 degrees, and at this temperature they are kept for many hours. While under this heat there occurs the precipitation of graphite, which normally would have occurred during' solidifi- cation, and in the majority of cases nearly all of the combined carbon is changed to graphite, or eliminated by uniting' with the oxygen in the material used for packing. Under this treatment the graphite does not form in flakes ;is in ordinary cast iron, but forms in minute particles which are not nearly so weakening- or embrittling' to the casting as flakes of graphite would be. The whole annealing jirocess requires about six days of continuous firing, and should not be attempted by persons who are not faiuiliar with the chemistry of iron, or who do not possess an equipment <>f furnace, iron jiacking boxes and packing. Since mallealMe iron is always cast in the form of hard white iron and subsequently made malleable by a process applied to its exterior, it follows that the change of structure is more com- plete at the surface giving the outside the texture of mild steel, while the middle ])ortion may resemble a very soft cast iron. It is this peculiarity which frustrates the etYorts of the amateur Avelder. Wrou^^ht Iron. — Wrought iron is almost the same as very low carl)on steel, its chief distinction being in the method of refining rather than the composition of the metal. It is niade by melting pig iron, steel sera]) and other ferrous materials in contact with iron ore. and burning out the impurities, leaving metallic iron. This iron is not in a melted state when finished, for the temperature of the furnace is not sufliciently high to keep it fluid after the carbon has been burned. It is in a pasty condition and when taken out of the furnace is a honey-comb of iron with each cell filled with melted lava. This honey-cc^mb is then squeezed and rolled until most of the slag is worked out and the iron frame work welded together in a crude rough bar. These bars, which are an intermediate i)roduct. called "'muck 38 OXY-ACETYLENE WELDING AND CUTTING bars", are then cut into lengths, "piled", heated to a welding heat and rolled again, and after this second rolling they become the "merchant iron" of commerce. The finished bar contains less than .12 per cent carbon and about 1.5 per cent slag. Some think that this slag serves as a flux and assists in welding, but this is doubtful. It is more probable that the easy welding of wrought iron is due alone to its being low in carbon. Steel. — In olden times all kinds of steel, whether made in the crucible, in the cementation chamber or in the puddle furnace, contained carbon enough to make them suitable for cutting tools when hardened in water, and the steels that were later made in the Bessemer converter during the early days of its history were all more or less hard, much of it being used for tools ; conse- (luenth' the metal made in the converter was called Bessemer steel. As time went on and the cost of operation was reduced below that of making wrought iron, a great deal of very soft metal was made in the converter and open-hearth furnace. It was impossible to draw the line between this steel and the earliest products of the converter, so practical men in America and Europe did not try to do so, but called everything that was made in the converter, or in the open-hearth, or in the crucible by the name of steel, although the product may at times resemble wrought iron, and it is a fact that the method by which steel is made cannot be discovered by ordinary chemical analysis. The primitive Tubal Cain could produce a hard cutting instru ment w'ith no apparatus save a wrought iron bar and a pile of charcoal; and the natural developments have led to the conclu- sion that a given content of carbon will confer a greater hard- ness and strength, with less accompanying brittleness than any other element. There is such a widel\- varying quantity of carbon and other alloys in steel, accompanied by as wide a range of physical properties, that the subject cannot be treated in a book of this kind; but before leaving the subject it is well to speak of a proc- M1-:TALS AM) TIlKlIf I'KOI'KHTIKS 39 ess by which hard tool steel may he made, which has not here- tofore been mentioned. This is known as the ''cementation" or "blister" process and is undoubtedly the one used by Tubal Cain as mentioned in the ])recedino" paragraph. Bhster steel is made by placinj^' bars of \cry jnire iron in Ion*;- pots with char- coal and exposing- them to al)Out 1300 degrees heat. This heat is maintained for abcnit ten days and when the bars are removed thev are graded according to their carbon content which ranges from .5 to 1.5 i)er cent, .\lthough this process is ex])cnsive. it produces a ver_\- tine grade steel and it is still being used in Sheffield, England. This ])rocess is mentioned here to remind the welder, that un- less he uses a ])erfectl}- neutral flame, it is ]:)ossible to carbonize his weld, and form a scale that cannot be machined. In other words, if he uses more acet\lene gas than his oxygen can consume, the carbon of the unburned acetylene ma}- unite with the iron by a process somewhat similar to the blister process. Like other metals steel expands and contracts with heat or cold, and the amount of this expansion is about one sixty-fourth of an inch for every 250 degrees change of temperature. TABLK VI. MELTIXG TE.MKKATUKK OF .MKTALS. Name of Metal Temperature Name of Metal Temperature C F C F Tin 223 327 419 449 621 7Sfi White Cast Iron Gray Cast Iron... Jfaril Steel 1100 2012 1200 2192 1400 2552 1471 2680 1484 2703 1500 2730 1776 3232 2000 3632 1 Lead Zinc Aluniiuiun 657 T^12 Mild Steel Bronze .._ Brass 900 950 961 1652 1742 1762 1949 1949 Nickel Wrought Iron ... Platinum Silver Copper Gold 1065 1065 Iridium Copper. Copper is the only metal which occurs free in large, widely distributed clejiosits. For this reason, it was the first metal exclusively used by man. The copper age followed the stone age. The island of Cyprus was noted in the time of the Romans 40 OXVArKTYLKXE WELDING AND CUTTING for its jjfi idiictioii of copper, or as it was then called, Cyprian brass. \\'e obtain the symbol C_"n. from the Latin name, Cnprum. The noted mines of native copper in Michigan, along' the south shore of Lake Superior, were extensively worked before Columbus discovered America. From them masses of copper of enormous size, one of which weighed nearly five hundred tons, have been obtained. These mines are still an important source of co])per. Copper has a characteristic reddish color. ( hily two of the connnon metals, g'old and silver, surpass it in malleabilitv and ductility, and it stands next to silver in as a conductor of elec- tricity and heat. The tensile strength, which is about ^^.ooo ll)>. ])er scjuare inch at ordinary temperatures, decreases rai)idl\ under the effect of heat. At 932 degrees it is only about i4(X)o lbs. per square inch. When cop])er is melted it oxidizes rapidly in contact with air, and this oxide is very soluble in the metal; it forms with it an alloy, which crystallizes with the mass on cooling. Melted copper also absorbs hydrogen and carbon monoxide which are present in the oxy-acetylene flame, and on cooling, the metal is riddled with blow holes. The effect of this oxidation and absorb- tion of gases, can only be overcome by the use of fluxes and alloys in the welding rod. Brass. Brasses are alloys of copper and zinc. They do not conduct heat so readily as copper, but their tensile strength when hot is much higher than copper. The reader will note the great dif- ference in melting points in the two principal elements in brass. Zinc melts at 786 degrees F. and vaporizes at 1684 degrees, while the melting point of copper is 1949 degrees, or 265 degrees higher than the vaporization temperature of zinc. When brass is melted under the direct action of the tlame, this vaporization of zinc is very pronounced. The copper in brass also retains its property of absorbtion and oxidation. So we say that the MKTAi^ AM) THKIK I'ROPKHTI KS 41 melting- of brass under the action of the torch is attended In three distinct phenomena: Absorbtion of gases; volatihzation of zinc ; and oxidation. These difficidties are overcome by use of the proper weUUng rods. Alloys. *Accor the same relation to the melted solution as a pure solid metal does to the same metal when melted. C"onse(|uently any solution of these metals will cool to the freezing point, without there being any iiuj)or- tant change in their rclatit)n. The reason that these solid solutions form in any proportion is that the two metals crystallize alike. It is, perhaps, a new thought to the reader, but it is true, that a metal forms a crystal when it solidifies. Furthermore, each metal has a particular, general shape which its crystals assume, and there is no force powerful enough to prevent theiu from taking this shape in preference to any other. Tiny as the crystals sometimes are, often re([uiring the highest powers of the microscope to reveal them, dieir crystalline forces are verv powerful. If. therefore, two metals do not form like crystals, thev cannot solidify in st)lution, i. e., in the same crystal, *Froin Metallurjiv of Iron mihI Steel, hv Bradley Stou<:htoii. 42 OXY-ACETYLEXE WELUIXG AXD CUTTIXG but crystallization (i. e., freezing) must be accomplisbed by precipitation, or separation into two distinct substances." Tbere are a great uuniber of alloys all having" different phys- ical projierties, and this diiterence is sometimes due to the presence of an element in very small proportions. When melted the components of an alloy sometimes react with the flame in entirely different ways, and unless welding rods and flu.xes are used, which will compensate for this reaction, the entire struc- ture of the alloy may become changed. The welder should therefore carefully adhere to the instructions given on welding the various alloys. On the following page is given a list of alloys, their compo- sition and proportions. Sb. ^=- Antimony, Bi = Bismuth, Cu. = Copper, An. = Gold, Fe. = Iron, Pb. = Lead, Ni. ^Xickle, Ag. = Silver, Su. = Tin, Zn. = Zinc. TABLE OF AELOVy. Name of Alloy. Proportion l)y weight. Brass, common yellow '1 Cu, 1 Zn Brass, to be rolled \V1 Cu, 10 Zn, 1.5 Su Brass castings, common 20 Cu, 1.25 Zn, 2.5 Su Brass castings, hard 25 Cu, 2 Zn, 4.5 Su Brass, propellers 8 Cu, .5 Zn, 1 Su Gun metal 8 Cu, 1 Su Copper Hanges 9 Cu, 1 Zn, .26 Su Statuary 91.4 Cu, 5.53 Zn, 1.7 Su, 1.37 Pb German Silver _ 2 Cu, 7.9 X^i, 6.3 Zn, 6.5 Fe Britannia 50 Sb, 25 Su, 25 Bi Chinese Silver 65.1 Cu, 19.3 Zn, 13 Xi, 2.58 Ag, 12 Fe Chinese white copper 20.2 Cu, 12.7 Zn, 1.3 Su, 15.8 Ni Medals 100 Cu, 8 Zn Babbitt's metal 25 Su, 2 Sh, .5 Cu Bell metal, large „ 3 Cu, 1 Su Bell metal, small 4 Cu, 1 Su Chinese Gongs „ 40.5 Cu, 9.2 Su Telescope mirrors 33.3 Cu, 16.7 Su White metal, ordinary 3.7 Cu, 3.7 Zn, 14.2 Su, 28.4 Sb White metal, hard 35 Cu, 13 Zn, 2.2 Su Metal, expands in cooling 75 Pb, 16.7 Sb, 8.3 Bi METALS AND THEIR rKOPERTIES i'S- Aluminum. Althouiih aluminum is one of the most abundant and widely distributed metals, it never occurs free in nature. Our common clay consists chiefly of aluminum silicate and it has been esti- mated, there is enoug:h aluminum in every brick to form a coat- ino; an eighth of an inch thick, over its surface. Therefore it is not the scarcity of aluminum that contril)utes to its cost ; but the expense of extracting- it from the silicate. The only process used at present for the extraction of alum- inum is an electrolytic one. The apparatus consists of a rec- tangular ircMi box. lined with a thick layer of carbon which con- stitutes the cathode. The inside dimensions are about 4J/2 feet long', 2/2 feet wide, and 6 inches deep. Carbon rods about 3 inches in diameter and 18 inches long-, placed in rows and sup- ported b}- copper bars, serve as the anodes. The process is made continuous by adding raw material at the top and draw- ing ofl: the aluminum at the bottom. The product is 99 to 99^^ per cent pure, and the remaining y, per cent impurities con- sists of traces of iron, silicon and sodium. Aluminum melts at 1212 degrees F., and when in the molten state it oxidizes rapidly and al)sorbs gases. The strong atifinity of aluminum for oxygen is made use of in the product called Thermite. Thcnnifc. — When a mixture of very tine particles of alum- inum and iron oxide (iron rust) is ignited a rapid combustion and very high temperature ensues. In this reaction the oxygen, in the iron oxide, unites with the aluminum, setting the iron free and liberating 4400 degrees heat. This mixture of aluminum and iron oxide is known by the trade name of Thermite, and the reaction of this substance is used to furnish heat and material for thermite zceldins- 44 OXV-ACETYLENK WELDING AND CUTTING CHAPTER \'. ACETYLEXK ( iEXER ATORS. The function of an acetylene j^enerator, is in principle, a simple one. It has to bring' together the water and carbide, wash the gas and store it in such quantities as may be neces- sary. There are two general luethods of bringing the water and carbide together, viz.. "carbide tn water" and "water to carbide." Generators are therefore more fre(|uently designated as carbide-feed, and water feed. res])ectivel\ . Inasmuch as it is easier to regulate the tlow of water. 1)\- means of valves and other methods in common use. than to control the distribution of carbide, it was natural that the earlier generators should ojierate by s])rinkling, or dripping water onto the carbide. Eater, it was observed that the more rational plan was to drop suit- able (juantities of carbide into a large e.xcess of water. l'"rom these principles originated the various types of generators which are on the mark'et today. Recall the heating ])henomena of reaction. Water consists of hydrogen and oxygen, the dissociation of which absorbs heat. On the other hand, the o.xygen liberated combines with the cal- cium carbide, and the reaction liberates much more heat than is absorbed b\' the former reaction. This excess of heat is about <)00 B. T. I', per i)Ound of carbide; which is sufficient to raise the temperature of one gallon of water through 90 degrees F. No device or arrangement can alter the amount of heat lilierated, and if no cooling is effected, and the carbide is in excess pro- portion to the water, the temperature may become very high. Hig^h temperatures luay be caused when large (piantities of car- bide are heaped in a ciuantity of water. In the exterior of this heap the water reacts with the carbide rapidly and the heat liberated prevents it reaching the interior of the mass, except in very small (juantities. Arottnd the outside the carbide is decomposed to lime, and lime being a poor conductor, prevents the radiation of the heat liberated at the interior. Under these conditions the mixture may become red hot. Although, as has been said before, no arrangement can alter the amount of heat liberated, the temperature may be regulated ACET^T.KNK GEXKKATOES -^-^ by haviiio- an excess of water to absorb the heat. Re.c:ardless of this there are i^enerators manufactured which do not utihze this or any other cooHnq- agency. Z)/7> Type Generator.— In this type of generator, small quan- tities of water are dropped onto a large mass of carbide. The amount of water being regulated by the pressure or quantity of the accumulated gas. On account of their simplicity they are freciuently used for small portable generators, and when started they should be allowed to work continuouslx until the supply of carbide is exhausted. These generators give the greatest amount of heating and the most impure gas. Floodiiii^ 'J'ype c;eiierators.—h\ this generator the carbide is placed in i)ans. having dividing walls to separate them into compartments containing about two pounds each. The water control is arranged to first enter compartment Xo. i, exhausts and completely floods it. and then ilows into the next compart- ment where it finds a fresh supply of carbide. This overflowing from one compartment to the other, continues until the contents of the generator are exhausted. These generators possess the same disadvantages as the drip type: but not to so marked a degree. Carbide to ll'ater Type.— These generators are provided with a hopper of some sort, which contains the carbide, and are pro- vided with a mechanism for automatically dropping it into the water below, at the right time and measured quantities to mam- tain a constantly uniform pressure. These feeding mechanisms are of two kinds, one consists of some kind of a valve or shutter which opens at the right moment and drops the carbide directly into the water, the other depends on feeding the carbide over the edge of the plate. Kither of these arrangements must be safeguarded so that it is impossible to accidently drop the entire quantitv of carbide into the water. The feeding mechanism must be positive, strong and simple, for on it depends the perfect, uninterrupted and economical operation of the machine. It must ])ositively feed carbide when^ it is needed, and with e(|ual reliability prevent the feeding of 46 OXV-ACKTVl.KXK UELDiXG AND CUTTTX(. FIG. 2 4. TYPICAL CARBIDP: TO WATlJK GEXE RATOK. AC ET ^■ lA'] X H ( ; 1". N !•: i; ATORS 47 carbide ^vhen it is not needed. The water chamber should hold cnouiih water to absorb the heat liberated by the decomposing carbide, without excessive temperature, and the carbide should be fed in very small quantities (piece by piece) with diminishing or increasing- frequency as the demand for gas decreases or increases. When standing in the shop, acetylene generators are subject to accidents and nn'sna])s. just the same as any other piece of e(|ni|)ment ; the tang of a hie may be thrown through the shell . of the generator and allow the gas to escape. To avoid trouble in instances of this nature, the modern generators i)rovide that carbide will not feed into the water in C()nse<|uence of lowered pressure due to accidents to the generator. This is accomplished bv utilizing tlie How of gas. to the service pipe, to operate the carbifle \vc(\. "Carl)idc to water" generators as just (lescril)ed, generate the most i)ure, cool, gas at a constantly uniform pressure. They are more economical, safer, and otherwise more satisfactory than either the Drip Type or Flooding Type generators. There are two different designs in this type of generator. One having a gasometer in which a quantity of gas is stored ready for instant use ; and the other in which no gasometer is required, the gas being generated on demand. (Generators with- out gasometers have the advantage of having less gas in storage in case of injury from accidental causes ; they are less liable to give trouble 1)\- freezing, they are not so cuml)ersome to handle and conse(|uently better adai)ted to portable use. Sclrcfiiii:; a (Generator. — As to the selection of a generator, there are good generators in both of the last named types, and it is an easy matter to select the one best suited to your require- ments. C)i whatever type it may be, a good generator should possess the following qualities: (i) It must insure cool generation. Since all machines are slightly lieated during rapid generation, a pound of carbide decomposed in water always liberates the same amount of heat Nine hundred 1'.. T. U's. are liberated from every pound ot 48 0XY-AC?:TYLKNI'] WKLDIXG AM) crTTING decomposed carljide. and tliis heat should lie absorbed in a suf- ficient quantit}- of water to insure that no part will become heated enough to become dangerous. (2) There should always maintain a constant uniform pressure, sufficient to insm-e a rapid flow of gas to the torch; but never more than 2() pounds. A pressure of 29 pounds at any point may become a source of danger and more than 15 jiounds is uimeccssary. (3) It shoidd be well constructed, built of good material selected to resist the chemical action of the gases and carbide, of sufficient weight and proptirtion to withstand the stress of care- less handling. It should be built for service, and not merely to sell. (4) It must be simjile. A'oid of numerous or complicated mechanisms, easy to clean and recharge, and reliably automatic in operation. (5) It should generate the maximum amount of clean washed gas. (6) It must be so designed, that if any part fails to work, becomes broken or dislodged, it will result in stopping the carbide feed. (7) The feed regulator should be actuated by the combined influences of lowering pressure and flow of gas to the service pipe; and should not be actuated bv either one of these in- fluences alone. (8) It should be e(|ui]ii)ed with ])ressure gauge, safety valve, and an interlocking arrangement of the valve handles that will preclude the possibility of careless mani])ulation. In other words it should be "fool proof." Generators of the carbide to water ty])e are undoubtedly the best. With the water in excess, it is im]x)ssible for the tem- perature to rise to the boiling point of water, and under all con- ditions this class of generator yields the purest gas. As the acetylene bubbles up through the water it is washed free from A (• i: T \' 1 , !•; \ K ( i I-: \ i-: i^ a tors 49 most of its impurities. They are perfectly safe to move on trucks while charsjed, and under pressure and it is impossible for them to explc^le if they are desiQued and constructed on the lines prescribed. MODKRN AC'Kl-VLI<:.\E (iHNERATOR 50 CHAPTER VI. OXY-ACETYLENE TORCHES. ^v/ 'K/ r!** <> '. it w FIG. 1.".. ^roDKK^■ oxv-acetylkxk wiildixg torch T(i the casual observer, the oxy-acetylene torch is comparative- ly a simple construction consisting of a body or handle at one end and a mixing head at the other end, e(|uipped with tips or nozzles of various sizes to direct the flame against the work; but the requirements of this torch are very exacting. The velocity of propagation of the oxy-acetylene flame is about 330 feet per second, and to prevent the flame flashing back into the torch head, it is necessary that the velocity of the gases, as they leave the torch, should equal or exceed this velocity This "■flashing back" is a condition in which the flame enters the end of the torch and follows back into the mixing chamber. This feature in a torch is very annoying and causes much delay, for it necessitates turning ofT the gases, relighting the torch, and adjusting the flame, before proceeding. While this is being done the work is cooling, thus the delay and incon- venience amounts to more than merely relighting and adjusting the torch. Acetylene when burned in the air requires about Ave times its volume of oxygen to completely consume it. This is also true when burning acetylene with the oxy-acetylene torch ; but to obtain the best results, it is necessary to only supply one volume of oxygen to one volume of acetylene, the other four volumes of oxygen being supplied by the air. If more or less than one volume of oxygen is delivered by the torch, it results in waste of oxygen, or lowering temperature. ACETYLENE TORCHES 51 The intense heat obtainable with this torch is dependent on the rapidity of combnstion and this, in tnrn, depends on the thorough niinghng- of the gases, so that each atom of oxygen is in close association with a molecule of acetylene, ready for instant combination. To obtain this thorough mixture of equal (|uantities of gas and eject them at the required velocity, is more difficult to ac- complish than might be supposed. The factors that contribute to this (lifficult\- are. the difference in specific gravity of the gases, the different pressures at which they are supplied, and the varying quantities required by the different tips. Another feature to be obtained in a good torch, is that it should handle well, or be well balanced to facilitate easy and rapid manipulation. When the torch is being used for welding it is in constant motion, describing little circles of uniform size overlapping each other and equally spaced along the line of the weld. The motion is somewhat similar to that of the penman writing a series of overlapping loops in a continuous uninterrupted line. The reader has perhaps practiced this exercise in penman- ship, and knows the importance in having a pen that handles right. A well balanced torch is of ef|ual necessity to the welder. The foregoing re(|uirements are general and apply to torches of either the high or low pressure types. According to the pressure of the acetylene supply, oxy-acety- lene torches are of two types, the low pressure torch, which is designed to use acetylene at a tension of only a few ounces, and the high pressure torch designed to receive acetylene at a pres- sure ranging from 2 to 12 pounds. Low Pressure Torches: — -To obtain the desired velocity at the tip of the torch, the oxygen must be delivered at high pressure, and to provide equal volumes of gases, at such a difference in pressure, it is necessary to utilize the velocity of the oxygen to promote the fiow of acetylene. This is accom- lished by a device similar to the injector, or aspirator. The oxy- gen nozzle opens into the center of a conical chamber, where it draw's in the acetylene, mixes, and is then ejected through an ex- 52 OXY-ACETYLEXE WELDING AND CUTTING pansion chamber where the velocity is reduced to a suitable value. The oxyg'en being supplied at a pressure so greatly in excess to that of the acetylene, it is thought possible for it to blow back through the acetylene tubes, and produce in them a com- bustible mixture, in fact the first inventors of low pressure torches greatly feared the "ilashing back" of the flame into the acetylene pipes, and to prevent this they devised many ingenious arrangements, which are still indispensable. High Pressure Torches : — The design of high pressure torch is, in a general wa}-, on the same lines of the low pressure torch. That is the injector principle is used ; but not to so great an extent. The acetylene and oxygen being used at nearly the same pres- sure, there is no tendency for the oxygen to blow back into the acetylene tube. A more perfect mixture of gases is obtained, be- cause the oxygen does not tend to force a passage way through the acetylene ; but remains in association with it long enough to become thoroughly mingled. This resuhs in greater economy. The high pressure torch is more universal in application, be- cause flames of different magnitude arc obtainable by regulating the valves which control the gas supply, while with the low pressure it is necessary to change the nozzles and mixing cham- bers, in consequence of these advantages there is a growing favor for high pressure torches. To facilitate welding in inaccessible ])laces and permit their use in welding machines, high pressure torches are constructed in a variety of lengths and shapes, a few of which are illustrated. Fig. 15 shows a torch designed for general hand use. It is provid- ed with "tips*' or nozzles of different sizes, and by inserting one or the other, as the occasion may require, the widest range of work may be handled, varying from the thinnest sheet iron to the heaviest steel casting. Table XI, in the back of this volume, gives the size of tip best suited to the weight of the metal be- ing welded, and shows the amount of gases each tip will con- sume per hour. When large castings have been preheated to considerable extent, the heat which they radiate to the atmosphere, makes it verv uncomfortable for the welder to stand over them and use ACETYLENE TORCHES 53 /////// FIG. Hi. OXY-ACETYLENE TORCH. This torch is made longer than the standard, to t'ai-ilitate welding in places the operator cannot aj)proa(-h on account of inacessihilitv or radiating heat. the torch. In these instances it is sometimes more convenient to use a torch of unusual length, so that the welder may stand at a more comfortable distance. These lor.o- torches are fre- (}uently used to reach a weld that is impossible for the welder to approach on account of it being- inaccessible. These torches may be made any length to suit the welder or the occasion : but experience has demonstrated that when the length exceeds 36" the torch becomes difficult to handle. On this account, torches for this purpose are usually made about 34" long. All of the standard torches are constructed to direct the tiame down at a right angle to the handle, or at an angle varying lightly from this position. This arrangement luakes it impossible to do welding in the bottom of a tank which is too small for the welder to enter, and to facilitate work of this kind, the manufacturers have provided, what might be called a Straight Line Torch. In this torch the head and mixing chamber are arranged to deliver the flame straight away from the operator, or in a line with the handle. Cutting Torches -.Steel plates 1-8 or 3-16 inches thick may be readdy cut by the oxy-acetylene process without any special changes in the torches just described; but for greater thick- nesses a special torch is required. FIG. 17. STRAIGHT LINE TORCH. 54 OXY-ACETYLENE WELDING AND CUTTING A complete description of the oxy-acetylene cutting process is described in chapter XII. The principle upon which the cutting- torch is constructed is to provide a flame to raise the temperature of the metal to red- ness and then deliver a jet of pure oxygen against the heated surface. Some of the earlier torches resembled the regular welding torch with the addition of an auxiliary oxygen tube. This tube received its supply of oxygen from a point in the handle beyond the control of the needle valves which regulate the flame; and delivered its oxygen close beside the base of the flame. FIG. 18. OXY-ACETYLENE CUTTING TORCH. It is ])rovided with a valve to regulate the flow of oxygen, independent of the supply required by the preheating flame. There are several features, of this type of torch, that are well to consider. The greatest economy and speed are obtained with the purest oxygen. In fact there is considerable eft'ort expended in generating and maintaining pure oxygen for this purpose; but in torches of this type, if the oxygen is polluted with air just at the moment it is to be used, the results are not as satis- factory as they might have been, if the jet of oxygen had been protected from the atmosphere. Since the preheating flame must precede the oxygen jet in the line of the cut, it follows that these torches can only be ad- vanced in (^ne direction, that is, with the oxygen jet following ACETYLENE TORCHES 55 the flame. Then, to cut a hole through a plate, the operator would have to take different positions around the plate. In other words he would either have to walk around his work or assume some exceedingly awkward positions to keep the oxygen jet continuallv in the rear of the preheating flame. Manufacturers of modern torches have overcome these dif- ficulties by placing the oxygen jet inside of the heating flame, where it is protected from the surrounding air, and is ever in a position to do its work, irrespective of the direction the torch is being moved. When the occasions for using the cutting torch are frequent and interrupted, it is desirable to possess a torch designed ex- clusively for this purpose; but if the events of its use are only incidental, an attachment ma\- be ajjplied to the welding torch, which will admirably serve the purpose of the cutting torch, and give as perfect satisfaction. One or these attachments is illustrated in Fig. 19 which shows the \ ulcan Combination Cutting and Welding Torch. This combination consists of an auxiliary oxygen tube and cutting head, which, when attached to the Vidcan welding torch, makes a perfect cutting torch of the nnxlern type ; the ])reheatiug t1ame is formed in a hollow annular cone, with the oxygen cutting jet in its center, as described in a previous paragraph. X/' FIG. 19. VULCAN COMBINATION CFTTIXC, AND WELDING TORCH. 56 OXYACETYLEXK WKLDIXG AND CTTTING Instructions on Assonblin;^. Wilcaii combination and weld- ing- torches are furnished assembled and ready to use, but when a customer has previously ])urchased a welding t()rch, and at a later period orders a cutting- attachment, he may require some instructions on how to asseml)le the coml)ination. .Assembling these parts is only the work of a very few moments, and if the same routine is followed each time, the performance becomes habitual, and the combination is made very C[uickly, without distracting the operator's attention from other w^ork. An outline of procedure is recommended as follows, the parts and letters referred to are indicated in big. 19. To (|uicklv assemble this combination, imscrew the miion nut (." and remove the cutting head from the tube. Then attach cutting head to the head of the torch by screw- ing A into R up to the shoulder on A. and tighten by hand. Tf the cutting head does not align with the torch it should be made to do so, by loosening the nut D and swinging it to the position shown in the illustration. When this position h.as been obtained the mit D must l)e screwed down tight onto the cutting head. The small machine screw 11 should then be removed from the clamp G and the clamp slipped over the handle on the torch at I. Attach E to F and attach the tube to the cutting head by re- turning the union nut C to its original position .shown in the il- lustration. Then replace and tighten the machine screw H. See that the thumb lever O is up in the released position, which closes the oxygen valve J, and close the needle valves L and M. The torch is now ready to be connected with the hose. At- tach the red acetylene hose to the lower connection and the black oxygen hose to the recently applied upper connection. The oxygen and acetylene gases are ignited at R and the tips N are not used in cutting. ACETYLENE TORCHES 57 To remove the cutting attachment, disconnect the oxygen hose, remove machine screw H. disconnect E and, C and remove the oxygen tube by slipping clamp G from the handle of the torch ; then unscrew A from B, attach the black oxygen hose to the upper connection K, select a tip from N and insert it into B. The torch is then ready to use for welding. Figure iS shows the complete combination torch. FIG. 20. TOF{('H DKyiGNED FOK WKLDING MACIUNKS. 58 CHAPTER 7. PRESSURE REGULATORS. When oxygen or acetylene is obtained in drums at pressures ranging between 150 and 1,800 per square inch and used at the torch at pressures ranging from i to 54 pounds, it 1)ecomes neces- sary to employ some automatic mechanism that will make this reduction, and maintain a constant uniform pressure at the torch, irrespective of the original and constantly diminishing pressure in the drums. The device used to perform this work^ is known among weld- ers as an automatic regulator and accomplishes this regulated pressure reduction by automatically throttling the gas supply so that the pressure will remain uniform at the torch. As the gas enters the regulator it passes through a valve into an expansion chamber, one side of which is a flexible diaphragm. If the quant- ity of gas entering \h\> expansion chanilKT exceeds the quantity going out to the torch, there will be a natural tendency to in- crease the pressure, but this increasing pressure, deflects the dia- phragm and partially closes the valve ; thus the gas is admitted or throttled to suit the increasing or diiuiiiishing demand at the torch. Fig. 21 AITOMATUJ ACETYLENE REGULATOR PRESSURE REGUEATOKS 5c^ These regulators are provided with a spring and adjusting screw arranged to hear (hrectly on the (Ha])hragin. so that the final pressure may he adjusted to suit the requirements of the work. AUTOMATIC ().\V(n-:\ REGULATOR They are usually provided with one or two gauges to indicate the pressures in the drum and at the torch. A low pressure regulator equipped with one indicator is shown in Figure 21. The indicator dial shows the pressure of gas going to the torch, and the T handle on the front is used to adjust this pressure as the requirements demand. This type regulator is usually used on acetylene generators, hecause in this service it is only required to know the pressure of the gas going to the torch, the pressure in the generator hemg indicated hy an independent gauge. 60 OX Y- ACETYLENE WHLDING AND CUTTING A high pressure regulator with two indicators is shown in Figure 22. One indicator shows the pressure in the drum, and the other the pressure of the gas going to the torch. When used on oxygen drums the high pressure incHcator is useful in deter- mining the amount of gas in the drum as explained on page 26. it is therefore, sometimes called an Oxygen Regulator. OXY ACETYLENE WELDLXG I'LANT Showing application of automatic j)ressure regulators ACETVLKN K GKXKK ATOR CHAPTER 8. 61 Fiji. :!<• vri/'AX A^To^rATI(' acktvt.ene gknkhatok Chapter five outlines the various types of generators that can be used to prockice acetylene gas. In reading over the advantages and disadvantages of the different methods of generating ace- tylene, it will be noted that the "carbide to water feed" genera- tor has none of the disadvantages of the other types, but does have a great many advantages that arc not possessed by the others. Of the two styles of generators, low and medium pressure, the latter is the better for welding, because the acetylene and oxygen, should be delivered to the mixing chamber of the weld- ing torch at as near the same pressure as can be secured. 62 OXY-ACETYLENE WELDING AND CUTTING Where both gases are thus combined under positive, even pressure their mixture is more complete — assuming that the mix- ing chamber of the torch is properly constructed. Unless this thorough mixing of the two gases takes place, the result will be incomplete combustion, hence waste of gas and loss in efficiency. With the low pressure or gasometer type of generators, the injector type of torch is principally used. By this is meant that oxygen under high pressure, in passing through the mixing cham- ber of the torch, sucks the acetylene through with it. In this way the two gases are not thoroughly mixed, and the result is a waste of gas and a poor weld. I'he feeding mechanism of most pressure generators, now on the market, are ()])erated by means of complicated clock-work with pulleys and weights, leath- er diaphragms, etc. These frequently get out of order at just the time when operator needs the gas the most and the resulting delays are expensive as well as annoying. The Vulcan automatic acetylene generator works on entirely new principles, and the features that contribute to its success are so simple, unique, and |)erform their duly so accurately that the generator is well worth consideration. Its design is such that the demand for gas or the flow of gas to the service pipe, working in conjunction with the amount of pressure in the generator, automatically regulates the gas genera- tion to meet the varying demand at a uniform pressure. The rate at which the carbide is fed into the water varies directly with the rate at which the gas is used, and no more carbide is fed than is absolutely necessary to maintain the pressure at that particular moment. If gas is being used and pressure up to normal, or vice-versa if the gas is not being used but the pres- sure below normal, the carbide feed is inactive; but under these conditions a very slight dro]) in pressure, or the renewed de- mand for gas will cause the right amount of generation to take care of the moment's demand. The carbide feed automatically drops small quantities oi i% yi}i carbide, deep into a liberal quantity of water, and as the gas bubbles rise to the surface, they are cooled and washed, and emerge free from dust or other impurities P)y the arrangements set forth, many advantages are obtained. AC ET YI. KN E G EX E K ATO K ():> The most apparent of which is a very constant uniform pres- sure. After generation is eliminated on account of there being only a ver)- small quantity of carbide dropped at one time, and the gases are cool because there is not sufficient reaction taking place to perceptibly raise the temperature of the large volume of water. The i>4x^ carbide used in this machine generates one half a cubic foot more gas per pound, than the quarter or finely crushed carbide, and since all sizes (»f carbide are re- tailed at the same i)rice this feature alone effects a saving of I2>4 per cent in the cost of generation. The motor that operates the carbide feed is imposed between the generating chamber and the service pipe, and for the reason that it is not operated by the deminishing gas pressure only, but by the flow of gas to the service pipe combined with reducing pressure, the arrange- ment is an assurance that all the carbide will not be fed, or an excessive amount of gas generated, should the gas holder be accidentally punctured. The last mentioned, is a common fault of generators actuated by reduced gas pressure only. ^..^M Fig. ;!i VULCAN GENERATOR WELDING PLANT 64 OXY-ACETYLEXE WELDING AND CUTTING A word about the unique features of the motor will interest the reader. The runner or wheel from which power is received is entirely incased and not visible, but when removed it resembles an old-fashioned over-shot water-wheel. With the water-wheel power is derived from the weight of the water, in the buckets, descending" and rotating the wheel : but the wheel of the Vulcan motor is submerged in water and operated b}' the buoyancy of the gas gathering under the inverted concave buckets and rotating the wheel, in its ascent from the generating chamber to the service pipe. The arrangement is such that if the pressure is up to nor- mal, the gas is diverted through a by-pass, to the service pipe, without rotating the motor. In this description the reader will note the absence of springs, clock-work or weights which might make the apparatus cum- bersome. The generator is designed to deliver gas, at twelve pounds pressure, to oxy-acetylene welding and cutting torches. The pres- sure selected is deemed most suitable for the work. The suggestions and rules of the consulting engineers of the National Board of Fire Underwriters are strictly followed, in the manufacture and construction of Vulcan Acetylene Generators, and every precaution has been taken to insure safety and effi- ciency. The materials are the best, the proportions ani])lc, and the workmanship accurate, so that with proper handling the opera- tion will be eminently successful. To insure that these generators will be properly handled by even the most careless operators, each generator is equipped with a system of guards so inter- locked that it is impossible for an absent-minded operator to make mistakes. In fact there is only one way they can be manipulated, and that is the right way. Although it is impossible to pursue wrong methods in operating this plant we will outline the prop- er method. In this outline the parts referred to are indicated in Figure 32. Pipe Xo. I is the blow-off and should be extended, witliout traps and as few elbows as possible, to the outside of the building, and the end pointed down to exclude snow, birds, etc. Pipe Xo. 2 is the service pipe and, if the shop is piped, it should be con- nected to the supply line, but if it is intended to use gas directly ACHTVLi:\K GKXKRATOK 65 from the generator, thougli the hose, connect pipe Xo. 2 with. the acetylene regulator. Fill the chamber Xo. 3 and motor case Xo. 4 wiili water through liole Xo. 5 and allow to stand a few minutes for air hul)- hles to work out. •S^rfrv i/e^ r **^ ixti:kmok ok ntlcax oKXiiirvroij ]'>efore replacing the plug into Xo. 5 be sure the motor case is filled to oversowing. lo charge, or recharge the generator relieve the pressure by turning lever Xo. 6 one-(iuarter turn to the right, then agitate the sediment so ii will run (Uit. b\- n^atin^ the crank Xo. 7. Open the locking device by turning handle X'o. 8 one-quarter turn to 66 OXY-ACETYLKXK WIOLDING AND CUTTING the left. Draw ofif the sediment throug"h sludge cock by ttirning handle Xo. 9 one-quarter turn to the left. After draining, close sludge cock before proceeding further. Now swing lever No. 10 to a horizontal position and fill the lower part of the generator with water through funnel No. 1 1 until it overflows through No. 12; then return handle to Xo, 10 to its original vertical position. Remove cover No. 13, fill the carbide hopper with 1 '4x^carbide, rei)lace cover and tighten cap screws even and equally. Lock up the generator by swinging lever No. 8 to the right in its original position and closing lever No. 6 to the left over it. Put valve handle No. 14 in 1 vertical ])osition which closes the service cock. The generator is now ready for pressure which is started by rotating gear wheel X'o. 15 to the left until the pressure gauge indicates about three pounds. The carbide will then feed auto- matically and the pressure rise to the proper amount as soon as the service cock is opened and a little gas drawn oflF rh rough the torch. From this on the A'ulcan Generator is entirely automatic and needs no further attention until the contents are entirely ex- hausted. On account of these generators being self contained, com- pact in form, and complete without the necessity of a cumber- some gasometer, they are very suitable for portable purposes. One of these generators mounted on a truck, with oxygen drums and tool box. is shown in Figure 33. This makes a com- plete portable plant which may be taken to the work anywhere alxnit the shop or yards. / 'nlcau Generators are Safe because there is less surface sub- jected to injury than in many other types. There are no pipe connections between widely separated parts. They are less liable to freeze than generators having gasometers. Every movable part is safe guarded in a way that makes them fool proof. The carbide charge camiot be accidentally discharged into the water. It cannot be overfilled with water. ACETYLENE GENERATOR 67 Fiji. ;;;: VULCAN PORTAHLK (iKNKRATOR PLANT (58 OXY-ACETYLEXE WELDIXG AXD Ol'TTlXG CHAPTER 9. OPERATING PLANTS. This might be more correctly called operating;" a welding" shop, for it is the writer's intention to call attention to a few of the essential details, both in equipping and operating a shop. The subject covers such a range of information, that it would be im- possible to mention every detail, in fact it would not be practical to undertake such a task, for the equipment will be great or small, according to the amount and nature of the work which the operator expects to provide for. Whether the amount of work is considerable or not, there is one thing that should be uppermost in the mind of the operator, that is thoroughness and excellency of work. No matter how small or how large the job. the welding sliould l)c thoroughly, carefully and conscientiously performed. After a job has been finished it is often difficult to determine whether it is well done or not, this information may only be obtained by observing the welder while he is doing his work or testing the weld after it has been finished. Sometimes it is impractical to do either of these, and the integrity of the welder must be relied upon. Recognizing this truth, it is often the practice of boiler in- spectors, to condemn any welding on boilers which has not been done by welders of "known reputation," and since boiler work covers a large per cent of the field of his usefulness, the welder should make every effort to get into the class of welders of "known reputation." This also applies to other kinds of work. The occasions that require autogenous welding are frequentl}' of great importance. It may be a crank shaft or cylinder for some power plant, and if the welder does his work thoroughly, the job will hold and be as good as a new j^iece : l)ut it he is hasty or careless it will be very liable to fail, resulting in loss of time, money and possibly loss of life. For this reason persons who have work of this kind are wont to ])atronize welders of "known reputation." In work of the kind just described, the saving in time and money is sufficient to pay the welder handsomely for all the OI'KHATIXG PLANTS 69 time, care, or expense he may devote to thoroughly doing- his work and there is no excuse for slighting the job on the pretext that his customer will object to the expense. The only com- plaint that could justly be made, would be for time covered by idleness, for lack of foresight that may cause loss of time or de- lay, or charging for a service which you are not ecfuipped to render. Any equipment the welder can provide, will lessen the cost of the work and often facilitate better work. Therefore equip- ment sufficient for the work you expect to handle is an asset, which can hardly be dispensed with. Such conveniences as an assortment of handy tools arranged within easy reach, benches, brick welding tables, preheating furnaces, and facilities for hand- ling heavy work, contribute to good service and the pleasure of work, and are conveniences that may be built and installed during ones spare moments. Many welders have started their plant in a very modest way, buying their gases in drums and in every way curtailing the amount of the original investment. As their btisiness grew their mind was occupied in pursuing their trade, and the fact that their acetylene was costing them more than twice as much as it should, (lid not occur to them until they learned that a competi- tor charged one cent a foot for acetylene and made profit on it; whereas he could not make a profit on acetylene at 2 T-4C n foot. This leads to the explanation that acetylene in drums has an economic place in plants that have to be quickly transported to some remote location, over rough roads, in cold weather and also in shops where the occasions for using the apparatus are not very frequent. The cost of acteylenc in drums is 2c per foot at the recharging station and to this cost is added freight and cartage, while the cost of acetylene generated on the premises of the welding shop, seldom exceeds 7-8c per foot. In a shop where the welder uses the torch 6 hours a day, the saving ef- fected, by generating his own acetylene, will amount to $2.50 or $3.00 per day. In shops that are provided with an acetylene generator it is advisable to give it a permanent location in some corner where it will be out of the way and protected against freezing. 70 OX Y- ACETYLENE WELDING AND CUTTING The advantages of a permanent location for the generator are many. The time used in trucking it around the shops is eHm- inated, the blow off and shidge pipes can be extended to out- side the building, water may be piped to a place convenient to the generator, the generator will be less liable to become injured by collision, and the acetylene may be piped to any part of the building with drops and hose connections at different places most convenient to the work. Piping: — Acetylene generators are usually regulated to con- trol the gas pressure at about 12^2 pounds per square inch and since the largest tips consume gas at very nearly this pressure, it is essential that the gas should be conveyed through the pipes with as little loss of pressure as possible. It is recom- mended that the loss of pressure should not exceed 8 ounces. The factors to be considered in determining the loss in pres- sure are, the length and diameter of the pipe, the specific grav- ity and the initial and final pressures of the gas. The quantity of acetylene which will be delivered through pipes of different sizes with a loss in pressure of 8 ounces from an initial pres- sure of 11V2 pounds, may be calculated from the following formula, in which (D) represents the inside diameter of the pipe in inches and (L) its length in feet. 2809 \ 26 D' quanty of gas. TABLE IX. ACETYLENE DELIVERED BY PIPES OF VARIOUS SIZES AND LENGTHS, WITH LOSS OF 8oz. PRESSURE FROM AN INITIAL PRESSURE OF 113^ LBS. Xoniinal Size of Pipe Leugth of Pipe in feet 100 1 200 306 616 1,144 2,266 300 ^250^" 503 934 1,850 400 ~216 436 809 1,602 500- 600 700 1^ 434 872 1,618 3,204 193 390 723 1,433 177 356 660 1,308 163 329 611 1,211 % 1 114 OI'KKATIXU PLANTS 71 In using this table the pipe fitter should add to the actual length of the pipe, a sufficient length to compensate for the fittings, as obtained from table VIII. The effect of a bend or sharp angle in a pipe is to retard the flow of gas. This is least when the radius of the bend is five times the radius of the pipe. The most convenient way of stat- ing the resistance offered by bends, is in terms of equivalent length of straight pipe which offers the same resistance to the flow as the extra resistance due to the bend. A formula given for this equivalent length is L = 12.85 1 L=equivalent in feet r=radius of pipe R=radius of curve ]=:rlength of curve in feet measured on center line. The following table gives the additional length required to equal the friction due to globe valves. For standard elbows and trees, take ~/s the value given in the table. TABLE VIII. ADDITIONAL LENGTHS OF PIPE THAT WILL CAUSE FRICTION EQUAL TO THE FRICTION DUE TO GLOBE VALVES. Diameter of pipe Additional length in inches. in feet. 1 2 i>4 4 2 7 2>4 lO 3 13 4 20 5 28 6 36 72 OX Y- ACETYLENE WELDING AND (TTTING The blow-off or exhaust pipe should extend to the outside of the building with as few elbows as possible and terminate with the end pointing- down to exclude the snow and water. The sludge pipe or drain pipe as it is commonly called should not lead direct to a sewer, but should first discharge into an open pit. This pit may be provided with an overflow, about 3 feet above the bottom, which may then lead to a sewer. The pipes from the generator to the pit should have a fall of about one inch to twelve feet and from the pit to the sewer one inch to 20 feet. If a sludge pit is constructed that will drain and leave the residuum comparatively dry. this material may become of some pecuniary value. The chief uses of the sludge, frequentlv called acetylene lime, are for mixing mortar, for whitewashing fences, cattle pens, fruit trees, etc., for making paths, and for fertilizing, with some occasional application as an insecticide and disinfectant, mortar made from it is reported to bind quickly and hard ; there is no reason why mortar made from it should not be at least of equal value with mortar made from slaked lime. It may be added that any of the uses to which ordinary lime white wash is applied, a white wash made of carbide residuum answers equally as well. In view of the mauy particular uses U) which acetylene lime has been successfully applied, and particularly because of its usefulness as a fertilizer, it may not be out of place to submit the chemical analysis of carbide residuum. The following figures show the analysis of three specimens of residue taken at remote places. Sand (silica) Carbon (coke or coal) Oxide of iron and aluminum Lime Water and carbonic acid The services pipes, or mains that connect the generator with the torches must be securely fastened, without sags that may form pockets and when practical, they should drain toward the 1 -^ 3 r cent P< ?r cent I'er cent 1.24 1. 10 •97 2.08 3-95 2.14 311 2.9 2-3 62.5 63.65 66.1 31.04 28.4 28.47 OPHKATIXG PLANTS 73 g'enerator. It is advisable to use g;alvanized pipe because the acetylene is usually a little moist and forms oxide of iron, which comes off in a powder and may accumulate in certain parts. Pipes of red copper are strictly prohibited because the acetylene and copper can form acetylide of copper, which is spontaneously combustible. Tcsfiiii:; : As soon as the pipes are all in place and are prop- erly secured, the system should be tested, to find whether it is perfectly s^as tight. A convenient nipple should be selected for making- connection to the proving- pump (an ordinary auto pump will do), and every other opening or fitting should be tightly closed. The pump may then be connected and air forced into the system imtil the pressure .gauge registers 14 or 15 pounds. The pump should then be shut off. leaving the gauge under press- ure. Tile extent of the leak may be judged by the rapidity of the fall in pressure ; but its location must be found by following the pipe line and listening for the hiss of escaping air and by apply- ing soapy water to the joints, with a heavy brush. The oxycetylene welding and cutting outfit is the best tool for making the pipe connections, for with it the pipes may be cut to any length, heated for bending, and the joints welded. The welded joints will never leak or give trouble whereas screwed joints might leak. After the pijjcs have been thus ins])ected and proven satisfac- tory, the i)ressure mav be released, the generator startet harmful nor e.x])losive itmay be a source of danger, if allowed to blow against the clothing while the torch is being used. 74 OXY-ACETYLENE WELDING AND CUTTING If oxyi^en is blowino- against the clothes they are extremely inflammable and will ignite Avith a small spark from the torch, the flames may extinguish themselves by evading the oxygen, but a bad burn may result before this is done. Read Instructions: — Carefully read all the instructious attend- ing the apparatus, go over each piece and understand it before attempting to use it. This may save long delays and much correspondence, for it is not an uncommon thing for manufac- tures of welding apparatus, to receive complaints that the torch would not work, the tips would not flt. or that parts were miss- ing and after long correspondence, learn that the apparatus was all right ; but the customer had neglected to read the instruc- tions and (lid not know how to assemble his equipment. Weldijig Tabic: — Aside from the work benches and tools, one of the first requisites of the welding shop is the welding table. Whenever the work to be welded is not too large or too difficult to manipulate, the operation is best carried out on a table. These tables should be entirely of metal except the top which may be made of a good grade of brick, preferably fire brick. The nature of the work to be handled on them, will, of course regulate their size ; but a table 4 feet by 6 feet and 24 inches high will be best suited to the average run of work. For light welding on aluminum work they may be made a little higher, T,T, inches being a good height. These tables are best built of 2^/2x2^x3-16 angles assembled and welded with the torch. The welded joints give the lal)lc rigidity and make the beginner familiar with the work. The material required for the table described above would consist of 4 pieces of angle 6 feet long. 4 pieces 4 feet long, 4 pieces 2 feet long, and 7 pieces of lightei material 43 inches long. The 6 and 4 feet lengths are welded together at the corners with one leg of the angle standing verti- cal and the other projecting inward, making two frames 6 feet bv 4 feet out side. One of these frames is used for the table top and the other for a tool tray beneath. The 2 foot lengths are used for legs, fitting the inside of the angle over the corners of the frames and welding them. The bottom of the tool tray should be about 10 in. above the floor and fitted with about 16 gauge steel sheet. The 43 inch lengths will be spaced 9 inches OPERATING PLANTS 75 apart and welded between the edges of the angles forming the table top. The top of the horizontal leg of these angles will be flush with the horizontal leg of the angles forming the table top, and the vertical leg will extend below^ Their purpose is to sup- port the brick filling, composing the top, and for that reason thev should be placed beneath the joints of the brick. Figure 2^^ shows one of these tables with part of the brick removed to ex- pose their support. Fijr. •2:', WELDING TABLE CONSTKUCTED OF ANGLE IKON On these tables, there can be built, tem]iorar\- ])reheating furnaces for heating work preparatory to welding, or they may be designed to include permanent furnaces formed in the brick work of their top. Here is an opportunity for the welder to display his ingenuity in designing a combined table and pre- heating furnace. Some manufactures build a combination table, or more cor- rectly, a combination tool consisting of an iron table top witli slotted holes for clamping down work, a long \ bar, blocks for aligning and welding crank shafts, and a swivel vise lor holding irregular shaped pieces. The top portion of the stand incorporates a ball and socket joint, which permits rotating the work or clamping it at any angle that will facilitate easy manii)u- lation. The tool is a great convenience and may be classified 76 OXV-ACETYLENE WELDING AND CUTTING among the time saving' devices that go to make np an up-to- date shop. Fi.u. COMBI NATION W DINC TAHIJ-: Preheating Furnaces: — For reasons, which will be described fully under the chapter on welding, any welding shop is in- complete without some provision for preheatino- and slowly cooling his work. In the absence of a special furnace one should always have the material at hand for building a temporary af- fair of brick and sheet asbestos. These are very quickly and easily constructed and serve their purpose very well. Even when shops are equipped with permanent preheating furnaces, there will be occasions when special furnaces will be required for s]>ecial work, and in view of this fact it is well to describe the method of their constructitJU, so the beginning will be prei)are(l when the occasion comes. Ihiilding a h'liniace: — The article to be heated is placed on one of the brick topped tables, previously described, and blocked up with brick. Around this is layed a course of brick about six or eight inches awa}" fmm the article, and ])laced end to end with a space of about an inch and a half between them. These spaces are for air draft and on rare occasions it may be neces- OPKRATIXG PLANTS 77 sary to remove a brick from the talkie top, to admit air to the interior. On top of this course are piled other brick, built nke a wall to a height a little above the top of the piece to be welded. The fuel used is charcoal, which is made into an even bed all around and beneath the article. Sheets of ^i^ inch asbestos are layed loosely over the whole furnace and the charcoal ig-nitei through the holes at the bottom of the wall. The article should be arranged so that the part to be welded will be ui)i)ermost. Then when the pro])cr temperature has been attained, an open- ing can be made through the asbestos and the weld finished without removing it from the fire. \'ery often gas burners may be procured, from the dealer, which may be connected with the acetylene pipe and found very convenient for preheating. It may be added that burners de- signed for city gas might not give satisfaction when used with acetylene. If one intends to equip with preheating burners, it is best to procure burners designed for the gas he intends to use. Protecting Apparatus: — Oxy-actylene cutting and welding apparatus are not classified among the delicate instruments that are liable to become dearranged and out of order: l)ut thev de- serve and require care. They are designed to maintain the purit\- of the gases. To generate cool and commercially pure acetylene at a continually uniform pressure and deliver it to the torch in the same con- dition. The oxygen is reduced from an extremely high pressure to a very low one and this reduction is regulated to a nicet\ . The torch mixes these gases in exact proportions and burns them in a small but exceedingly hot flame where the gases are completely burned and none escape unconsumed. The manufacturers of carbide, from which the acetylene is made, exercise the greatest care to secure and use none but the most pure material; and the manufacturers of oxygen struggle to maintain a standard whicli does not vary three tenths of one percent, from perfectly pure gas. The manufacturers go to all this trouble because tliev un- derstand and know that such precautions are necessary to pro- duce the best results in the welding shop, and tliese details have 78 OXY-ACETYLEXE WELDIXG AXD CTTTIXC) been mentioned here to admonish the welder to keep his apparatus clean and protect it from harm, for it is not reasonable to pre- sume that good work may be done when the appliances are kept in a careless or slovenly manner. All acetvlene p^enerators use water in their operation and for that reason they must be protected from freezing. The quantity of water is proportioned to the amount of carbide they hold and if the sediment of carbide is allowed to accumuhite in the bot- tom of the generator it reduces the water capacity and causes other irregularities in its operation. It is therefore a gool rule to never fill the generator with fresh carbide until after the sludge has been cleaned from the bottom. Oxvgen is stored in the drums under very high pressure, and if this pressure is suddenly admitted into the regulator, it is liable to injure the mechanism of the regulator, or pressure gauges. The valve on t()[) of the oxygen drum should therefore be opened slowh- and left wide o{)en while in use. OPEX THE VAI,\K ON TlIK ()XV(;i:X DIU'M SI.OWI.V Before opening this valve it is well to liave the adjusting screw on the regulator, unscrewed until it is quite free and other valves closed. OPERATING PLANTS 79 Hiere should be some arrangement to securely hold the oxy- gen drums in an upright position, for on account of their narrow- base thev ma\- be easily knocked over and in this event the valve is liable t') be iniured. B-a K'K.\I()\AHI>K MASK FOIJ O.WCiKN DRl'MS Some manutacturers provided a removable base which may be api)lie(l to oxygen drums to prevent their upsetting. This a])- pliance allows more freedom since the drum is not confined to any particular location for securing, but may be moved about at the welder's convenience. When welding over a ])reheating fire, where the article being welded is imbeded in glowing coals, it is good practice to shield the torch from the direct heat of the fire, w^ith sheets of asbestos. 'The first time the torcli is used over the direct flare so OXY-ACETVl.KXK WKLDTXG AND CUTTINa of the fire there will probahly be no perceptible harm done to it: but a repetition of this practice will, in time, damage it. Flashing Back: — While the torch is overheated in this way it may cause temporary annoyance by flashing; back. This annoy- ance may be removed by cooling the torch in water. If in the course of the work it is desired to cool the torch in this way, the acetylene should be completely shut oft' and the flow of oxygen reduced to a very small amount. The object in leaving a small flow of oxygen is to prevent water entering the torch, by the eflux of gas from the tip. The propagation of the oxy-acetylene llanie is about 330 feet a second. This is the speed at which a flame will travel through a tube containing a proper mi.xture of oxygen and acetylene. If the g"ases are not expelled from the tip of the torch at a speed equal to or greater than this, the flame will follow back through the tip into the chamber where the gases are mixed and the torch is said to "Flash T.ack." While the gases arc l)urning in the torch, it is not an imusual occurrence to see long, slender, yellow streaks of flame shoot from the tip. If the torch is permitted to do this fre(|uently, or t(^ continue burning in the head for a short time, it damages it and makes a repetition of this "Flashing Rack" more probable. The gases should therefore be turned off immediately, shutting off the oxygen first. The "Flashing Back" is more usually caused by an insuft'icient gas pressure, and if both gases are turned on a little stronger, and the tlame readjusted to "neutral" the trouble will usually cease: l)ut insufficient pressure is not the only cause which may effect "Flashing Back." If the torch is held close enough to the work to impede the flow of gas, it may "Flash Back ;" but in this event, other conditions being" normal, it should relight when it is with- drawn. If the tip is mutilated or roughened inside or at the end it ma\" produce eddy-currents that will cause "Flashing Back;" or if the torch is held too close to melted metal, the force of the gas may splash the metal into the tip and ])roduce eddx- currents that will cause the same eft'ect. Clean Hose: — Oxygen will not burn. \n the presence of sub- OPERATING PLANTS 81 Stances containinj;- carljon or hydrot^x-n it max produce flanie ; but it is tlie carbon or hydrogen wliich Inirns. and the oxygen supports conil)ustion. If the oxygen hose are allowed to lay around on a floor that is soaked with kerosene or lubricating oil. the oil will creep into the end and when the oxygen is turned on. the hose will he liable to burn. This can cause no further damage than to destroy the hose, for if the oxygen and oxygen drums are pure and clean. the tire can not enter the drum. Acetylene is a carbonous gas and may leave slight deposits of carbon on the inside of the acetylene regulator and hose, if the acetylene regulator and hose are used in the oxvgen service they are liable to be damaged by the combustion of these carbon deposits. .Icctylriic III Dniiiis: It has been explained under the chap- ter on chemistry that acetylene under high pressure might be- come dangerous to handle : but dissolved acetvlene in drums. under ])ressure. has extended the u.sefulness of the gas to a won- derful extent. Acetone is a hydro-carbon and the product of dis- tillation of wood. It is a colorless, inflammable tlnid and is much used in the manutacture of chloroform, iodoform, and other medi- cal preparations. This long known Init rather tni familiar lluid is an excellent solvent for acetylene, which dissolves in it as freely as sugar does in water. The solubility increases with pressure and at atmospheric temperatin-e and pressure it will (lis.solve 24 times its bulk of acetvlene. This j)henomenon is utilized to the great advantage of the welder by dis.solving acetylene in drums of acetone. The drums suijplied are 33 inches long by 8 inches in diameter and contain 100 feet of acetylene. They are perfectly safe to handle, conven- ient for portable purposes, give no trouble b>' freezing, and the gas is cool, clean and dry. Since the gas issues at a high pres- sure. It is necessary to employ a regtilator to bring it down to the pro])er working pressure. Portable Acetylene Dniin Plant: — A small but very conven- ient plant, in which dis.solved acetylene is tised. is shown in figure Xo. 27. This |)lant consists of two dnuns of oxvyen and 82 OXV-ACETYLENI-: WELDIXG AND CUTTIXG two of acetylene with the necessary complement of torches, reg^ulators and apparatus to make up a complete outfit. One drum of each oas is mounted on a truck for convenience in mov- in.q- and the other two drums are used for storage. The plant is always ready for use and while the acetylene costs a little more than in the generator plants, it is perfectly practical tor the man who does only a moderate amount of work. A paragraph on cotmecting and operating a plant of this de- scription will not he out of place. The numhers and parts re- lerred to will he found in figure Xo. 27. t'OHTABlJ-; IVLAXT ISIXG DISSOLVED ACETYLENE OPERATING PLANTS 83 Connect the oxyi^en reijulator No. i to the valve Xo. 2 on the oxygen drum. Then attach the black oxygen hose to the regula- tor and the upper valve No. 3 on the torch. Connect the acetylene regulator No. 4 to the valve No. 5 on the acetylene drum. Then attach the red acetylene hose to the regulator and the lower valve on the torch. I'nscrevv the regular handles Nos. 7 and 8 until they do not bear on the spring inside. This will close the regu- lators and i)revent the passage of gas when the drum valves are opened. Now open the drum valves 2 and 5, and the torch valves 3 and 6. Screw in the handle on the acetylene regulator until the gas begins to flow and adjust the flame, as will be described in Chapter No. ii. The apparatus is now ready to use for welding. When not in use the connections may l)e left intact with the valves closed. Portable .Icctylciic Generator: — A portable generator plant is provided for welders who prefer to take advantage of the saving that may be effected by generating their own acetylene. The plant consists of a generator of 25 or 50 pounds capacity mounted on a four wheeled truck with two ox\gen drums and usually provided with a tool box for supplies and small apparatus. One of these plants is show^n in figure No. 28. It will be connect- ed and operated much the same as the plant just described excei)t that the acetylene regulatr)r will of course Ix" attached to the gen- erator instead as directed in the previous paragraphs. Two colored hose are provided to distinguish between the oxygen and acetylene, and it is recommended to use the black hose for the former and the red hose for the latter. Regnlatiiii^ the Charge For Weldings — Purchasers of weld- ing outfits are immediatelv confronted with the ])roblem, of how to adjust their charge for services, to conform with the usual practice. To give explicit directions for making charges would be useless, the location of the plant with references to neighboring towns, shipping facilities, the comparative cost of labor and commodities, the risk attending the work, the urgency of the de- mand, the cost of a new piece to replace the broken one and the cost of gases including freight and cartage, are all factors to be 84 OXY-ACETYLHXE WELDING AND ("UTTlXCx considered in determinin*;- a just charge. A knowledge of how these factors enter into consideration is best conveyed to the be- ginner by ilkistrations. As a rule it is advisable to make a minimum charge, which may range between 75 cents and $1.00. This, however, can not be rigidly adhered to. Fig. 28 roTrPABEK (;exi;kator plant If the welder has his torch lit and can conveniently leave his work for a few minutes to weld a job of comparative insignifi- cance, a charge of 50c might be both just and profitable, but if the weld is to be made on the knotter of a binder, the charge could justly be proportionately higher. For instance if the selling price of the piece is S5.00 and the express charges 40c, the actual cost t)f a new piece would be $5.40. The time required to get this piece from the dealer, might be two days, during, which time the binder would be out of commission. If in welding the old piece, the welder uses 75c worth of gas and one hour's time at 35c it OPERATING PLANTS S5 would actuallv ci)>t him Si.io to do the work but in this instance lie would be amply justified in a charge of $4.00. To determine the actual cost of work one would proceed as follows. Two drums, one hundred feet each at 2c per foot, would cost $8.00. to this would be added freight and cartage, which might come to $1.00. making a total cost of $9.00 for 400 feet or 2 '4 cents per foot. The acetylene, if purchased in drums, would be calculated the same way ; but if it is generated in the shop, one would consider the cost of carbide. One hundred ])()unds of car- bide at 3;y4C comes to $3.75 plus 40c for freight and cartage makes a total of $4.15 per hundred pounds carbide. This will generate 450 feet of acetylene which ])uts the cost of acetylene at about 9-10 of a cent per foot. From the table, in the back of this book, may be learned the amount of each gas the various sized tips, used during one hour of continuous burning. To find the cost of gas, used on a job, would simply reciuire multiplying the quantity used per hour by the number of hours in use, and that, by the cost per foot. To do a certain job of welding, we will suppose it required 3 hours time. <)() feet of oxygen, 87 feet of acetylene, 10 pounds of charcoal, and one pound of welding rod, and it is desired to figure the cost. A tyjjical procedure would be as follows: 3 hours time, at 35c $ T.05 i)0 ft. oxygen, at 2 '4c 2.02 87 ft. acetylene, at ic 87 $ 3-94 Double for ii\er head charges 2 $ 7.88 I 11). welding rod, at loc to 10 lbs. charcoal, at !c 10 Total cost $ 8.08 50% ])rotit I m work .• . . 4.04 Charges for work $12.12 The purposes for doulTling the cost of labor and gases for 86 OXY-ACETYLENE WELDING AND CUTTING overhead charg^es. is to cover the cost of maintaining- and operat- ing the shop, inchuHng rent, heat, Hght, insurance, bad ac- counts, etc. OXVGEX ACETYLENE WELDING C(J. TIME CARD Job. Xo Date Tag Xo Workman Tag No Tag No Tao- No I Irs. 1 .abor I Irs. C )\crlime Ti]) Xo ilrs. 'V\]^ Xo Hrs. Ilrs. Oil Torch Lbs. Charcoal Lbs. Asbestt)s L])s. .\sbestos Cemenl LI)s. Cast Iron Lbs. Steel Lbs. -Muminum Lbs. llronze Lbs. Copper Misc. Material ... . Description of work Fig. 29 COXYENIENT Tl M K CAKI) FOl? WELDING SHOPS chapti-:r X. WELDIXG RODS AND FLUXES. llic Theory of Fhi.vcs: — Fluxes are used to clean the sur- faces ot the metals, to remove or ]irevent the accumulation of im])urities hy unitini;- with them hefore the\- combine with the metals, and snmetimes, to lower the meltinj^- tem]K'rature. The action is ])urely a chemical one and the task of ]irei)arinL; i>r ])re- pariuiL;- or prescribing- suitable thixes for the A.arious metals, should on]\ be uudertaken l)y one who is thorou,uhl\- familiar with their chemical reactions. The physical and chemical i)roperties of the \arious metals are so differeut that a tlux which would be suitable for weldin_y one material would be ruinous to another. To illustrate. ])hos- phorus contained in copper alloys, increases their strength and toughness; btit one tenth of one per cent in steel causes it to be very brittle. J'hosphorus has a great attinity for oxygen and when incorporated in melted copper, it will unite with the ox\- gen which tlie copper absorl)s. and burn out taking the oxygen with it ; but with iron, for which phosphorus has a greater aftinitv. this is different; when phos])horus is incor])orated in melted iron it does not combine with ox}gen. but remains in the ir<»n and makes it brittle. The Theoretical t1tix f(tr each of the metals would be a sub- stance that would combine with the gaseous im]:»urities which are l)rought in contact with the melted metal, and after combining, will be liberated and jxass ott as a gas. or form a slag that will lloat on the surface. Since the service of a dux is in chcmicalK- uniting with objectionable ini])urilies and remo\ing ihem, and since this chemical union can only occur in a deiinitc proportion, it follows, that if more dux is used than will chemically imite with the element to be removed, il will be free to luu'te with something else and become a new objeclion. b'or this reason lluxes should l)e used strictl}- in accordance with the instructions given I)\- the manufacturers. The gaseous impurity, usually combated 1)\- duxes is oxygen; but in st)me metals, such as. copper. l)r()nze, and ahuninum, there are other gases that may be absorbed unless their absorbtion is pre\enled by the presence of a suital)le tlux. In instances of 88 OXY-ACETYl.EXK WELDING AND f'T'TTINC this kiiul tlie formula tor the fluxes, are sometimes quite compli- cated and to avoid the excessive use of certain chemicals they are frequently incorporated in the welding' rod. Then by using these rods with the fluxes designed for them, the gases are C(^mpletely absorbed and eliminated. To weld 7cr<)Ui^J}t iron, stcrl castiiii^s. steel plates and foi'i^- iiii!;s, no flux should he re(|uired ; but a special steel welding rod is furnished in wliich the metaloids are combined in the right proportion to gi\e the best results. Cast Iron re(|uires a tlu.x to destrox the oxide, which is less fusible than the metal, and which interposes itself in the welds and prevents the perfect joining of the molten metal. The action of the flux is to lower the melting temperature of the iron oxide, which will then Moat to the surface where it may be removed. The welding rods should be selected according to their sili- con content. The right proportions of silicon tend to eliminate the oxide from the iron. Coppers — When copper and the copper alloys are melted thev absorb oxygen, hydrogen, and carbon dioxide gases and to combat these gases is a problem that has not been solved imtil recentlv. The first attempts to absorb these gases into flux re- sulted in changing the texture of the weld: but today the manu- facturers are supplying a flux to be used with a special welding rod. and the results obtained with them are eminently satisfac- tory. It follows from what we have just explained, that the manu- facture of welding materials containing deoxidizing elements, is extremelv delicate, and necessitates rigorous supervision and con- trol. Welders who use the oxy-acetylene process in manufacturing and repairing, are by no means disposed to analy/.e or examine micrographically, the materials they are putting into their welds, and since these precautions are necessary to the production of reputable welding materials, it is w^ell to shoulder the respon- sibility on a trustworthy manufacturer whose success depends on your success. The selection of rods and fluxes for the dift'erent metals will be treated fully under the subject of welding. 89 CHAPTER Xr. GENERAL NOTES OX WELDING. Time used in prepariiit,^ for the weld is well spent. In a few days, a welder can acquire sufficient .skill in handlino- the torch, to perform a fairly g-ood weld, under favorahle circum.stances ; but to do equally good work under any circumstance, requires thought, study and experience. The priiuary object is to secure a weld that will he homc- i^-enous in texture, free from blow-holes, hard sjjots or scale, void of internal strains, and to leave the piece free from distortion. The first three features mentioned are obtained in the actual per- formance of welding-, and will be treated fully in a later para- graph, but to leave work, void of strains and distortion re(|uires preparation in the way of ])reheating. Clcaniiii:;: — It is unnecessary to s])end much time in ck'aning, scraping, or brightening the ])art to be welded, as woidd be re- (|uired for brazing or soldering. The only requisite in this line is to remove the mud or grease by wiping. Other impurities burn or are melted and float to the surface where they may be scraped oft with a rod. Hc-c'cliiii^-.' — If the piece to be welded is thicker than y(i, of an inch, some time and advantage may be gained by beveling the edges, to enable the llamc to entci- between them, .-md the weld started at the bottom and built up. In pieces thinner than j/s of an inch, it is only necessary to sej)arate the edges about 1-16 of an inch, to obtain the same advantage. If the pieces are verv thin, like sheet iron of 14 gauge and lighter, they are liable to give some trouble by warping and buckling, and as the welding con- tinues there may be a tendency for them U) overlap each other. If this overlapping is permitted it will not only make the operation of welding more difficult, but it wall destroy the intended shape of the article being welded. The operator should, therefore, care- fully watch that the edges do not overlap, and if they can be bent up at right angles to a height of 1-16 of an inch it will make the work much easier. The bent uj) edges are melted and furnish welding material. 90 OXY-ACETYLEXE WELDIXG AXD (TTTIXO The amount of advantage gained in beveling, dei)ends on the thickness of the piece, and the method of beveling. The object being to enable the operator to melt the material in the bottom and sides of the fracture and fill the gap with new material melted from the end of the welding rod. To secure a tborough and strong job, it is easily understood that ibis ])n)cess must iuclude the whole fractured surface, otherwise there will be a portion un- welded. and unless the edges are cut away or beveled, it will be necessary to melt the material and blow or scrape it out. to be certain tbat the welding includes the entire fractured surface. Fig. 34 and 35 show the method of beveling i)ieces y^ inch to j4 inch thick. PRACTICAL M Figures 34 and .35 MIOI) OF BHYEEINC THIN I'lKCKS In work of this kind it is practical to bevel one side only : Init in thicker material, if access can be had to the reverse side, a saving mav be obtained by beveling both sides as shown in Fig. This can not always be done, for the reverse side may not be accessible ; but the work and expense is reduced about one-half and there is greater assurance of a thorough weld, when the work is done from both sides. The beginner is very liable to sacrifice good work for neatness and appearance. It is much easier to do a neat looking job by simply welding on the surface; but this ])ractice is positively to be condemned, and although a deep weld may look scattered and irregular the beginner should train him- self until deep welding becomes instinctive or habitual. GENERAL NOTES ON WELDING 91 MKTHOI) OF BEVELING THICK I'lECES A weld which is nuulc from l)()th sides will look neater hecause- the hreadth of the fused surface will he narrower, and it can l)e more (|uicl\l\- fmished. hecause the area of the cross section throuj^h the weld is only half as Li'reat, conse(|uently there is only half as much metal to melt and till in. 'Jdiis is more clearly illus- trated in l'i,ys. 37 and 38. Fiiiuros Ml and oS JLLl'STK'ATJNG Til K KCONOMV OF BFVELING ON BOTH SII)1> m which the area is divided into triangles having ccjual area. This illustration is self exi)lanatory, it heing necessary to merel\ coimt the number of triangles in each figure, to ascertain the com])arative areas. /'rccaiitioiis Jx'ci^^ardiiii:; JLvjnnisitur. — The phenomenon of ex- ])ansion is exi)lained on i)age 32 under the chapter on ])hysics, and it is here proposed to explain to the welder, how this ])he- 92 OXY- ACETYT.EXE WKT,DTXG AND (TTTIXG nomenon may effect his success or defeat according' to his under- standing, and preparation to provide for it. When metal is heated it will expand and there is no evading it. Sometimes trouble occurs when expansion is taking place. At other times it does not develop until after the metal com- mences to shrink, or resume its original proportions. The re- sult of expansion and contraction often produces the most unex- jiected effects, and the welder is admonished to give this subject much earnest thought. No text book can tell him what may happen or what to do on every occasion that may develop during his welding career; these are things that must be studied out 1)\ himself, and his ultimate success depends as much on his ability to overcome the effects of expansion as on his ability to handle the torch. So do not pass this subject until you are thoroughly determined to observe, study and solve the capers that expansion will play with you during your earlier efforts. Sometimes the effect of expansion can be ignored, and the welder \\\\\ soon learn bv experience, when this will be true. .\ good illustration of this is in figures 39 and 40. 2^— '- Fijiurrs :;SI uii.l W KFFKCTS OF FXI'AXSTOX AXD COXTKACTIOX In Fig. 30, no bad effects of expansion are to be feared be- cause the ends are free to move and extend or withdraw. On the contrary in Fig. 40 the same bar having the same break, is the center member in a two panel frame. What will be the eft'ect GENERAL X0TE8 OX WKLT^ING 9:t of expansion in this case? As the metal in the vicinity of tlie weld becomes heated it will expand. The ends being a part of the frame at 3 and 4 will be held in their normal position ; but the melted portion surrounding the weld will offer no resistance, and the expansion will i)ush the melted ends closer together in the weld. When the job is finished, and the metal begins to cool otT. shrinkage takes place and the center bar shortens. Tf the metal is elastic or ductile the shrinkage may not cause a break, but will cause a strain or deformation of the frame. This would probably be the case with mild steel; but with cast iron, it would likely cause a break in the hottest place, which would be in the newly welded portion. Xeglect to provide for expansion would therefore cause failure. Copper, alumimun. cast iron, and those metals that are weak- est when hot, will usually break in the weld. ( )n rcHection. it will be observed that, to make a success of this job. it is only necessary to preheat the portion of the frame, indicated at i and 2. then on cooling the shrinkage will be ecpial in each of the parallel bars, and no break or distortion will result. If it is impossible to heat the frame, as described al)ove. other methods are at the disposal of the welder; for example, a slight spreading of the two bars 3 and 4. to the position indicated In the dotted lines. 'J1iis may be done with keys, wedges, or jack- screws, and the efifect is to separate or spread the fracture. While making the weld. ex])ansion takes place, as described be- fore : but when the weld is finished and shrinkage commences the wedges or screws are removed, and as the center bar shortens, tlie sides graduallv resume their former i)osition, and the frame is \-oid of strains or fracture. .\nother method, which is not especiall}' recommended ex- cei)t on rare occasions, is to cut the frame at 5, then weld the fracture and the cut will acconnnodate the expansion by spread- ing, then after the center bar has been welded and shnmken, the cut in the corner can be welded, where the cft'ects of ex- pansion and contraction need not be feared. There has recentl\' come into use. a method of restricting the expansi(^n to a verv limited portion, resulting in the ex- 94 OXY-ACETYLEXE WELDIXG AXD CUTTJXG pansion being- so slight that it may be ignored. This is done by allowing the portion immediately surrounding the weld, to attain the required temperature ; but preventing the heat spread- ing, which of course will reduce the expansion, by cooling the surrounding portion with water. If restricting the amovuit and extent of expansion is all that is to be desired, this method might give satisfactory results: but there are other causes that may produce failure. One of these is chilling the metal. For reasons that will be explained later it is desirable to have the weld and surrounding metal as liot as it can be made without changing its shape, or texture, and if the cooling method is used to eliminate expansion, the heat of the portion being welded, W'ill be conducted away, and it will be impossible to maintain a temperature that will give the best results. The Economy of Preheating: — Preheating is essential as an economic measure. To properly execute a weld, the sides and bottom of the fracture must be melted, and if the metal is cold it will re(|uire more of the welder's time, and more gas to bring it up to the melting temperature, than if it had been ])reviously heated with a cheaper fuel in a manner that did not require the constant attention of the operator. Therefore, to obtain the greatest measure of economy, the piece to be welded should be placed in a preheating furnace, and allowed to heat up while the welder is doing something else. Preheating to Eliminate Defects in the U'eUT. — It has been explained under the chapter on metallurgy called "Metals and Their Properties." that, when melted cast iron or high carbon steel comes in coiUact with a cold metallic surface, it chills and becomes so hard that it cannot be machined or filed. It is not an uncommon thing to find hard spots in a cast iron weld, which have been caused in this way. Cast iron contains more impurities than any of the ferrous group, and when it is melted, these impurities form a gas and, if the metal is sufficiently fluid, they will float to the surface in bubbles and be liberated ; but if the melted metal is not per- fectly fluid, these bubbles will remain in the bath and show blow holes in the weld. GEXKRAL XOTHy OX WELDING 95 In lieavy sections of cast iron that have not been preheated, the melted metal is chilled so rapidly by the surrounding cold portion, that it cannot be kept sufficiently fluid for these gas bubbles to raise. Considering the foregoing it may be said, that the ])ractice of preheating cannot well be eliminated. Hcrw and Where to Preheat: — An article like an automobile cxliuder or motor frame should be heated throughout, so that the whole ])iece will be hot and expand in all directions alike. This is also true of any other small intricate piece that may become badly distorted or broken 1)\- unequal expansic^n : but in the case of a large flywheel or gear, with one or two broken spokes, it would be cumbersome, expensive and unnecessary to preheat the whole wheel. T.arge articles of this nature are only preheated in a portion which must be selected according to the location of the break. This ])orlion will usually include the hub and a little over one- half of the rim. including llie broken ])ortion. The preheating furnace for thi^ kind of work will be a temporary afl:'air built of looselv ])iled l)rick. with an asbestos covering. One side is semi-circular, and follows the contour of the wheel, and the othei side is straight, fitting around the spokes and rim. The arrange- ment of air drafts nuist accommodate the nature of the work. . hi j list i lit:; tlie l-laiiie: — (Jne of the tir>t things the welder will note, is the i)eculiar appearance of the tlame issuing from the ti]) of his torch. When this is in normal working condition there will be an inner white llame of dazzling brightness, surrounded bv an outer tlame of a pale bluish tinge, with a wide yellow- border. When this iiuier flame is at the maxinuun size attainable, and has a clear distinct outline, the flame is said to be neutral. That is. it will have neither an oxidizing or carbonizing eft'ect on the weld. With very few excejitions. this is the kind of flame that should be obtained before starting to weld. Manipulating the valves to i)roduce this kind (»f flame is called adjusting the torch. The method of ])roce(hn-e. to attain this adjustment, is ilescribed as tollows : After connecting the torch and regulators as described in chapter 8. the operator will see that all valves are open except 96 OXY-ACETYLENE WELUIXG AND ('I'TTSXG those in the ret^ulators. these will he closed hy unscrewing the handle until it is quite free and does not hear on the springs within. Starting from this i)ositi()n the oiK-rator will screw in the handle on the Acetylene regulator until the gas begins to flow, and then ignite it. C\)ntinue to screw in the valve handle, imtil the base of the tlanie ap]iears to leave the torch and stand away about an eighth of an inch. The acetylene flame is now a large, flaring, smoky, irregular shaped mass: but screw in the handle l) NOT DHll' l.XTU Till-: WKl.D. The torch should be held so that the end of the white tlame is ''8 to Yit. of an inch away from the work, the distance lieing proportional to the size of the tip and the nature ai the work. For a medium sized Up a good average distance would be '4 of an inch. P^xtreme care must be taken to not ^XMUiit the cud oi the ti]) to touch the melted metal, or to allow the melted metal to s]ila^h into the tip. 98 OXY-ACKTYLENR WELDING AND CUTTING Movements of the Torch : — An advantage may be gained by giving the torch a sHght circular movement to (hrect the tlame rotativelv against one side oi the weld, back onto the welding rod, over to the other side of the weld, then forward onto the unmelted portion and thus continue in a series i>f little circles, of uniform size and regular fre(|uency. The diameter of the circles should be nearlv eriual to the l)readth of llio weld. Fig. 42 ('IKM'[-LAK MOVK.M K.NT i)V TORCH FOR WORK OF MKDIUM THICK XKSS lu>r welds of greater thickness a side to side movement may give better results. The amount of the movement correspond- ing with the breadth of the weld, and regulated in time to the melting of the sides. These movements are however only sug- gestions, and the welder nnist decide for hini'-elf what course he will pursue. GEXEEAL NOTES ON WELDING 99 SIDK TO SIDK MOVK.MKXT OF TIIK TORCH ?^0R HKAVIKK WKLDS There are certainly manipulations to be learned, but they are relatively easy to acquire, and are better obtained by practice than by reading". The beginner usually does not melt enough and the weld lacks penetration, or he melts t(M) much, and so makes holes. It is evidentK necessary to tliid a ha]ipy medium, and al>ove all to work regularly. F/7//H_i[ /';; Holes: — Holes arc particularly despairing to the beg^inner. because in trying to mend them, he usually sees them enlarge. A few instructions on tilling these holes will be appro- priate here. The flame should be inclined until it is almost parallel with the surface of the work and directed against the edge of the material. As soon as the metal begins to get plastic, a little metal is welded to the edge, from the welding rod. Con- tinue this process until the hole is filled. The principal difficulty encountered in this work is to regulate the heat so that it will not melt the edges away or cause the welding rod to drip through the opening. 100 OXY-ACKTYI.?:XK WKLDTXG AND CUTTING / Fii:. 44 I'OSITIOX OF TOl.M'II FOIx" Fll.LIXC TIOLKS Dcfccfs of Welds: — During- the i)rocess of welding- there are several defects that may develi>i) and to a\oifl tlieni the welder is admonished to he constantlx alert to the canses that ma\- ])ro- (hiee them. The first, is lack of i)t'netration. This more frecjuently takes l)lace when the edges of the weld are not heveled : the heat has not been stifficient to melt through the metal, and the original crack shows on the reverse side. This not only effects the solidit}- of the weld, but affords a starting pt^int for a new break. To avoid this defect, one must not go to the other extreme and melt holes through the piece, for these holes cause loss of heat and time, and assist oxidation. Next there is adhesion. This very significant term is difficnlt to explain. One obtains adhesion in different ways, either by not sufficiently melting the edge of the weld, or by doing so un- equallv. It mav also be done by flowing melted metal onto parts that have not been previously melted, or have cooled off, and again by inter])osition of oxide in the bath. Welders should exercise constant care to avoid ""adhesion'' for it is not rare to find this defect in welds made l)y experienced workiuen. ^Melted metal flowing from the edges of the weld GEXEEAL NOTES OX WELDING 101 into the bottom, will cause the same defect, if the bottom i> not melted. There are sometimes bad joints due to the interposition of a layer of oxide between the old and new metal ; this is gen- erally due to piliuo- melted metal on metal that has solidified, or to lack of liquefaction in the molten bath. l)low holes frequently form in the weld and the stren,<^th of the joint suffers accordinoly. These blow holes may be due to lack of i)reheating;, to absorption of sj^ases. or to blowing air into the melted metal with the torch. The elimination of the first two defects will be treated under the subject of welding the different metals. We nuist mention lastly that welds are sometimes insufficient- ly filled. The level of the weld does not reach the surface of the piece. Such defects are attrilnited entirely to carelessness. IVcldiiii^ Wrought iron and Mild Steel: — Wrought iron and mild steel are the easiest metals to weld by the autogenous i)roc- ess. They recpiire no ilux to absorb oxides or i»ther impurities. A steel welding rod is used and by following the instruc- tions given in the preceding paragrai)hs of this chapter, the welder is provided with all the instructions he may re(|uire. The only other thing needed is practice. Welding Cast Iron: — When everything is taken into con- sideration, the difficidties to be overcome in welding cast iron, are neither numerous or iusunuountable. as a matter of fact when cast iroii is projierly welded the joint is stronger than the original ])iece. This is generally due to the sujjcrior (|ualit\- of the iron ])ut into the weld. In the chapter on metals and their properties, we learned that cast iron contained a large amount of carbon. That this carbon existed in the cast iron in two conditions, that is. the combined condition as white iron and in the free or graphite condition as gray iron. We also learned that the gray iron was soft and that the white iron was very hard, and could not be machined. Since the majority of welds in cast iron should l)e capable of being machined, it is indisiiensable that the weld should be in the condition of grav iron. 102 OXY-ACETYLENE WELDING AND CUTTlXCi When welding rods of j^roper consistency are used, a good soft gray iron weld can be obtained by protecting it against chilling while the melted metal is being run in. This may be done bv preheating and pursuing the methods prescribed to pre- vent adhesion. Cast iron requires a flux to destroy the iron oxide, wliicli is less fusible than the metal and which inter])oses itself in the weld and i)revents the perfect joining of the molten metal. The action of the tlux is to lower the melting temjierature of the oxide, which will then float to the surface where it may be removed. The flux is used by putting the end of the hot welding rod into the box of flux and then working it into the weld. Cast iron is ladeu with imi)urities which form gases when the iron is melted. If the melted iron is kept sufficiently fluid these gases will come to the surface and disa])])ear. but if the uietal is iu oul\- a semi-thiid state they will remain in the l^ath and cause a s])ongy weld. This trouble is more noticeable in heavy work, which, if not preheated, will chill the melted metal so ([uickly thai the gases cannot escape. The elimination of these gases may be assisted 1)\' rotating the torch around in a little pool and then gradually withdraw- ing it: l)ut in so doing the welder should be careful to not blow air and gases into the melted metal. Thoroughly jjreheating the casting will also greatly assist in eliminating the blow holes. irddlno; Malleable Cast Iron: — While the process of auto- genous welding is being used so successfully in all the metal trades, many unsuccessful attempts have been made to weld malleable cast iron, and to those who have experienced disap- ]X)intment. an explanation ni wh\- their efforts failed, with an outline of a method by \\liich these castings can be mended, should be of benefit. Malleable castings are first made in the condition of hard brittle, white cast iron and subsequently made malleable by heat treatment. The heating process w'hich converts white cast iron to malleable iron is called annealing, and effects a chemical change in the structure by decarbonization. This dccarbonization is nearly com])lete at the surface and penetrates in a lessening degree toward the center, giving the outside portion the texture (JHNEKAL NOTES OX WELDING 103 of mild steel while the inner ])()rti()n may retain, in a more or less (le,qree. the ([nalities of cast iron. When this metal is re- melted the carl)(>n is dispersed, and the entire mass reverts to cast iron. The o])erator who is used to weldinq- mild steel and cast iron will recall that they are handled dift'erently. That the method used in welding- steel to steel would he useless in welding; cast iron, or the methods emi)loyed with cast iron would he equall\ unsuccessful with steel. That is ])ractically what he is tryini^ to iU> when he undertakes to weld a malleahle casting'. The material is not homogenous. The bottom ])ortinn of the weld being' in cast iron, and the to]) portion in steel, with no definite dividing line between, it is useless to follow tlie method prescribed for either, and to his trouble is added the difficulty occasioned by the diffusion of the elements in the materird melted from the sides of the fracture. It follows that to successfully mend a malleable casting the process employed must not necessitate melting" the sides of the fracture, that the welding- material should fuse at a lower tem])er- ature than the casting-, and that its adherence, bonding' (|ualilies. phvsical strength and ductilit\' should closely resemble the original casting-. After much stud\- and e.\])erimenl. the N'ulcan Process Compau}- and their allied interests in Minneajxilis are having- considerable success in mending broken malleable castings, and a descri|)tion of their methods will uncloubled]\- be useful to others who are em])loyed in the metal trades. In pre])aring the work for mending', the fracture is chij)ped awa\' in the form of a \ groove with the ])ointe(l bottoiu just coming to the surface on the o])posite side. or. if the casting- is thick rmd the opposite side accessible, two grooves arc cut with their ])oinled bottoms meeting in the center. The ))art surrounding- the fracture is then heated with an oxy-acetylene torch to a bright red. and si)rinkled with \ nlcan bronze flux followed bv a few drops of Tobin bronze melted from the weld- ing- rod. If the bronze remains in a little g'lobule the work is not hot enough, but if it s])reads and adheres to the surface, the temperature is right, and the groove shoidrl be quicklv filled. It is nc^t acKisable t<> keep the work hot anv longer than is ueces- ]04 OXV-ACKTVI.KNK WELDING AND CUTTiXG san'. but to make the mend as quickly and at as low a tempera- ture as possible. The behavior of the bronze affords a i^^uide in res^ulatiny- the leni])erature. This process cannot be called autooenous welding-, but a mal- leable casting mended in this way is practically as good as one piece. It has about the same tensile strength and duclilitx as the original and the process has the ad\antage of being very (|uickly performed. ]Veld'nr^ Copper. Brass and Bronze: — Co])per and all of its allovs have a facult\ of al)sorl)ing gases from the t1ame. The oxide of co])per is very solul)lc in the metal and forms, with it, an alloy which crystallizes in the mass and destroys the homogen- eous le.xture of the weld. If the autogenous welding of copper is obtained by melting the edges and adding metal melted from a pure copper welding- rod, there will necessarily be considerable oxidation of the metal and the oxide will remain in the weld. The metal will lose its distinctive properties and be riddled with blow holes. Xo ma- nipulation or regulation of the torch can overcome these defects. It is therefore necessary to use a deoxidizer capable of re- ducing the oxide as it is formed. Since the oxide is dissolved in the metals itself, the use of a flux does not give the expected re- sults. It is therefore necessary that the deoxidizer be incorpor- ated in the welding rod, so that it will be diffused continuously throughout the molten metal. All welds made on red copper, without the use of deoxidizing welding rods, are therefore strongly oxidized and full of blow holes. The tensile strength of copper diminishes rajiidly as the tem- perature is raised and unless the welder uses precautions to re- lieve the weld of strains while it is hot. it will be very likely to crack. These strains may be relieved by heating other parts of the piece. The weld should be prepared exactly the same as for weld- ing iron or steel, and the torch manipulated the same as described before. ( )n account of the conductivity of this metal, it might be ad- visable to use a larger tip, on the torch, than would be used for welding steel. The flame of the torch should be perfectly regu- GKNKKAL NOTKS OX WELDING 105 lated and maintained without excess of either gas, for if either acetylene or oxygen is free in the flame it will be al)sorhed in the weld. r)rasse> and l)ronzes require the same precautions and weld- ing rods as are used for copper; but on account of their con- taining other metals, it is necessary to use a bronze Hux in addi- tion Id deoxidizing welding hkIs. U'cUiiiti:; . Uitiiiiiiuin : — When aluminum is melted it oxi- dizes ver\ freely and this oxide which clings to the surface of the metal, prevents the joining of the new metal to the old. It is therefore necessary to remove this oxide, which is done by scraping it out after the metal is melted. .Muminum melts at a comparatively low temperature and. since the welder is iu)t warned of the approaching melting temperature. 1>\- any change in color, he nnist use care not to melt the whole struc- ture and destroy it. This may occur in the jireheating hre un- less caution is used. Aluminum like copper is very weak when hot and this property combined with the excessive ex])ansion of the metal, is something that may cause the weld to break soon after its completion unless precautions are taken lo remove shrinkage strains, by ])reheating. Some writers advocate the use of a deoxidizing tlux for making aluminum welds; but others believe better welds may be obtained by the "puddle" system of welding than 1)_\- the use of lluNcs. It is the writer's observation, that excellent welds are being made today by the i)uddle system, and since this method is very easily learned, it will be described here. The ruddle System: — Aside from the oxy-acetylcne torcli and welding rods of the purest aluminum, the only tool used is a long slender steel rod. flattened on the end to form a paddle or spoon. This rod is called a sjxatula. Armed with this tool the welder will melt the metal where the w'eld is to be made and with the spatula, scrape off the surface, leaving it clean and bright. This only removes the dirt for. although it may not be visible, oxide forms on the bright surface immediately behind the s])atula. and unless it is bntken up the new metal will not ]o\u. Breaking up this oxide is done after the surface is covered 10(5 OXY-ACETYLENE WELDING AND CUTTING with new melted metal, which protects it from further oxida- tion and is accomplished by o-ently scraping the spatula thnnigh the mass of melted aluminum and removing" it. The operation is somewhat similar to scraping the skin oif melted babbit : the only difference being, that the oxide of aluminum ma\ 1)e mixed with the melted metal. The success of the weld depends en the tboroughness of this skinning or puddling operation. After a little metal is added and thoroughly puddled, more aluminum is melted in and the ])uddling repeated. Tlie precautions to be taken in welding aluminum are sim- ilar to those described before. It is of ])rimar\ importance to never add new metal to a surface that is not in a molten condi- tion. Lead /)//;-///;; 1^ : — The process called burning is used for join- ing the edges of lead sheets or pii^es without solder. The edges are fused to an extent which ])ermits the ])arts to unite and form one solid ])iece when cooled. This i)rocess is known as the auto- genous process, and although it has been practised for centuries, it is used far less at the i)resent day than it should be. It aff'ords a (piick and cbea]) method of making lead joints of the most durable character, and it may be used with profit in many cases instead of the soldering process now commonly employed. Solder cannot be used for joints which are ex])osed to con- tact with aci(l>. because most of the ordinary acids will dissolve the tin. of which the solder is in i)art com])osed. Tanks which are u.sed for the manufacture or storage of acids or acid salts, or for the storage of mineral oils, petroleiuu, etc.. are usually lined with lead. The joints in the^e linings. and in all of the lead pijies which are used for the same purpose, must be made b>- burning. The operation is performed by meltiug the edges to be joined a drop at a time, by means of a torch. It is essential that the flame which is used shall not oxidize or tarnish the metal. If the drop of melted metal does oxidize, it will not unite with the solid parts, and the joint will be a failure. GENERAL NOTES ON WELDING 107 The most certain and convenient way to secure a non-oxidiz- ing flame is to use hydrogen gas mixed with air to supplv the torch. Other methods may be employed, but none are so con- venient as the hydrogen gas process. A FEW EXAMPLES IX WELDIXG. In describing a few examples on w-elding. we will consider that the welder has acquired a knowledge in handling his torch and welding the various kind of materials, so this detail will be omitted, and the illustration confined to a description of the prep- aration incidental to the particular example. Welding a Crank Shaft: — The difficulties is welding a crank shaft as shown in I'igure 45. arc not in the performance of weld- ing; but in providing for exj^ansion and securing alignment, that will oljviate the necessitv of much machine work. Fifr. 4.') CRANK SHAFT ON Y P,I>()('KS I'l.MM'A 1." KD FOR WELDING Before assembling for welding the fracture is ground away to form a \' groove, as is usual in preparing any weld, but in this case there is about an eight of an inch of the fracture left undisturbed. This is to furnish a guide for adjusting the pieces. The shaft is then clamped in \' blocks like those shown in the picture. These \' blocks have a [)iece of cardboard or sheet ms OXV-ACETYLKXK WELDING AND CUTTING iron placed between the sloping- side of the block and the long V bar which holds them. In the picture above these pieces of sheet iron would be on the far side oi the two hl(K-ks shown to the left and on the near side of the block shown to the right and when the crank shaft is damped in position, they would cause an opening to sliow between the fractured ends of the crank shaft. This opening is to take care of expansion and should be about 1-32 of an inch. With the torch, the part sur- rounding the weld will be heated until this space is closed up by expansion, and then the \' shaped opening welded full. Before shrinkage takes place the clamps and strips of sheet metal are removed, wheii this part of the weld become rigid, the unwelded portion on the back is melted out and welded full. IVeldiui:; the Inner Wall of an .Into Cylinder: — .\ portion of the water jacket, outside the fracture, is cut out b\- drilling as shown in Figure 4^). Fig. 46 AITO CYLINDHK' I'HKPAEED FOR WELDING The whole cylinder is then put into a preheating fire with the fractured side up and when suiTiciently heated the covering is laved aside and the fracture melted away with the torch and GP:XP]EAL NOTES OX WELDING 10{> welded full. The piece which was cut out of the water jacket is then welded back into place. For convenience in holding this piece in j)lace while it is being- fastened, a small rod may be welded in the center, to form a handle. \VELDI.\(; ATTO SPRIXC.^. The usual method in welding" auto springs, is to fi'^st bring; the spring to its normal jjosition and block it up with bricks to hold it in alignment while it is l)eing welded. Then with the oxy-acetylene torch the fracture is quickly melted and run to- gether. The process differs from welding mild steel in the fact that the edges of mild steel plates are separated a short distance to facilitate the flame entering between them, the space being filled with material melted from the welding rod; but when welding- springs, the edges are brought tight together and a narrow strip of the material adjoining the fracture is melted from the top down through to the bottom, adding only as nuich material from the welding rod as is required to restore the normal thick- ness. When this has been done on one side it is repeated on the other : but this time it is not necessary to weld as deep. The portion of the spring, which has just been welded, is a little softer than the rest and is not as liable to break from shock. It is not the custom to retemper this part of the spring for very good residts are obtained without. To make this part of the same temper as the rest, would require retempering the wiiole spring, which is an undertaking not to be recouimended to any one who is not skilled in that line and provided with a .suitable heating furnace and oil bath. Even then it is a treacherous job and better results are usually obtained by leaving the weld un tempered. It is well for the reader to refer to the illustrations on page I, 2, and 7 and note the temporary grates wbicb were con- structed to sustain the preheating fire. ]]0 OXY-A^ETYL^^XE WELDING AND CT^TTIXG CHAPTER Xll. CUTTING IRON AND STEEL WITH THE OXYGEN JET. The rapid combustion of iron in oxygen has been known for over a century and was mentioned by I^avoisier. The chem- ical treatise on this subject mention that iron oxide formed is more fusible than the iron and is detached as the combustion ]>roceeds. ccjntinually exposing' the bare iron to the attack of the oxygen. It is this phenomenon that makes possible the rapid cutting" of iron and steel, with a torch and oxygen jet. and although it has been known so long it was not until recent vears that the ])rocess was used industrially. All thicknesses can be cut from the thinnest sheets to heavy armor plates for battle ships. The process is also being used extensively in steel foundries for cutting the gates and risers from steel castings. In fact the uses to which it may be advantage- ously applied are imuunerable. and as people become better acquainted with it. they are finding new uses for it. ( )n pages 5 and 6 are mentioned a few of the recent applications of this process, to cutting the wreckage of ore-docks and sunken ships. YV/r Theory: — All instructions in autogenous welding cau- tion the operator to use a perfectly neutral flame, for if he uses too much oxygen, he is told, the metal will become oxidized, or burned up. If a small piece of iron, or steel is heated and drop- ped into oxygen it will burn rapidly. The iron actually be- comes a fuel and is burned in the oxygen ; and in burning it generates heat just the same as any other fuel would do in burning. This phen()menf>n which is so carefull\' avoided when making welds, is used to advantage in oxy-acetylene cutting. The torch is arranged to first deliver a hot neutral o.xy-acetylene flame until the metal is at a white heat, then a jet of oxygen is impinged against this hot metal and iron burning or oxidation ensues. The oxidation commences at the part which has previously been heated to redness, because at this temperature the reaction takes place more radiply. The combustion or burning of this CUTTING IKON AND STEEL WITH THE OXYGEN .lET 111 portion of the iron, lil)erates heat, a portion of \vhich is ahsorbed by the surroundini;" iron, and raises it to a red heat, so that in turn it burns, lliis burning- is progressively extended by moving the torch along the line of the cut. This burned iron is known to chemists as oxide of iron and when first formed it may appear as a solid scale adhering to the surface of the iron. If it remain there it protects the iron against anv further oxidation or burning just the same as a thick covering of ashes will sto]) the burning of wood. W'nvught iron and mild steel, melts at a luuch higher temperature than does the oxide of iron. So on these substances the oxide will melt first and run off leaving the surface of the metal clean, and con- tinually exi)osed to the attacks of the oxygen jet. The oxide on cast iron cannot be melted off to expose the clean surface to the attack of the oxygen jet, because its melting temi)erature is higher than that of the metal. It may be melted, but the metal melts first and the oxide mixes with it. The proc- ess is not the clean rai)id cutting action obtained with mild steel, or wrought iron, but is merely one of melting. It is there- fore said that cast iron cannot be cut by the oxy-acetylene proc- ess. This is also true of coi)])er. brass, bronzes, aluminum, and ver\ high carbon steel. Using the TorcJi : — In using the oxy-acetylene cutting torch it is advisable to first adjust the regulator on the oxygen drum to deliver oxygen at fo to 50 pounds pressure, according to thick- ness of the metal. Then turn on a little acetylene, ignite it, and open the needle valve in the b.-uidle of the torch until the base of the flame appears to leave the torch and stands away about an eighth of an inch. The acetylene flame is now a large, flar- ing, smokv. irregular shaped mas>, but open the little needle valve that controls the oxygen supply and the flame will com- mence to assume definite size and proportion. C'ontinue to slowly open this valve and there will ajjpear an inner white flame that blends with a thin feathery edge into a pale blue outer flame, and as the owgen sui)ply is slowly increased this inner white flame becomes smaller, and the outline more distinct. When the thin featlierv outline of this inner flame is cntirelv gone and 112 OXY-ACKTYLENE AVELDING AND CT'TTINO the dividing" line between the two parts of the tlanie is distinct. the oxyg-en supply is sufficient, and the flame is neutral. To start the cutting action, the little white inner flame should he held about three sixteenths of an inch from the metal until it begins to melt, then the thumb lever is ju'essed which starts a flow of oxygen through the cutting tip. \Mien the oxygen comes in contact with the metal it hums it very rapidly, and oxide of iron runs or is blown otit of the cut. When starting a cut in the middle of a plate of steel, there is no place for this melted iron oxide to run out. so it gathers in a little puddle where the force of the torch blows and spatters it. In this event care should be taken to prevent it splashing into the end of the torch. This may be pre- vented by holding the torch a little farther away from the plate than would be necessary in starting the cut at the edge. After the cut is started and there is a place for the iron oxide to escape, the torch may be brought a little closer to the work and steadily advanced without wabbling or tilting, moving evenly along the line of cut as fast as the metal will burn and run out. If the torch is held too far away, the action is slower and the g-ap of the cut is wider, while if it is too close, particles of burned iron may enter the torch. A jerky, wabbly movement makes a ragged cut. Plates, ys or 3-16 inches thick, can be cut with the ordinary welding torch, by first heating the metal to a white heat with the oxy-acet\lene flame and then shutting the acetylene entirely off and using the oxygen jet the same as in the regular cutting torch. The heat of the burning steel is sufficient t(^ cause the combus- tion of the adjoining material and thus the operation is contin- uous without the use of the preheating flame which accompanies the cutting torch. The jerky wabbly movement, previously mentioned, not onl\ makes a ragged cut. but it retards the progress of the cut and adds to the cost of the operation. In consequence of this, there have been cutting" machines designed, which carry the torch at any desired angle and at a uniform speed across the work. To obtain the best results some arrangement of this kind is required. In figure No. 47 is shown a machine of the kind just described, which is designed to cut bars or structural shapes. The piece to be cut is clamped in the \' shaped notch, and the cutting torch. CUTTING I HON AND 8TKEL WJTH THE OXYGEN JET 113 wliich is easily discernahle in tlie picture, is carried steadily across tlie work by means of a screw. A simple device for cutting- elliptical man holes in boiler plates, may be made by providing- a track, of angle iron, formed to the shape of the desired manhole and ecpiipped with a carriage t(^ carrv the torch. The carriage can be of the easiest construc- tion, and ])r(n-ided with three wheels, two of which will ride on the track and one on the ]ilate. i.t:. 4 7 MACHINE \-\)U ClT'l'ING P..\lx'.'^ .WD STK'r( "rC K.\ L SHAPKS The machine shown in ihc following tigure Xo. 4S is designed for cutting circular plates or holes. The heavy base which serves as a center, is held in ])lace by its weight, and affording a hear- ing for the upright stud which carries the horizontal bar. The bar slides through the stud and may be clam])ed in any position that will ijive the retiuired diameter to the circle. After this ad- J 14 OA^-A('KTVI.KM-: WKLDINU AM) CUTTlN(i iustmenl has l)een made, the stud is rotated in the ba>e. by hand. carrviniL^' the torch anmnd in the ])ath of a circle. The torch shown in tliese two ilhistrations i> es])eciall\- designed for nia- clhne nse. MA( I1IM-: FOi; (TTTlNd ( 'I KCl ' l.A i; I'l.ATKS AND OI'KN I .\(JS Structural iron workers, erecting" contractors, and others en- gaged in building or tearing down old structures, find the oxygen cutting ])rocess of great service to them. The saving which re- sults fn)m its use may be judged by the reader, after noting the table of cutting speeds and costs as noted below. Thickness Cost of gas C(t. 2c per foot T inie per of ( )xygen .\cetvlene foot ])late in seconds ■4 $0.0082 i $0.0026 24 / - i 0.0154 0.0034 ; 30 I 1 0.0244 1 0.0042 38 1/2 0.030^) 0.0066 4'> CITTIXC IRON AXi) STK1-:L WITH THE OXVGKN .HOT ] i: Cl'TTINC OLD STi:i;i, I'LOOK' I'.KA.MS Durinq- the year 1914 the old union depot in MiiineapoHs was torn down to make room tor a new l)uil(lin^". All tile structural steel ineiubers in this buildinjn' were reniovetl by cutting- them free, with the oxy-acetylene cuttinq- torch. The above picture was made from a photo, of the cutters, while at work. The process was eminently successful and showed a ij^reat savinj^ over the old method of removing them by knocking- off the rivet heads, or sawiu"-. llf) ox Y- ACETYLENE WELDING AND CUTTING Fiy the new method, the same work was done in thirty minutes at a cost of (S3 cents. Another incident is in welding an outside sheet. On previous occasions it re(|uire(l the work of two men for \f> hours and cost $10.80 to make the repair, which was welded with an oxy- acetvlene torch in 3 hours time at a total cost of $5.85. A cracked sheet, usually required patching and to do this at an average cost of $15.00 was good work; l)ut with the oxy- HOILKR MAKING AND SHKKT ^fKTAL WORK 11!< acetylene process, the crack can be welded and the sheet made as good as new, at a cost of $4.00. The welded crack has an advantage over the patch, in the fact that it only ])resents one thickness of metal, to the action of the tire. This advantage is well appreciated h\' boiler makers. To rednce an old boiler to commercial scrap, recjuired the labor of two men for 80 honrs and usually cost about $40.00. The same work can be done with one man using the oxy-acetylene torch in 73'j hours and will cost, for labor and gas. about $12.00. The question will probably occur to some ])ractical boiler makers, whether an o.w -acetylene welded seam will withstand the action of fire. In answer to this we will cite an inciilent. m Duluth. where it was desired to coustruct a bosh jacket, tor one of the large blast furnaces being built there at that time. It was particularly desired to get a smooth seam, so that the cooling water would stay on the jacket, better than was possible for a film of water to do on such a surface when broken by seams and rivets, and al^o to ha\e only one thickness of metal, to eliminate the great lial)ilit\- of burning, due to double thick- ness. The bosh jacket was in the form of a truncated cone, aiul was eleven feet in diameter at the bottom, si.xteen feet at the top, nine feet high, and made of half inch sti»ck throughout. In fabricating this job it was Iniilt in four sections or seg- ments aufl welded along the vertical joints, with an oxv-acetvlene torch. When the welds were fmished the joints were ground smooth and were hardlv percei)tible. The job was eminentK- satisfactory and in several years of continuous >er\ice. has shown nc) indication of weakening at the welded joints. Welding Pieces of Piffrrciit Tlilchiicss : — ( )xy-acetylene weld- ing is not easilv applied to ])ieces of dit'lerent thickness, because the melting of the two edges is not equal, and does not take jilace at the same time, .^ince the torch is too powerfid lor the thin ])iecc or too weak for the thick |)iece. A clever welder. however, can manage his torch so that the heat given to the two edges is proportional to their thickness; but if the differ- ence is verv great, the joint is not easily obtained. 120 OXY-AOETYLEXK WP^LDING AND CTTTINO Effects of lixpansioii : — The effects of expansion often act in such manner that the edges to be poined separate and approach each other alternately. If one wishes to join two plates by auto- genous welding, and the edges have been arranged parallel, when the weld has commenced one first observes a widening of the space, at the other end of the plate. See figure 5^^ It the weld- ing is continued, the (levialii)n (|uickly stops and the opposite movement takes place, that is. the edges ap])roach, and as the weld advances they will overlap each other. See figure 54. rig. 66. FABRICATING A BOSH JACKET IN SHOPS AT DULUTH, MINN. BOILER MAKING AND SHEET METAL WORK I'Jl Fig. 52 Fig. -).■; Fig. .■)4 EXAMPLES OF EXPANSION To overcome this final overlaping, two methods may be fol- lowed : one is to separate the edges before commencing' to weld, as shown in figure 55, and the other to weld in spots about a foot apart, throughout the length of the joint. This latter method is called tacking. In the first case the initial separation should be about 1-20 of the length of the weld, and as the weld progresses the space at the far end may be allowed to close a small amount, thus con- tinue closing the space as the weld advances, at a ratio that will bring the edges together when the weld reaches the end. In starting- this job the edges will first be placed parallel until a few inches are welded and then they will be sprung oi)cn, as sug- gested. Fig. 55 METHOD OP OVERCOMING EFFECTS OF EXPANSION, WHILE WELDING PARALLEL EDGES 122 OXV-ACKTYLEXK WELDING AND CT^TTIXG If the system of tacking is used, the expansion cannot act laterally, as in the previous case, and this causes a deformation as shown in figure ^(i. In the majority of cases, it is easy to !)'ring the plates hack to the original ])osition. Fij .")() I )i: FORM ATI ON CArHKI) BY KXI'ANSlON WHKN TIIK JOINT HAS BEKN i'HI-:VTOrsLV TACKKD 'flic Freparalion of Joints: — Welding very thin pieces, is especially difficult on account of the great liahility of melting holes through the material. In thi> kind of work, the method of overlapping the edges as shown in figure 57 is very faulty. The best method l)eing to bend the edges up as shown in figure 5S. These u])turned edges are melted down and furnish welding material. If the plates are thick enough to permit hexeling tlie\- may be prepared as in iigures so and ()0. This i> explained f|uite thoroughly under "( ieneral Notes on Welding." In Joining ])lates at right angles, the groove for welding is obtained without beveling, b\' sim])ly arranging as shown in figure 62. The joint in figure 61, which is not beveled at all. is bad when the plates are over ^ of an inch thick, because the amount of penetration is doubtful. The arrangement shown in figure 63 is favorable from the view point of penetration, but the weld is difficidt to make and in figure 04 the diiTercnce in thickness between the beveled side and the unbeveled side, makes the joli difficult for the reason that the heavy ])art re(|uires more heat than the other; but the joint can be successfully made by skillfid manipulation. BOILKR MAKING AND SHEET METAL WORK 1: Ely. .-,7 /' f Fill. 5;» Fii:. (id Vv' (il Fiu. cleaned, blow all the loose particles t)Ul with com- pressed air. Cleaning- cvlinders in this way does not heat them to a-^ high a temperature as tlie\- attain in service. CARBON Bl'K'NKIv' .XT WO UK 12.S OXY-ACETYLEXE WELDIXG AXD CUTTING x; Total Cost of cut per foot $0.0126 0.0213 0.0322 0.041 o o X Amount @ 40c per hour $0.0026 0.0033 0.0042 0.005 Time per foot in seconds -r c 00 ic cj cc re -^ji Total cost of gases .$0.01 0.018 0.028 0.036 X Oi x =H O -u CO O O < CI CI r^t L- c; C' c; c o c; o c o d c c: Oxygen @ 2c per ft. $0.0082 0.0154 0.0244 0.0306 Thickness of plate in inches '^ " -, ^' Total Cost of Weld per foot Ttl l^ L- Ol -^ o ■-;-*«> CI o =(- X O Amount (S) 40c per hour CJ «o CJ »o O CC o O O i-H >-^ CI -=&"■■■ Time per foot in minutes .3.33 8.57 15. 20. 30. Total cost of gases CC rH CI c. ISOO Lbs 109.85 329 5 1973 106 05 318 2 1909 102 3 306 S 1841 98 48 295 5 1773 95 7 284 1 1705 90 91 272 7 1636 87.12 261 4 1568 85.23 255 7 1534 83 33 250 1500 130 USEFUL INFORMATION TABLE XIV COMPARISON OF DEGREES CENTIGRADE AND FAHRENHEIT. -Below Zero. Above Zero. Above Zero Equivalents. C F C F C F C F 200 — 328 525 - 977 1250 — 2282 1—18 150 — 238 550 — 1022 1275 — 2327 2 — 3.6 100 — 148 575 — 1067 1300 — 2372 3 — 5.4 50 — 58 600 - 1112 1325 — 2417 4—72 625 — 1157 650 — 1202 1350 — 2462 1375 — 2507 5 — 9 6 — 10 S Above Zero C F 675 — 1247 1400 — 2552 7 — 12 6 — 32 700 — 1292 1425 — 2597 8 — 14 4 25 — 77 725 — 1337 1450 — 2642 9 — 16 2 50 - 122 750 — 1382 1475 - 2687 10 — 18 75 — 167 775 — 1427 loOQ — 2732 11 - 19 S 100 — 212 800 — 1472 1525 — 2777 12 - 21 6 125 — 257 825 — 1517 1.550 — 2822 13 - 23 4 150 — 302 850 - 1562 , 1575 — 2867 14 — 25.2 175 — 347 875 — 1627 ! 1600 — 2912 15 — 27.0 200 — 392 900 — 1652 1 1625 - - 2957 16 - 28 8 225 — 437 925 — 1697 1650 — 3002 17-30 6 250 - 482 950 — 1742 i 1675 — 3047 IS - .32 4 275 -- 527 1000 - 1832 1700 ~ 3092 19 !— 34 2 300 — .572 1025 — 1877 1725 — 3137 20 - 36 325 — 617 1050 — 1922 1750 — 3182 21 - 37,8 350 — 662 1075 — 1967 1775 — 3227 22 - 39.6 375 - 707 1100 — 2012 1800 - 3272 J3 — 41 4 400 — 752 1125 -- 2057 1825 — 3317 24 — 43 2 425 - 797 1150 — 2102 18.50 — 3362 25 — 45 450 - 842 1175 — 2147 1875 — 3407 475 — 887 1200 — 2192 1900 — 34.52 500 — 932 1225 — 2237 2000 — 3632 TABLE X\' WEIGHT OF OXYGEN GAS DRUMS Oxygen. Capacity. Pressure Weight Low Pressure. High Pressure. HigU Pressure.. 100 cub ft. 100 cub ft. 200 cub ft. ■ 300 lbs. 1800 lbs. 1800 lbs. 150 lbs. 125 lbs. 150 lbs. USEFUL INFORMATION 131 'fa.S ^ b-Jm 05 Ch 0-5 ^ 3 >, o 1:1. 0'-ic<>cor^coroioa)'-i o o o o o -- ■>) ^'s 00 -H X M rc -M -^ £■ '~ -r >:<— -M r- r- rr -t _ ;^ If^ lO M^ CO X f. ^. -^ O K x 02 CO o o I— I E-i % OQ o o ^ ^ „ rt ^ ^1 ~) '.0 -^ -r C2 (M — ' (M ^■^ •* 'O to t^ X w5 o ^ OJ 132 INDEX Atomic theory 13 Atomic weights 12 Acetylene 23 Alloys -...- 41 Alloys — table of _ 42 Aluminum 43 Acetylene generators 44 Assembling cutting torch 56 Automatic Oxygen regulator 59 Acetylene Regulator 58 Acetylene — oxygen required to consume 50 Acetylene in drums 81 Acetone 8 1 Adjusting the flame 95 Aluminum welding 105 Air — oxygen from 19 B Building in gear teeth 4 Boyles Law 25 British thermal unit 31 Blister Process 39 Brass 40 Brass— welding 1 04 Building a furnace 76 Beveling 89 B ronze — welding 1 04 Boiler making 1 18 Calcium Carbide 21 Calorie 3 1 Centigrade 32 Coefficients of expansion 33 Calculations in expansion 33 Conductivity of heat 34 Cast iron 35 Cast iron welding IQl Cast iron flux 88 Copper 39 Copper flux 88 Copper welding 104 Carbide 21 Carbide to water generator 45 Carbide — yield of gas Composition of sludge 72 Cost of acetylene 69 Clean oxygen hose 80 Cleaning the weld 89 Charges for welding service 84 Chloride of potash method of pro- ducing oxygen 18 Cutting torch 53 Cutting iron and steel 110 Cutting steel floor beams 115 Cutting machines 1 13 Cost of gas for cutting 114 Carbon burning 126 Comparative cost of cutting 7 Chemistry 1 1 Origin I I Elements 1 1 Symbols 1 1 Atomic weights 12 Notation 12 Affinity 1 3 Atomic theory 13 Valence 14 Re-action 16 Combustion 16 Flame 1 6 Drip type generator 45 Dissolved acetylene 81 Defects of welds 100 Directions for carbon burning ...126 Drums of acetylene 81 Examples of savings 4 Elements 1 1 Electrolysis 1 9 Effect of temperature on pressure 28 Expansion 32 INDEX 133 Expansion — coefficients of 33 Expansion — calculating the 33 Expansion — precautions regarding... 91 Expansion — effects of 92-120-121 Economy of preheating 94 Examples in welding 107 Flame 16 Fahrenheit 3 1 Ferrous group of metals 35 Flashing Back 50-80 Fluxes 87 For cast iron 88 For copper 88 Filling in holes 99 Fabricating a bosh jacket 119 Oxygen 17 Hydrogen 20 Nitrogen 21 Acetylene 23 21 26 23 27 89 Gas — weight of Gas — quantity in drums Gas — yield from carbide Gay Lusac's Law General notes on welciing H Hydrogen 20 High pressure pump 29 Heat 30 Heat conductivity 34 Heat liberated by carbide in wa- ter 44 High pressure torch 52 How and where to preheat 95 Handling the torch 96 Holes— filling in 99 L Low pressure torch 51 Loss of pressure in pipes 70 Loss of pressure in valves and fit- tings 71 Leaks in oxygen pipes 73 Lead burning 106 Leaks — testing for 73 Lead welding 106 Liquid air — oxygen from 19 M Metals and their properties 35 Malleable cast iron 36 Malleable cast iron welding 102 Melting temperatures „ 39 Movements of the torch 98 Machine for cutting 113 Manganese dioxide method of pro- ducing oxygen 18 N Nitrogen 21 Neutral flame 95 o Oxygen 1 7 From air 19 By electrolysis 19 From chloride of potash and manganese-dioxide 18 Oxyacetylene cutting 6 Oxyacelylene torch 50 Oxygen required to consume acety- lene 5 Operating plants 68 P Phases of combustion 1 7 Physics 25 Phneumatics 25 Pressure regulators 58 134 INDEX P Preheating furnaces 76 Protecting apparatus _ 77 Portable acetylene drum plant 81 Portable acetylene generator plant 83 Preheating to eliminate defects 94 Preheating how and where 95 Puddle-system ' 05 Preparing the joint 1 .^-^ Propagation of flame 5U R Repairing locomotive cylinder 2-3 Repairing pump case 10 Reaction 1 s Steel 38 Steel welding 101 Selecting a generator 47 Sludge — composition of 72 Scrapping a boiler iio T Time required to cut plates 7 Temperature 3 1 Thermometers 3 1 Temperature of melting 39 Thermite 43 Typical carbide to water genera- tor 45 Torches 50 Torches — for machines 57 Testing pipe lines 73 Time card for welding shop 86 Theory of cutting 110 U Use of the oxyacelylene torch 4 Using the cutting torch Ill Unit of heat .....31 Unit — British thermal 31 V Valence 1 4 Velocity of propagation of flame 50 Vulcan automatic acetylene gene- rator 61 Vulcan portable generator plant . 67 W Welding crank shaft 8-107 Weight of gases 21 Wrought iron 37 Welding — Iron and steel lOl Cast iron 101 Malleable cast iron 102 Copper 1 04 Brass 1 04 Bronze 104 Aluminum 1 05 Lead 106 Welding rods and fluxes 87 Welding table 74 Welding — examples in 107 Auto cylinders 108 Auto springs 1 09 Crack in boiler 124 Patch in boiler 124 Flues in boiler 125 Welciing pieces of different thick- ness 1 19 Yield of gas from carbide 23 Pure Calcium Carbide "HPHE purity of Acetylene goes hand in hand with the purity of Carbide, and, just as preventive is better than cure, so to use only an excellent quality of Carbide, thus avoiding impurities, is clearly better than to use a poorer grade which is sure to result in the formation of impurities." —PROF. GEORGE GILBERT POND, Leading Authority on Acetylene. We thoroughly agree with Professor Pond, that only Car- bide of the Greatest Purity should be made. Therefore, we handle only the one grade — that the best it is possible to produce. Our r TRADE f "^U^^VVS^^M;^' MARK distinguishes pure from impure Carbide, and stands for a defi- nite, guaranteed gas yield. American Carbolite Sales Co. DISTRIBUTORS Warehouses Everywhere DULUTH, MINNESOTA S*^'^'^'''^'""'^''''^''''"''^'""'^'^'"^^'''"'^^ A Vulcan Welding Torch, Acety- lene Generator, or Com- plete Welding Plant is far in advance of the average Welding appa- ratus. All SPECIAL FEATURES are pro- tected by patents. Cost is lowest consistent with greatest efficiency known. VULCAN PROCESS CO. Factory and Sales Room 25 th and University Ave. S. E. MINNEAPOLIS, MINN. 1^ Pure Compressed Electrolytic Oxygen Highest Grade Vulcan Oxy - Acetylene Welding Supplies llicre arc some cheap iniilalions of N'ulcan Wcldin;; supplies. Do not accept them. If your dealer does not carrv \ulcaii supplies, send order tlirect to us, and we will make shipment same day order is received. All our weidinj; rods, includini;- the cast iron, steel, bronze, aluminum and aluminum solder, rods are made u]) alter our own f(»rmulaes. and have been ado])led only alter years of ex])erimentini;- and testin,<;. ( )ur duxes fi>r cast iron ueldin.u-. aluminum weldin-- or brass and bronze weldini;- are extra stren,L;th and when usin.^ ibem. direc tions should he followed clt'sel). We maintain a complete j >1) repaii plant in connec- tion. NORTHERN WELDING COMPANY Manufacturers of Complete Weldin-- iM|uii)ment and Supi^Hcs 25th and University Ave. S. E. Minneapolis, Minn. |