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 COPYRIGHT DEPOSnV 
 
The Practical Enameler 
 
 WITH ESPECIAL REFERENCE TO 
 
 ENAMELING SHEET-STEEL 
 AND CAST-IRON WARE 
 
 With Useful Information Relating to All Side Lines 
 
 AN EXCEPTIONALLY COMPLETE 
 
 Manual for Self -Instruction 
 
 FOR ALL THOSE ENGAGED OR 
 INTERESTED IN THE TRADE 
 
 OTTO GRAMPP 
 
 AUTHOR and' publisher 
 New York, U. S. A. 
 
 1909 
 

 C-Ci. A 368238 
 
PREFACE 
 
 The author of this volume has assumed the 
 task of supplying the Enameling Trade with a 
 really useful and readily understood Manual, 
 treating the subject in an absolutely tip-to-date 
 manner, and availing himself of the latest 
 achievements of modern scientific progress. 
 
 As the Enameling Trade up to the present 
 time has not had any literature worth mention- 
 ing, in the English language, at least, I feel con- 
 fident that my efforts, devoted to so useful a 
 cause, will meet with general appreciation. 
 
 The Author. 
 
Table of Contents 
 
 Page 
 
 A General Review 7 
 
 Male and Female Labor 12 
 
 Danger of Injury to Employees 14 
 
 Wages and Working Hours 16 
 
 Annealing and Pickling the Crude Ware 20 
 
 The Crude Materials Entering Into the Composition of 
 Enamel Fluxes 24 
 
 The Smelting Process 55 
 
 The Grinding Process 58 
 
 The Coating and Firing Processes 62 
 
 The Coefficients of Expansion of Sheet-steel Formulas 70 
 
 Cast-iron Enameling 72 
 
 Majolica Ware Enamels 75 
 
 Enamel Painting 78 
 
 Pastel Painting on Enameled Paints 83 
 
 Pastel Crayons 85 
 
 The Application of Photo-ceramics to Enamel 87 
 
INTRODUCTION 
 
 After many years of technical work in the 
 EnameHng Trade, during which time I had oc- 
 casion to acquire an extensive and thorough 
 knowledge of the various enameling methods, I 
 have decided to embody in this volume the results 
 of my experience for the benefit of those engaged 
 and interested in the trade, giving at the same 
 time a number of reliable and practical receipts 
 for the preparation of enamels. 
 
 I have also devoted a chapter to a briefly out- 
 lined description of the technique of enamel 
 painting which may prove of interest, not only 
 from a business standpoint, but also for the 
 lovers of art. 
 
 It appeared to me advisable to refrain, as much 
 as possible, from the use of scientific or technical 
 terms, thereby presenting to my readers a lucid, 
 readily comprehensible review of the subject 
 matter. 
 
 I therefore cherish the hope that the volume 
 I herewith submit to them may prove a reliable, 
 useful and profitable guide for all who are inter- 
 ested in this branch of industry and art. 
 
 New York, 1909. Otto Grampp. 
 
A General Review 
 
 Enameling is numbered among the very an- 
 cient arts, the Egyptians, Greeks and Etruscans 
 having been exceedingly skilful in the produc- 
 tion of enameled articles. 
 
 In the loth century, Theophilus, a monk, wrote 
 a detailed description of the preparation of 
 enamel. 
 
 Subsequently, in the latter part of the Middle 
 Ages, the Italians were the first to produce trans- 
 parent enamels which enabled the French to 
 evolve the art of enamel painting, a discovery 
 which was chiefly utilized on a trade basis in the 
 French city of Limoges. 
 
 The civilized nations of Eastern Asia were 
 also at an early date conversant with the enamel- 
 ing art. 
 
 However, as enameled articles in those times 
 were exceedingly valuable, in view of the ex- 
 pensive method of production, they could only 
 be purchased by the wealthy, who acquired them 
 as a luxury, the making of enameled articles on 
 
a large scale consequently being wholly out of 
 the question. 
 
 The first production of enameled ware for 
 practical purposes does not date back further than 
 the 19th century, previous to which time clay, 
 stone, woodenware, etc., were found in every 
 household. As vessels of this description were 
 not, however, available for all purposes, it soon 
 became necessary to provide such as could be 
 readily cleaned and used for every purpose, 
 while being at the same time proof against all 
 chemical action, and free from any qualities 
 which might make them injurious to health. A 
 further important requirement was cheapness, 
 bringing these utensils within the reach of the 
 poor. 
 
 The enormous technical progress which marked 
 the latter half of the i8th century made it pos- 
 sible to produce vessels complying with the afore- 
 said requirements. These utensils were, in fact, 
 the forerunners of modern enameled sheet-iron 
 ware which, however, was not produced on a 
 manufacturing scale until Enameling Works 
 were established in Germany in the early fifties 
 of the last century. During the past 25 years 
 the development of this new branch of industry, 
 which has wholly superseded the old art enamel, 
 
 8 
 
has been rapid, until it has reached its present 
 importance. The production of enamel cooking- 
 utensils, therefore, cannot be considered a new 
 invention, but only an improved application of a 
 process known long ago. 
 
 Like all innovations, enameled ware was at 
 first received with many misgivings. These uten- 
 sils were looked upon with distrust, and they 
 were not thought to be durable, because they were 
 too light in weight. They were also considered 
 injurious to health. 
 
 The medical fraternity spread reports in which 
 the assertion was made that the accidental swal- 
 lowing of enamel chips was frequently the cause 
 of inflammation of the blind gut. After having 
 been denied by various authorities, this conten- 
 tion was recently again disproven by professors 
 on the medical staff of one of the largest and 
 best-known hospitals of Hamburg (Germany). 
 I shall have occasion to note their opinion in one 
 of the following chapters of this volume. 
 
 In view of this opposition it was at first a 
 rather difficult matter to find a market for enam- 
 eled ware, until the public began to gradually rec- 
 ognize the many advantages afforded by these 
 utensils, whose popularity increased until at the 
 present time it would be a difficult matter to find 
 
a household not equipped with an assortment of 
 enameled sheet-iron ware. 
 
 In addition to enameled sheet-iron ware, enam- 
 eled cast-iron kitchen utensils, etc., w^ere placed 
 upon the market and bought principally by people 
 who feared that their health might be impaired 
 by the use of enameled tinware. These cast-iron 
 utensils, however, are only rarely met with at 
 present, as they have almost completely made way 
 for the light, convenient enameled sheet-steel 
 ware. 
 
 The following figiu*es will give an idea of the 
 rapid development of the enameling industry: A 
 certain manufacturing concern employed 260 
 hands in 1872, 453 in 1881, 788 in 1884, 1,300 in 
 1887, 1,832 in 1890 and 3,600 hands in 1900. 
 
 Various reasons make it impossible to give a 
 detailed and accurate review of the labor condi- 
 tions prevailing in the enameled sheet-steel ware 
 industry considered as a whole. 
 
 The very great diilerence in the assortments 
 made, and in the technical installation and ar- 
 rangement of the various plants, precludes the 
 possibility of finding even two shops in which 
 the hands are worked under the same system. 
 
 Comparisons between the various manufactur- 
 ing plants in regard to the wage scale, living ex- 
 
 10 
 
penses and rents are likewise impracticable, in 
 view of the fact that these figures are largely 
 determined by local conditions, while the manu- 
 facturing plants are distributed over a number 
 of different countries. 
 
 The personal views of manufacturers re- 
 garding the required number of working hours, 
 the manner in which the work should be divided 
 and other important questions are, moreover, 
 so widely divergent that any attempt to obtain 
 uniformity regarding these matters would result 
 in absolute failure. 
 
 The one feature common to all enameling 
 plants is a system by which the work is most 
 thoroughly specialized or divided among the 
 hands, this being, in fact, the only means by 
 which manufacturers can produce an enormous 
 output of enameled ware with a limited number 
 of hands. 
 
 11 
 
Male and Female Labor 
 
 Enameling Works employ both men and 
 women, the work being divided among them 
 according to the judgment of the management. 
 As a general rule, how^ever, I may state that men 
 only are employed for making the enamel com- 
 position and the packing cases, and that the 
 machinery is also exclusively operated by men. 
 
 Both men and women work in the pickling 
 rooms, where the women are more especially em- 
 ployed for scrubbing the goods, as well as in the 
 enameling shop and in the stockrooms. 
 
 The coating of the utensils with enamel com- 
 position, the rimming, drying and annealing, as 
 well as the sorting of the various grades and the 
 packing of the goods, are done by both men and 
 women. 
 
 Women are particularly well adapted for light 
 work requiring a certain deftness and skill with 
 the fingers, while men are, of course, better 
 equipped for all kinds of work requiring physical 
 strength. Experience, furthermore, has proven 
 
 12 
 
that it is more advisable to employ men than 
 women for all such work as might prove danger- 
 ous to a careless person. This applies more 
 especially to the stamping work. 
 
 13 
 
Danger of Injury to 
 Employees 
 
 There being, as a rule, only very slight danger 
 of injury to persons employed in enameling 
 works, the number of accidents is by no means 
 large. The stamping shop is, in fact, the only 
 one in which very careless hands can suffer seri- 
 ous injury, although the dies move so slowly that 
 accidents are infrequent. Moreover, the danger 
 of having their fingers pinched off is so apparent, 
 and is so constantly before the workmen, that it 
 makes them doubly careful. 
 
 In an attempt to make the operating of stamp- 
 ing machinery absolutely free from danger, one 
 of the largest works in Germany has offered to 
 pay a considerable sum of money to any one in- 
 venting a safety device which would make it im- 
 possible for the fingers or hands of the operator 
 to be caught in the machine. The problem, how- 
 ever, has not as yet been solved. 
 
 The only work which might in course of time 
 
 14 
 
prove injurious to the health of the employees is 
 the mixing of the enamel compositions. The 
 men should, therefore, never neglect to use the 
 safety device which protects them from inhaling 
 through their mouths and nostrils the dust pro- 
 duced during the mixing process. 
 
 15 
 
Wages and Working Hours 
 
 The various Enameling Works pay their hands 
 either by the hour, for individual piece work, or 
 for piece work by gangs or crews. 
 
 Hands operating power machinery are always 
 paid by the hour. All work in which accuracy 
 and a perfect product are of greater importance 
 than speed should, moreover, also be paid for per 
 hour. This applies more especially to the mixing 
 of the enamel compositions. In some shops the 
 firing and annealing are paid for by the hour, and 
 in others by the piece. The wages for all me- 
 chanical work, such as stamping, spinning, cut- 
 ting, folding, packing, etc., are exclusively fig- 
 ured on a piece-work basis, the wage scale for 
 such piece-work being, of course, determined by 
 the management of the individual shops. 
 
 Although manufacturers hold widely divergent 
 opinions regarding the advantages or disadvan- 
 tages of the piece-work system, it is an incontro- 
 vertible fact that it greatly facilitates supervision 
 in the shops. 
 
 16 
 
In order to ascertain the relative influence of 
 improvements introduced in the installation of 
 new manufacturing plants, or of modifications in 
 the machinery of existing plants, the old wage 
 scale for piece-work should be maintained for 
 some time, when the increase in the earnings of 
 the individual hands will show to what extent the 
 output has been increased by such improvements 
 or modifications. 
 
 In case an invention made by one of the hands 
 proves a success, the inventor should receive an 
 adequate reward, inasmuch as the chance of being 
 thus remunerated will induce many of the men to 
 acquire a more thorough knowledge of the ma- 
 chines they operate, thereby possibly discovering 
 chances of practical improvements which cannot 
 fail to prove profitable to their employer. 
 
 Ten hours constitute the average working day 
 in Enameling Works. The men in charge of fir- 
 ing the goods frequently work in eight-hour 
 shifts, in order to utilize to better advantage the 
 furnaces in which the fire must, of course, be 
 constantly kept up, whether they are being used 
 or not. 
 
 In consequence of the dififerent operating sys- 
 tems it would be impossible to establish any gen- 
 
 17 
 
eral rule ii^oveniing the number and division of 
 the working hours in EnanieHng- Works. 
 
 In view of the fact that the consumption of 
 enameled cooking- utensils has constantly in- 
 creased din"ing' the last ijuarter of a century, and 
 that many new markets have been opened up. 
 with the result that the annual output has at- 
 tained enormous proportions, it is indeed surpris- 
 ing that the nimiber of Enameling Works in the 
 United States, pre-eminently a land of progress. 
 has remained extremely limited, a fact which is 
 all the more inexplicable because a large percent- 
 age of her annual consumption of enameled ware 
 is imported from Germany and Austria, although 
 the import duty on enameled cooking utensils is 
 40 per cent, ad \'alorem, figured on the value of 
 the giHuls ill the country of origin. 
 
 In 1904 the number of Enameling Works es- 
 tablished in Germany was seventy-one, with a 
 total working capital of from 50,000,000 to 
 LXD,ooo.ooo marks, and employing about 22,000 
 hands. The annual sales of some of these works 
 range between 8,000,000 and 0,000.000 marks. 
 
 These figures demonstrate that the manufac- 
 ture of enameled ware has become an exceed- 
 ingiv important factor in industrial economics, 
 and that only unceasing etYort. continual progress 
 
 IS 
 
and inipro\'ed, up-to-date operating methods can 
 insure an adequate development of this industry 
 in our country, and place it in a position to suc- 
 cessfully meet the competition of foreign goods. 
 
 19 
 
Annealing and Pickling the 
 Crude Ware 
 
 The proper preparation ot" the crude ware he- 
 tore it goes to tlie enameling rooms is one of the 
 most important l"eatures of the enameHng proc- 
 ess, and should accordingly receive most careful 
 attention. 
 
 We shall tirst {proceed to consider the anneal- 
 ing process. The nuil'tle furnace used iov anneal- 
 ing should he kept at a constam heat oi ahiuU 
 800 degrees V.. as the product would sulYer to the 
 same extent either hv heing alUnved to remain 
 too long in an underheated furnace, or hv heing 
 annealed t(X^ rapidly hy exposure to excessive 
 heat. 
 
 In order to insure perfect annealing, the crude 
 ware, before being charged into the annealing 
 furnace, is lirst dipped in a weak mixture of 
 water and muriatic acid, for the purpose of hav- 
 ing all grease and impurities adhering to the 
 ware (in consequence o\ its having passed 
 
 20 
 
througli tlic stainiHiig- ])rcsscs and i)lanisliing' 
 machines) c(>iiij)lctcly consumed durinj^ Uic 
 annealing- process. 
 
 Tlie crude ware should not under any circunr 
 stances he jjiled uj) too hij^Ii, or nested in the an 
 neahng furnace, and unless strict attention is paid 
 to liiis re(|uirenient, the surfaces will not come in 
 contact with a sufficient volume of oxyj^en, and 
 the oxidation will conscciuently he uneven, a 
 defect which results in the formation oi un- 
 sightly hlisters, and therefore increases io a 
 very considerahle extent the percentage of sec- 
 onds and waste. 
 
 After the crude ware has heen prepared as 
 ahove descrihed it is removed to the pickling 
 room. The pickle, which may he composed either 
 of 90 parts water and 10 parts C(;ncentrated sul- 
 phuric acid of 65' Ik', or of one part muriatic 
 acid and two parts water, must be mixed in vats 
 especially made for that purpose of pitch pine, 4" 
 thick, with groove and tongue joints, and 
 thoroughly coated with tar on the outside. 
 
 Muriatic acid pickling liquors are preferable 
 to thr>se made with sulphuric acid; first, because 
 they are cheaper, and, secondly, because they irri- 
 tate the lungs of the workmen to a lesser extent. 
 The weight of the pickle in each vat should be 
 
 21 
 
ascertained daily, this being an operation which 
 an intelHgent workman can easily accomplish in 
 a few minutes. 
 
 After immersing the crude ware in the pickle, 
 and leaving it in the same until sufficiently 
 pickled, a process to which any wcM^kman can at- 
 tend after a short training, it is taken out and 
 placed in a vat of pure water, in which it is left 
 for an hour at least, to make sure that all of the 
 acid has been washed off. The crude ware is 
 then scoured with sand and boiled for a few min- 
 utes in weak soda lye. After having been boiled 
 it is dried and immedialely conveyed to the 
 enameling room. 
 
 It is not advisable to allow pickled crude ware 
 to stand overnight, and all the goods should, in 
 fact, be coated with enamel on the same day they 
 are pickled. 
 
 When the pickling vats have been used for a 
 short time, a nuiddy mass composed of precipi- 
 tated oxide of iron and iron scale is deposited on 
 the bottom. This deposit must at certain inter- 
 vals be removed from the vats. For this purpose 
 the clear acid solution is drawn off into clean old 
 barrels, the bottom o\ the vats is cleaned, the 
 acid which has boon drawn off poured back, and 
 fresh water and pure acid added, uiuil the acid 
 
bath has recovered its standard strength. The 
 old acid soUition must always be used again, not 
 only because it means a very considerable sav- 
 ing, but also because a bath made without acid 
 that has previously been used acts very slowly 
 and imparts a bluish-gray color to the pickled 
 ware. 
 
 Before coating the goods with enamel, they 
 must be examined to ascertain whether the folded 
 seams are tight, and whether the ware has been 
 closely riveted. This inspection can be made by 
 the same workman charged with removing the 
 dents from the utensils. If the folded seams and 
 the rivets are not tight, and also when the rims 
 are poorly bordered, blisters will form, and it be- 
 comes consequently impossible to produce neatly 
 finished and perfect ware. 
 
 The various defects found in finished enameled 
 ware will be discussed in one of the following 
 chapters. 
 
 23 
 
The Crude Materials Enter- 
 ing Into the Composition 
 of Enamel Fluxes 
 
 BORAX. 
 
 Borax (Na2 B4 O? + 10 H2 O), known in chem- 
 istry as Sodium Borate, is readily soluble in hot 
 water. It melts at red heat and loses 47% of 
 crystallization water in the melting process. This 
 salt is used in all Enameling Works as the most 
 effective flux, best adapted for this special pur- 
 pose. During the melting down of the Enamel, 
 Borax shows a peculiar action, inasmuch as it at 
 once and directly induces the formation of the 
 ground-mass. 
 
 Natural Borax is found on the coast of Cali- 
 fornia and in other localities, but it is likewise 
 obtained by neutralizing boracic acid (HsBO.O 
 with sodium carbonate. 
 
 Manufacturers will find it to their advantage 
 
 24 
 
to calcine and melt a small sample of each ship- 
 ment of Borax they receive, as this will enable 
 them to ascertain at once whether the Borax con- 
 tains any oxide that would color the Enamel. 
 When smelted, pure Borax should present the 
 appearance of pure crystal glass, while a green 
 coloring indicates the presence of copper, a red 
 coloring the presence of peroxide of iron (Fe2 Os) 
 and a purple coloring the presence of manganese 
 compounds. 
 
 Borax should always be bought either ground 
 fine, or in the form of very small crystals, be- 
 cause it will mix better with the other component 
 parts of the Enamel and fuse more perfectly with 
 the same, thereby producing a finer and more 
 uniform glazing. 
 
 When heated in the blowpipe flame Borax un- 
 dergoes the same changes as boracic acid. At 
 first the mass bubbles up violently, and thereupon 
 quickly melts down until it assumes the appear- 
 ance of a glass bead. If powdered Borax is 
 mixed with metal oxide and the mixture smelted, 
 the oxide will dissolve completely in the Borax. 
 When mixed w4th the oxides of iron and anti- 
 mony (H2O3) the bead will be yellowish red, 
 while an admixture of cupric (Cu O) or chromic 
 oxide (Cr- O3) will produce a red, cobaltic oxide 
 
 25 
 
(C02O3) a blue, and manganese dioxide (Mn 
 O:.') and oxide of manganese (MnsO*) a brown 
 bead. 
 
 Borax should always be stored in an absolutely 
 dry place, because it is strongly hygroscopic (i. e., 
 it absorbs the moisture from the air) and will 
 consequently contain a large additional amount 
 of water of crystallization after having been 
 stored in a humid place, a circumstance which 
 may in some cases prove a serious disadvantage 
 in the preparation of enamel fluxes. 
 
 A mixture of boracic acid and soda (made by 
 the ammonium process) in the chemically correct 
 proportions may be used instead of Borax. 
 
 Borax and boracic acid are used in the prepara- 
 tion of glazing for earthenware and fine crockery 
 in a similar manner as in the enameling industry, 
 for glass and china, and of optical glasses. The 
 use of Borax for welding metals, soldering (so 
 called "Jewelers' Borax"), etc., is undoubtedly 
 known to my readers. The welding of cast steel, 
 for instance, was for a long time considered im- 
 possible, until it was finally discovered that it 
 could be welded by using a flux containing a com- 
 paratively large percentage of boracic acid or 
 Borax. The composition known as "Kohler's 
 Cast Steel Flux" contains 8 parts Borax, 7 parts 
 
 26 
 
sal ammoniac, lo parts ferrocyanide of potas- 
 sium (prussiate of potash) and 5 parts rosin. 
 
 Borax is also used for making finishing com- 
 pounds for white fabrics, and for manufacturing 
 gloss starch, stearine candles, colors, etc. 
 
 FELDSPAR. 
 
 Feldspar (K2 Ah Sic Oie and Na2 Ah S'u 
 Oio), one of the most important ingredients of en- 
 amel fluxes, is found in many different parts of 
 the United States. When purchasing a supply 
 of Feldspar, the manufacturer should, above all, 
 try to obtain a pure white article, the smelting 
 test being the simplest means of ascertaining 
 whether it answers this requirement. 
 
 When smelting pure, unmixed Feldspar, a 
 transparent, distinctly crystalline mass of consid- 
 erable hardness is obtained. 
 
 The greater the purity of the Feldspar used, 
 the purer will be the enamel. 
 
 Manufacturers producing exclusively fine 
 white enameled ware should buy their Feldspar 
 in lumps and grind it in their own mills, this be- 
 ing practically the only way in which they can 
 be sure of always obtaining pure material, free 
 from any foreign admixtures. 
 
 Some manufacturers import their supplies of 
 
 27 
 
Feldspar from Norway, which country produces 
 the grade of Spar best adapted for making pure 
 white enamel. The Norwegian article, however, 
 may safely be replaced with the domestic product, 
 as long as a pure white grade is obtainable. 
 
 The answer to the question whether it is more 
 advantageous to use Sodium Feldspar or Potas- 
 sium Feldspar depends on the composition of the 
 Enamel fluxes for which the material is to be 
 used. 
 
 QUARTZ. 
 
 Quartz (Si O2) is a mineral of considerable 
 importance both in enamel manufactiu'ing and in 
 glassmaking. Either quartz or finely ground 
 quartz sand or flint may be used, since all of 
 these materials are chemically pure silex. If 
 pure white quartz is obtainable, it should be used 
 by preference for fine white Enamel, the price 
 being, of course, generally too high to allow of 
 the use of this material for all grades of Enamel, 
 and more especially for colored enamels and glass 
 fluxes. 
 
 Quartz sand, deposited on the banks of large 
 rivers, consists generally of Quartz rock, disin- 
 tegrated by the powerful action of water, and it 
 may be used as an excellent material for making 
 Enamels and glass fluxes. 
 
 28 
 
FLUORSPAR. 
 
 Fluorspar (Ca F2) is a natural product, found 
 in the form of beautiful crystals, or as a solid 
 mass. In some places it occurs in an absolutely 
 pure state, but colored Fluorspar in various 
 shades is likewise found in many localities. 
 
 Only absolutely colorless Fluorspar is available 
 for Enamel manufacturing. It renders the En- 
 amel more fluid, but great care must be used in 
 employing Fluorspar as an admixture to Enamel, 
 and more especially with Enamels used for the 
 ground coat, the excess of lime having a detri- 
 mental effect on their quality. 
 
 SODA. 
 
 Calcined Soda (Soda Ash, Na- COs) is the 
 only kind used in Enameling Works, since the 
 water contained in soda crystals is useless to the 
 manufacturers and only increases the cost of 
 transportation. 
 
 An admixture of Soda and Potash in the right 
 proportions gives Enamel a more brilliant gloss, 
 while an excess of Soda makes it dull. Soda Ash 
 contains 41% carbonic acid and 59% sodium. As 
 common commercial Soda Ash generally contains 
 considerable iron, which has. a very detrimental 
 
 29 
 
effect on fine white enamel, and gives it a yellow- 
 ish tint, the Soda manufactiu-ers have placed a 
 special grade on the market, known as "Enamel- 
 ing Soda," which is absolutely free from iron, but 
 necessarily higher in price than the common 
 article, for which reason it is. of course, used 
 exclusively for fine white Enamels. 
 
 Like Borax, Soda Ash must be stored in an 
 absolutely dry place, for it will otherwise absorb 
 moisture from the surrounding air and become 
 caked into lumps as hard as rock. 
 
 CRYOLITE. 
 
 Cryolite (Noo AI2 Fil>) is a liux and further- 
 more possesses in a very high degree the quality 
 of making Enamel opaque. It occurs in nature 
 in beautiful milky white pieces, greasy or oily 
 to the touch, which can be easily scratched with 
 the finger nails. It should be bought only in 
 pieces, and manufacturers should not object to 
 the trouble of grinding it, because they can only 
 be sure of using an unadulterated material if 
 they purchase it before it is ground. 
 
 A new product, known as Artificial Cryolite, 
 has recently been placed upon the market. It is 
 a by-product obtained from the manufacture of 
 artificial fertilizers, but it generally contains a 
 
 30 
 
large percentage of silex and causes manufac- 
 turers a great deal of trouble because it prevents 
 them from making their Enamel opaque, while 
 likewise impairing its fusibility. 
 
 OXIDE OF TIN. 
 
 Manufacturers have long been trying to dis- 
 cover a substitute for the exceedingly expensive 
 Oxide of Tin (stannic oxide, Sn O2) used in the 
 preparation of Enamel. Many experiments have 
 been made and some alleged substitutes were, in 
 fact, placed upon the market, but as the results 
 obtained with them were by no means satisfac- 
 tory, consumers were compelled to return, al- 
 though unwillingly, to the use of Tin Oxide. 
 
 It is true that Oxide of Tin may partly be re- 
 placed with White Oxide of Antimony, but the 
 use of this latter product is likely to expose man- 
 ufacturers to serious annoyances, inasmuch as 
 the allegation might be made that their cooking- 
 utensils are injurious to health, certain parties 
 having claimed that inflammations of the blind 
 gut are in a majority of cases due to the presence 
 of poisonous enamel chips. 
 
 It would, of course, be an exceedingly difficult 
 matter for any one to prove this contention in the 
 courts. I do not believe, in fact, that any one 
 
 31 
 
engaged in the trade would refuse to perma- 
 nently eat food cooked in utensils coated with 
 Enamel containing antimony, inasmuch as the 
 amount of antimony used is too small to have 
 any injurious effect on the consumer's health. 
 
 In this connection I consider it opportune to 
 print below an expert opinion, issued by C. Sick, 
 M. D., Physician in Chief of the 2d Surgical De- 
 partment of the General Hospital ("Allgemeines 
 Krankenhaus") of Hamburg-Eppendorf. 
 
 Th;s authority writes: 
 
 "The number of foreign substances found in 
 the human intestinal tract is legion, and any of 
 these substances may enter the vermiform appen- 
 dix with the fecal matter when not too large. 
 The fact, however, that such foreign substances 
 are but rarely found in the appendix, suggests 
 the possibility that the presence of a foreign 
 substance will only cause morbid conditions when 
 it either remains a long time in the appendix, or 
 causes inflammations or lesions. Foreign sub- 
 stances in the intestines are, however, invariably 
 enveloped in fecal matter, and thus conveyed in a 
 manner favorable to their excretion from the in- 
 testinal canal. Investigations prove that even 
 substances which, in view of their shape or form, 
 might easily cause damage, such as fish bones, 
 
 32 
 
needles and pins, pass rapidly through the in- 
 testinal tract without causing any injury, be- 
 cause the fecal matter which surrounds them 
 makes them harmless. 
 
 "In their attempt to discover the causes of ap- 
 pendicitis, men of professional ability and mere 
 meddlers have based their arguments on a great 
 variety of theories which might possibly explain 
 these causes. Among these attempts to explain 
 the origin of the disease is the theory that ap- 
 pendicitis is due to enamel chips from kitchen 
 utensils, which find their way into the intestines 
 and cause inflammation. 
 
 "A perusal of the literature on the subject, 
 which has assumed appalling proportions, shows, 
 however, that no one ever really discovered an 
 enamel chip in the vermiform appendix. And even 
 though such a chip should actually be found in 
 the appendix, such a discovery would still be de- 
 void of all value as evidence, inasmuch as an 
 enamel chip might just as easily be carried into 
 the appendix, as fecal matter and other foreign 
 substances have occasionally found their way 
 there. 
 
 "That the presence of an enamel chip in the 
 vermiform appendix must be an exceedingly rare 
 occurrence is proven by the fact that none have 
 
 33 
 
ever been found (see Prof. Sprengel's opinion), 
 as there is just as much chance of finding such 
 a chip as of occasionally finding needles, fig- 
 seeds or shot, all of which have been discovered 
 in the appendix. It would first be necessary to 
 prove that the presence of enamel chips in cases 
 of appendicitis is a very frequent occurrence, and 
 that there is any connection between their pres- 
 ence and the morbid condition of the vermiform 
 appendix, before it could be asserted that enamel 
 chips are one of the causes of inflammation of 
 the blind gut (caecum). 
 
 "I have made investigations in Hamburg in 
 both of the large General Hospitals, for the pur- 
 pose of ascertaining whether an enamel chip had 
 ever been found in the vermiform appendix in 
 cases of appendicitis, or in any autopsy. The 
 result proved that such had never been the case. 
 In the General Hospital of Eppendorf I myself, 
 with Dr. Kuemmell, removed the diseased vermi- 
 form appendix by operation in more than i,6oo 
 cases, without ever finding an enamel chip, not- 
 withstanding our thorough examination. To 
 this evidence should be added the numerous cases 
 in which the same operation was performed in 
 private practice, in which the search for such 
 chips also produced negative results. According 
 
 34 
 
to the report of Dr. Weininger, Surgeon in Chief 
 of the St. George General Hospital, foreign sub- 
 stances have been sought in all such operations. 
 They were, however, discovered only rarely, 
 those found being, for instance, pins, shot, apple 
 and fig seeds, hairs from tooth brushes and in- 
 testinal worms (Oxyures), but particles of tin 
 from cans containing preserved food, as well as 
 enamel chips, were never discovered in any of 
 the cases. 
 
 "Dr. Fraenkel and Dr. Simmones, Assistant 
 Professors of Anatomy at the Anatomical Insti- 
 tutes of the two General Hospitals, assured me 
 in reply to an inquiry, that they had never found 
 an enamel chip either in a case of appendicitis or 
 in a sound vermiform appendix. 
 
 "The foregoing facts, which are wholly in ac- 
 cord with the findings of other investigators, lead 
 to the conclusion that enamel chips have never 
 been found in the vermiform appendix, and that 
 they can consequently not be considered as the 
 cause of any case of appendicitis. 
 
 "The opinion that morbid conditions of the 
 vermiform appendix are due to the presence of 
 enamel chips from cooking utensils, which, un- 
 fortunately, prevails quite generally, is based 
 merely on a senseless repetition of a wholly un- 
 
 35 
 
proven assertion which is unwarrantedly gaining 
 wider circulation. 
 
 ''I am well aware, both from personal experi- 
 ence and the statements of others, that cooked 
 food sometimes contains enamel chips in the form 
 of minute particles, scaled oft" from the cooking 
 utensils, it being a well-known fact that this oc- 
 casionally happens. These minute enamel chips, 
 however, have as yet never been found in the in- 
 testinal tract, or, more especially, in the vermi- 
 form appendix, and no injury to health, or, to be 
 more precise, no inflammation of the caecum 
 (blind gut) was ever found to be attributable to 
 the action of such enamel chips. 
 
 "These enamel chips are heavy and will gener- 
 ally fall to the bottom of the cooking utensils. 
 If they enter the mouth with the food their pres- 
 ence is readily discovered by the exceedingly high 
 development of the sense of touch, because they 
 are of irregular shape. They can then be easily 
 removed, but even if they should accidentally en- 
 ter the digestive tract, they pass through the 
 same process as other foreign substances intro- 
 duced into the human system with the food, i. e., 
 they become imbedded in the contents of the in- 
 testinal canal which form a thick mass when they 
 reach the vicinity of the vermiform appendix. 
 
 36 
 
and they are thus excreted with the fecal 
 matter." 
 
 This medical opinion clearly demonstrates that 
 the assertions made in regard to the injurious 
 action of enamel chips are untenable, and it is 
 devoutly to be hoped that they may soon pass 
 into oblivion. The report plainly demonstrates, 
 in fact, that the assertion that inflammation of 
 the blind gut is due to the presence of enamel 
 chips in the intestinal tract rightly belongs to the 
 realm of fiction. 
 
 In continuation of my remarks concerning Ox- 
 ide of Tin, I wish to point out that it is advisable 
 to use this product very carefully, especially when 
 it is intended for fine white enamel, inasmuch as 
 some particles of tin are occasionally not com- 
 pletely oxidized and the oxide consequently con- 
 tains a percentage of metallic tin. 
 
 The fired ware, or even utensils which have 
 only received a coating of enamel, very fre- 
 quently show black specks which indicate the 
 presence of metallic tin. 
 
 On observing the presence of these specks, a 
 certain quantity of the Tin Oxide should at once 
 be washed in water. The grayish granular pre- 
 cipitate which is subsequently found on the bot- 
 tom of the vessel consists of metallic tin. 
 
 37 
 
In the up-to-date method of enamel prepara- 
 tion, the Oxide of Tin is added exckisively when 
 the other ingredients are in the grinding mill. 
 
 COBALT. 
 
 In olden times miners were apt to find in their 
 ore workings heavy, glittering pieces of ore from 
 which they hoped to obtain a large output of sil- 
 ver. When treated in the smelting furnace these 
 pieces would, however, soon disintegrate and 
 form gray ashes, while generating a gas having 
 a peculiar odor, similar to that of garlic, and the 
 disgusted miners would consequently throw their 
 disappointing pieces of ore away and called them 
 "Kobolds," the old name of the malicious sprites 
 which were supposed to be constantly fooling the 
 miners. 
 
 In our days, however, these pieces of ore are 
 no longer neglected, but considered exceedingly 
 valuable, because chemistry has discovered that 
 these "Kobolds" contain a metal which enables 
 us to impart an intensely blue color to glass 
 fluxes. The modernized name of this metal is 
 COBALT. 
 
 The reason why this metal had not been found 
 long ago in these deceptive pieces of ore is to be 
 found in the different construction of the old 
 
 38 
 
smelting furnaces which did not by any means 
 generate the heat required for smelting Cobalt 
 ores. 
 
 By constantly keeping Cobalt at the glowing 
 point while freely admitting atmospheric air it 
 may be oxidized without melting the metal, the 
 oxide being of a dark blue color. If Cobalt is 
 kept at glowing heat during a still longer period, 
 and subjected to a roasting process, it will absorb 
 an additional volume of oxygen and is converted 
 into the black oxide of Cobalt (CO.-? O4), which 
 is a highly important factor in the enameling in- 
 dustry. 
 
 CLAY. 
 
 Clay is one of the most important substances 
 used in Enameling Works, and it is unfortunate 
 that it generally fails to receive the careful at- 
 tention it deserves. Many defects for which 
 various alleged explanations are offered must, in 
 fact, be attributed to the quality of the Clay. 
 
 The grade of Clay best adapted for our pur- 
 pose is the so-called "Vallendar"' Clay, found in 
 the vicinity of Coblenz-on-the- Rhine (Ger- 
 many ) . 
 
 No matter what grades of Clay are used, they 
 should always be soaked in pure water for a 
 
 39 
 
period of 24 hours, before being used in the 
 preparation of Enamel, inasmuch as the soaking 
 process will remove from the Clay all the organic 
 substances it contains. The process develops fer- 
 mentation, which can be considerably hastened 
 by the introduction of steam. The Clay is sub- 
 sequently boiled for half an hour, by the end of 
 which time all the gaseous fermentation products 
 will have been carried off. 
 
 After passing through the boiling process, the 
 Clay is run through a fine screen, and the mass 
 is then allowed to stand and the water which col- 
 lects on the surface poured off. The Clay is then 
 ready for being added to the enamel while it is 
 in the grinding mill. 
 
 A certain quantity of Clay, prepared as above 
 described, should always be kept on hand. 
 
 WATER. 
 
 Necessity compels the manufacturer to be 
 thoroughly acquainted with the quality of the 
 water supplied to his works. The success he ob- 
 tains with his products is largely dependent on a 
 supply of water well adapted for the purpose for 
 which it is used. 
 
 In Enameling Works, rain water is unquestion- 
 ably preferable to any other kind. 
 
 40 
 
One or two large cisterns of sufficient capacity 
 to supply the required amount of water are sunk 
 into the ground and all the rain water that can 
 be collected is run from the roofs into these cis- 
 terns. A small pump, installed in the grinding- 
 mill room, lifts the required amount of water 
 from the cisterns and feeds it to the mills. 
 
 If it is absolutely necessary to use water from 
 the city or town water supply, which is generally 
 very soft, it should be run into large vats, where 
 a small amount of lime is added, and the water 
 allowed to stand. As soon as the lime has settled 
 on the bottom of the vats, the water can then be 
 used for mixing with the Enamel in the grinding 
 mill. 
 
 Condensation water should never be used, no 
 matter how pure it may be. 
 
 Some manufacturers have installed water fil- 
 tering plants in their works, animal coal filters 
 being most suitable for our purposes because they 
 w^ll retain all solid substances, but as all filtering 
 processes involve a considerable expense, we 
 would urgently advise manufacturers to collect 
 the rain water, as above described. 
 
 Before entering upon a description of the en- 
 ameling process proper, I shall proceed to insert 
 for the benefit of my readers a number of reliable 
 
 41 
 
formulas for the preparation of Enamel. In se- 
 lecting these formulas, the author's principal con- 
 sideration has been to publish in this volume, as 
 a guide for his readers, only such as he has per- 
 sonally and practically tested. Any manufac- 
 turer may, moreover, use any of the following- 
 formulas, without any further preparation, for 
 making his enamels in accordance with the direc- 
 tions given in this Manual. 
 
 GROUND COAT NO. i. 
 
 IvBS. OZ 
 
 Feldspar 60 
 
 Quartz 52 
 
 Borax 80 
 
 Soda Ash 20 
 
 Fluorspar 8 
 
 Calcspar 8 
 
 Saltpeter 8 
 
 Oxide of Cobalt 
 
 Oxide of Manganese 14 
 
 When charging the ]\Iill add 9% Clay. 
 
 42 
 
 / 
 
GROUND COAT NO. 2. 
 
 LBS. OZ 
 
 Feldspar 56 
 
 Quartz 40 
 
 Borax 60 
 
 Soda ash 20 
 
 Saltpeter 9 
 
 Fluorspar 12 
 
 Oxide of Manganese 2 
 
 Oxide of Cobalt } 
 
 When charging- the JMill, add 10% of Clay. 
 
 GROUND COAT NO. 3. 
 
 LBS. OZ 
 
 Feldspar 51 
 
 Quartz 82 
 
 Borax 86 
 
 Soda Ash 18 
 
 Saltpeter 18 
 
 Calcspar 22i 
 
 Fluorspar 20 
 
 Oxide of Cobalt 4 
 
 Oxide of Manganese 2 
 
 When charging the Mill, add 6% Clay, and 1% 
 Borax, dissolved in W^ater. 
 
 43 
 
GROUND COAT NO. 4. 
 vis: A. 
 
 LBS. oz 
 
 Feldspar 84 
 
 Quartz 58 
 
 Borax 92 
 
 Soda AshK%. P:,} 26 
 
 Saltpeter .'"^(j. 16 
 
 Fluorspar 12 
 
 Oxide of Cobalt. CMi^/^.^ 13 
 
 Oxide of Manganese ... (.< t"j 7 
 
 vis: B. 
 
 LBS. oz. 
 
 Feldspar 128 
 
 Quartz 16 
 
 Borax 108 
 
 Soda Ash 12 
 
 Saltpeter 9 
 
 Fluorspar 26 
 
 Magnesia Carbonate . '| vv^^. 2 
 
 Oxide of Cobalt 13 
 
 Oxide of Manganese 7 
 
 When charging the Mill, take 1/3 of vis: A. 
 and 2/3 vis: B., also 9% Vallendar Clay, 10% 
 ground Glass, and 1% Borax dissolved. 
 
 44 
 
DARK BLUE. 
 
 LBS. OZ. 
 
 Feldspar 120 
 
 Quartz 'J2 
 
 Borax 80 
 
 Cryolite 30 
 
 Saltpeter 7 
 
 Oxide of Cobalt 7 8 
 
 Oxide of Manganese i 
 
 When charging the Mill, add 4% white Clay. 
 BLACK. 
 
 LBS. OZ. 
 
 Feldspar 35 
 
 Quartz 60 
 
 Borax 75 
 
 Soda Ash 27 
 
 Fluorspar 15 
 
 Saltpeter 12 8 
 
 Oxide of Manganese 15 
 
 Oxide of Cobalt 2 8 
 
 Black Oxide of Copper 3 
 
 When charging the Mill, add 9% Clay. 
 
 45 
 
WHITE NO. I. 
 
 LBS. OZ 
 
 Feldspar 55 
 
 Quartz 24 
 
 Borax 24 
 
 Cryolite 18 
 
 Soda Ash 8 
 
 Fluorspar 5 
 
 Clay 6 
 
 Saltpeter 5 8 
 
 When charging the Mill, add 9% Vallendar 
 Clay, and 10% Oxide of Tin. 
 
 WHITE NO. 2. 
 
 LBS. OZ. 
 
 Feldspar 67 
 
 Quartz 90 
 
 Borax 45 
 
 Soda Ash 18 
 
 Boracic Acid 20 8 
 
 Saltpeter 9 
 
 Cryolite 41 
 
 Fluorspar 9 
 
 When charging the ]\Iill, add 12% Vallendar 
 Clay, 12^^ Oxide of Tin, 1% Soda Ash. 
 
 46 
 
WHITE NO. 3. 
 
 LBS. OZ. 
 
 Feldspar 76 
 
 Quartz 48 
 
 Borax 46 
 
 Soda Ash 10 
 
 Cryolite 23 
 
 Saltpeter 7 
 
 When charging the Mill, add 10% of Vallendar 
 Clay and 10% Oxide of Tin. 
 
 WHITE NO. 4. 
 White Powder Enamel for Signs. 
 
 LBS. OZ. 
 
 Boracic Acid 12 
 
 Quartz 40 
 
 Cryolite 18 
 
 Red Lead 14 
 
 Soda Ash 2 8 
 
 Saltpeter i 4 
 
 When charging the JMill, add 10% Oxide of 
 Tin; after milling dry it, and use a 90-Mesh 
 Screen for powdering. 
 
 47 
 
EDGING BLUE. 
 
 LBS. OZ 
 
 Feldspar 64 
 
 Qwartz 54 
 
 Borax 90 
 
 Soda Ash 23 
 
 Fluorspar 16 
 
 Saltpeter ii 
 
 Oxide of Cobalt 5 
 
 Oxide of Manganese 2 
 
 This Enamel must be smelted twice, and when 
 charging the Mill, add 6% white Clay. 
 
 EDGING BLACK. 
 
 I.BS. OZ. 
 
 Feldspar 36 
 
 Quartz 36 
 
 Borax 80 
 
 Soda Ash 18 
 
 Fluorspar 12 
 
 Saltpeter 10 
 
 Oxide of Manganese 8 
 
 Oxide of Cobalt i 12 
 
 Oxide of Copper i 12 
 
 Oxide of Nickel i 8 
 
 When charging the Mill, add 5% brown Clay. 
 48 
 
COPPER BROWN. 
 
 LBS. OZ 
 
 Feldspar 50 
 
 Quartz 15 
 
 Borax 21 
 
 Soda Ash 15 
 
 Fluorspar 6 
 
 Saltpeter 3 
 
 Cryolite 2 
 
 Red Oxide of Iron 12 
 
 When charging the Mill, add 5% Clay, and 4% 
 Red Oxide of Iron. 
 
 GREEN. 
 
 IvBS. OZ 
 
 Feldspar 30 
 
 Quartz 52 
 
 Borax 65 
 
 Soda Ash 20 
 
 Saltpeter 12 
 
 Fluorspar 15 
 
 Black Oxide of Copper 12 
 
 When charging the Mill, add 3% white Clay. 
 
 All of the foresfoino- formulas are exclusively 
 for enameling sheet-steel ware, and I am con- 
 vinced that any one engaged in this line of manu- 
 facture will be able to prepare on the basis of my 
 
 49 
 
said formulas any kind of Enamel required in the 
 production of enameled sheet-steel ware. 
 
 For making other colored Enamels, the only 
 thing- required is a flux, to which the coloring 
 substances, which can be readily purchased in any 
 form desired, are added in the mill, to be ground 
 with the ingredients for the flux. 
 
 During the past ten years the manufacture of 
 enameled signs has grown to enormous propor- 
 tions, chiefly on account of their durability, 
 weatherproof qualities and artistic design. 
 
 In this manufacturing line the ordinary wet 
 enamel is used for large signs, while it is advis- 
 able to use powdered enamel for small-sized signs. 
 The following formulas will be found very useful 
 for preparing various powdered enamels, 
 
 WHITE NO. I. 
 
 LBS. OZ. 
 
 Feldspar 39 
 
 Quartz 64 8 
 
 Boracic Acid 18 
 
 Cryolite 4 
 
 Potash 9 
 
 Soda Ash 6 
 
 Red Lead 36 
 
 Oxide of Antimony, White 16 
 
 50 
 
WHITE NO. 2. 
 
 LBS. OZ. 
 
 Feldspar 37 
 
 Quartz 56 
 
 Boracic Acid 15 8 
 
 Cryolite 6 
 
 Potash 9 
 
 Soda Ash 4 
 
 Red Lead 28 8 
 
 Oxide of Antimony, White 14 
 
 YELLOW. 
 
 LBS. OZ. 
 
 Feldspar 15 
 
 Quartz 23 
 
 Sand 35 
 
 Boracic Acid 48 
 
 Cryolite 23 
 
 Red Lead 160 
 
 Saltpeter i 6 
 
 Magnesia Carbonate 10 
 
 Soda Ash 14 
 
 Oxide of Tin 20 
 
 Oxide of Antimony 21 
 
 51 
 
RED. 
 
 LBS. OZ. 
 
 Feldspar 12 
 
 Quartz 5 6 
 
 Boracic Acid 8 
 
 Red Lead 14 
 
 Cryolite 2 
 
 Soda Ash 4 
 
 Potash 4 
 
 Oxide of Tin 2 
 
 Red Oxide of Iron 3 8 
 
 Magnesia Carbonate 2 
 
 BROWN. 
 
 LBS. OZ. 
 
 Feldspar 22 
 
 Quartz 27 8 
 
 Boracic Acid 55 
 
 Cryolite 12 
 
 Red Lead 100 
 
 Saltpeter 6 
 
 Soda Ash 12 
 
 Red Oxide of Iron 8 8 
 
 52 
 
BLUE. 
 
 LBS. OZ 
 
 Feldspar 23 
 
 Quartz 24 
 
 Boracic Acid 27 
 
 Red Lead 11 
 
 Cryolite 3 
 
 Soda Ash 11 
 
 Bone Ash 4 
 
 Potash II 
 
 Oxide of Cobalt 2 12 
 
 However, as stated before, poorly mixed 
 ingredients cannot produce a homogeneous 
 enamel, and if small amounts of a poorly made 
 mixture are charged into the smelting furnace 
 it becomes impossible for the various ingredients 
 to partly remedy during the smelting process the 
 lack of homogeneity due to inadequate mixing. 
 
 It is consequently absolutely necessary that all 
 the ingredients that have been weighed and mixed 
 be charged in one batch into the smelting furnace. 
 
 If a manufacturer makes, for instance, a mix- 
 ture weighing 1,000 pounds, and smelts the same 
 in two batches of 500 pounds each, then the com- 
 
 53 
 
position of each batch would not be in conformity 
 with the original formula, and the use of the 
 enamel produced with the same would result in 
 the production of defective goods. 
 
 54 
 
The Smelting Process 
 
 From the mixing-room the enamel composition 
 is conveyed to the smelting furnaces, which are 
 generally vat furnaces, burning coal, oil or gas. 
 It is of the utmost importance to have the 
 smelting furnaces, and particularly the furnace 
 bottoms, sufficiently heated before putting in the 
 charge of Enamel, as it is evident that the top of 
 the mass is exposed to the greatest heat, while 
 the only heat it receives from the bottom is that 
 which has been stored up by previously heating 
 the empty vat. It is true that the heat will 
 naturally be conducted from the top to the bottom, 
 but the upper part of the mass, nevertheless, 
 receives more heat than the lower part. 
 
 After a charge has been taken from the fur- 
 nace, the latter should always remain empty for 
 a short time, in order to store up a sufficient 
 amount of heat in the bottom. 
 
 It is exceedingly advisable to have the mass 
 stirred up or raked over at short intervals while 
 in the furnace, in order to equalize the uneven 
 
 55 
 
heating. In this connection it is well to bear in 
 mind that the Enamel will be all the more homo- 
 geneous if each layer of the mass receives an 
 ec|ual amomit of heat. 
 
 This stirring or raking over is, in fact, one of 
 the factors which determine the result. During 
 the smelting process the ingredients of the mass 
 will at first separate to a certain extent. The 
 substances which have a low fusing point will 
 fuse first, while those which have a high fusing 
 point have a tendency to settle down to the 
 bottom of the furnace. 
 
 In case of failure to frequently and thoroughly 
 rake over the mass while it is in the furnace, the 
 silicates will not, therefore, be rendered evenly 
 soluble, and the enamel will consequently be of 
 inferior quality. 
 
 The man whose duty it is to charge and dis- 
 charge the furnaces knows exactly when the time 
 for running off has arrived. He can observe the 
 interior of the muffle through the peep holes, and 
 as soon as all ebullition ceases and the mass 
 remains as smooth as a mirror after having been 
 stirred up for the last time, the charge is ready 
 for tapping. 
 
 After the furnace tender has opened the door 
 the Enamel is run off into a large tank filled with 
 
 56 
 
cold water, and breaks up into small particles, in 
 consequence of the sudden chill. 
 
 Only a reliable workman can, of course, be 
 employed for conducting the smelting operation, 
 as every man conversant with the trade knows 
 the annoyances and disappointments resulting 
 from the use of Enamel that has either not been 
 smelted to a finish or been burnt in the smeltins:. 
 
 5: 
 
The Grinding Process 
 
 From the smelting furnace the Enamel is con- 
 veyed to the grinding room, which must be the 
 cleanest room in the works, and is to be kept free 
 from every particle of dust. 
 
 At the present time Enamel is exclusively 
 ground in pebble mills, lined on the inside with 
 hard porcelain bricks. When once these mills are 
 charged and in operation they require compar- 
 atively little power. 
 
 For grinding very fine enamels it is advisable 
 to use the French pebble mills or else mills with 
 drum and balls of hard porcelain, because the 
 use of these mills makes it absolutely impossible 
 for any particles of cement or iron to become 
 mixed with the Enamel during the grinding. 
 
 The pebble mills must be carefully inspected 
 at intervals to ascertain whether the porcelain 
 bricks have worn out. If so, the mill must be 
 provided with a new lining. 
 
 In the grinding room the Enamel is weighed 
 out in batches corresponding to the capacity of 
 
 58 
 
the mill and charged into the mill with a propor- 
 tional amount of pure, clear water. 
 
 Inasmuch as water alone will not thoroughly 
 combine with Enamel, a certain percentage of 
 clay, figured on the basis of the weight of the 
 Enamel, must be added to each batch of the 
 latter. 
 
 This admixture of clay serves the purpose of 
 keeping the ground Enamel suspended in the 
 liquid and prevents it from settling on the bottom. 
 
 The preparation of the clay has been described 
 in a previous chapter (see chapter "Clay"). 
 
 In order to make white Enamel absolutely 
 white and thoroughly opaque, a percentage of 
 oxide of tin, figured according to the quality of 
 the Enamel, must be added when the latter is in 
 the mill. 
 
 Some works are following the reprehensible 
 practice of running ofif the Enamel from the mill 
 into high, narrow barrels as soon as it has been 
 sufficiently ground. This method should never 
 be used under any circumstances, because heat is 
 frequently generated in the mill by friction 
 between the small round pebbles and the Enamel, 
 which makes it necessary to run ofif the finished 
 Enamel into large, flat tanks, lined with zinc, 
 where it can cool at once. 
 
 59 
 
When the Enamel is run off into barrels, as 
 aforesaid, it will retain its heat for a considerable 
 time, and when such Enamel is used for the sheet- 
 iron ware it will become dull during the firing 
 process, inasmuch as the Enamel has become 
 devitrified by being allowed to retain its heat 
 too long. 
 
 Before using the ground Enamels for coating 
 the utensils they must be tested for their density. 
 Should they prove to be too thin they must be 
 slightly thickened or given the right body. This 
 is accomplished by adding a solution of sal 
 ammoniac, common salt, magnesia, Epsom salts 
 or borax, drop by drop, to the Enamel. In this 
 connection it appears advisable to state that the 
 thickening should never be entrusted to the men 
 who are employed in coating the ware, because 
 they will always give the Enamel the body wdiich 
 makes their work, i. e., the coating, easiest. 
 
 When Enamels are ground very fine they will 
 have a more brilliant gloss than coarsely ground 
 Enamels, but they should, nevertheless, not be 
 ground too fine, as they are liable to become 
 viscid and produce a streaky coating, from which 
 even the most skilful coater cannot remove the 
 streaks. 
 
 About 1% red oxide of iron should be added 
 
 60 
 
to dark blue Enamel, as it gives it a richer 
 coloring. 
 
 For making all other kinds of colored Enamel 
 it is generally sufficient to use a glazing, to which 
 the various coloring materials are added while in 
 the mill. The amount of oxide of tin or cryolite 
 to be added to the mass depends on whether the 
 Enamels are to be light or dark colored. If very 
 dark shades are to be produced the oxide of tin 
 and cryolite are entirely omitted, while at the 
 same time adding a correspondingly larger 
 amount of coloring matter. 
 
 61 
 
The Coating and Firing 
 Processes 
 
 After the crude ware has been pickled and the 
 dents, if any, have been beaten out, it is conveyed 
 to the enameHng or coating room proper. In 
 this room pans of adequate size for holding the 
 utensils are imbedded in the tables, the rims of 
 the pans being level with the table top. Behind 
 each pan is placed a large screen, the lower part 
 of which points in the direction of the pan. 
 These screens serve the purpose of catching up 
 at once the Enamel which is squirted in a forward 
 direction and of conveying it back into the coating- 
 pan. 
 
 The pans and screens must have a ground coat 
 of Enamel, so as to prevent rust or iron from 
 becoming mixed with the coating Enamel. 
 
 A further requirement is a number of shelves, 
 adjusted to the height of the utensils which are 
 left to dry on these shelves. The furnace flues 
 are generally made to pass under the shelves, so 
 
 62 
 
as to utilize the heat of the flames while they are 
 carried off. 
 
 The first coating which the crude ware receives 
 is a coat of ground coat enamel. 
 
 The essential quality of ground coat enamel is 
 that it has a comparatively low fusing point. It 
 contains either an admixture of oxide of cobalt 
 or of oxide of nickel and manganese. 
 
 These metallic oxides, in conjunction with 
 borax, impart to the Enamel a coefficient of 
 expansion which is approximately the same as 
 that of sheet steel. 
 
 Ground coat enamels to which only oxide of 
 nickel has been added (known as nickel ground 
 coat enamels) require a great deal of care and 
 attention during the coating and firing processes, 
 and they are not as durable and elastic as cobalt 
 ground coat enamel. 
 
 Ground coat enamel must not be ground too 
 fine, and the coating must be rather thin. When 
 a ground coat is put on too thick it is liable to 
 scale off and to produce the exceedingly annoying 
 minute cracks or chinks. Care should also be 
 taken to put on a thin coat under the rims and 
 over the seams, as blisters are otherwise liable to 
 appear in these places. 
 
 It is essential to dry the ware quickly after 
 
 63 
 
the ground coat has been put on, in order to 
 prevent rusting under the enamel. Recourse is 
 also frequently had to a slight addition of borax 
 solution for the purpose of preventing rust stains. 
 After the ground coat has been put on and 
 dried, the ware should not be passed on to the 
 kiln before it has been inspected for the purpose 
 of ascertaining whether there are any spots in 
 which the metallic surface can be seen through 
 the enamel. If so, these spots must be coated 
 over, inasmuch as the metal in these places would 
 otherwise be converted during the firing process 
 into black oxide of iron, to which the subsequent 
 coating of white enamel will not adhere. All the 
 ware fired without recoating these spots would 
 consequently be either seconds or refuse. 
 
 We have for a long time past been trying to 
 make a white ground coat enamel without an 
 addition of the oxides of cobalt or nickel, and 
 numerous experiments have been made, regard- 
 less of expense. All efforts, however, proved to 
 be in vain, and all technical men in the enameling 
 trade now concur in the opinion that any further 
 attempts to produce such an enamel would merely 
 be a waste of time. 
 
 After the ground coat has been fired on the 
 ware, a process which requires a very high 
 
 64 
 
temperature, in order to convert the large per- 
 centage of borax contained in the enamel into 
 a thin liquid which will enter into a close combi- 
 nation with the sheet steel, the ware is subjected 
 to the second operation, viz., that of receiving its 
 first coat of white enamel, which should be com- 
 paratively thin. 
 
 In order to produce very handsome ware it is 
 advisable to put on the blue or black rim when 
 the ware has received its first white enamel coat. 
 This putting on of the rims should be done very 
 carefully, as a fine, clean rim will give the ware 
 an attractive appearance. 
 
 There are different methods of putting the rim 
 on the ware, and their selection will largely 
 depend on the question whether the enameling 
 foreman has been accustomed to one or the other 
 of these methods, i. e., whether he has put them 
 on by hand or on a glass or steel plate. The 
 latter method is preferable, because it produces 
 a cleaner and more even rim. 
 
 After drying the first coating of white enamel, 
 which should, if possible, be done without using 
 the heat from the furnace flues, and merely by 
 the atmospheric air, the ware is again passed on 
 to the kiln and fired at low heat. 
 
 After this operation the ware is given its 
 
 65 
 
second and last coating of white enamel, which 
 is intended to give the goods an attractive appear- 
 ance, and should consequently be carefully put 
 on, without streaks. 
 
 It is one of the duties of the foreman of the 
 enameling shop to construct such tools for coating 
 and firing as will protect the ware from being- 
 bent out of shape, so as to avoid, as far as 
 possible, the necessity of straightening out the 
 utensils after the firing operation. Straightening 
 out is, in fact, liable to injure the rims, as they 
 will in certain places scale off and leave the iron 
 surface exposed, a defect which means more 
 seconds and refuse. 
 
 It is, moreover, exceedingly important to have 
 the unfinished ware which is to be enameled most 
 carefully made in every respect. The folded 
 seams and the riveting should be solid, the rims 
 either tightly closed or entirely open, and in 
 making stamped ware special care should be 
 taken to give the bottom the proper tension, as 
 the enamel will frequently scale off, during the 
 heating, in the middle of the bottom, owing to 
 the uneven tension, a defect which means no end 
 of annoyances for the manufacturer. 
 
 This defect, however, can be easily remedied 
 by stamping an embossed ornament, or better still, 
 
 66 
 
the trademark, in the middle of the bottom, 
 where it will take up all the surplus material, 
 thereby leaving the bottom free to warp in both 
 directions. 
 
 There are too many possible manufacturing 
 defects, and too many possible causes for the 
 same, to discuss them all in this volume. I shall, 
 however, enumerate a few of the defects which 
 are of most frequent occurrence, stating at the 
 same time their possible causes, hoping to thus 
 assist many manufacturers in discovering the 
 mistakes to which such manufacturing defects as 
 they may have observed in their product are to 
 be attributed. 
 
 1. Scaling off of the enamel on the bottom and 
 at the rims. 
 
 Possible Causes: Uneven tension in the bot- 
 tom. The use of too hard enamel on the rims. 
 Too much annealing. Ground coat enamel fired 
 at too low a heat. Moisture in the rolled rims. 
 
 2. Blisters forming streaks on certain parts of 
 the utensils. 
 
 Possible Causes: Too thick a coating of ground 
 coat enamel. The ground coat enamel does not 
 properly correspond with the covering enamel. 
 The presence of too large a percentage of 
 fluorspar in the enamel. Firing at too low a heat. 
 
 67 
 
3- Blisters irregularly distributed and of 
 irregular size. 
 
 Possible Causes: Insufficiently smelted enamel. 
 The use of clay containing organic matter. Ware 
 insufficiently annealed and pickled. 
 
 4. White specks in colored enamel. 
 
 Cause: The ware was placed with moist hands 
 on the firing bars. 
 
 5. Disappearance of the gloss. 
 
 Possible Causes: An inflow of gases through 
 the leaky walls of the muffle while the furnace 
 was charged. Devitrification due to repeated 
 firing. 
 
 All of the aforesaid defects demonstrate that 
 absolute cleanliness is a necessary requirement 
 in all stages of the enameling process. 
 
 The well-known muffle furnaces of various 
 types of construction, burning coal, oil or gas, are 
 used as kilns for firing the enamel. 
 
 Furnaces without muffles are in operation in a 
 few works, but their use cannot be recommended, 
 because the fire must be turned ofif each time 
 they are charged, such furnaces being conse- 
 quently never evenly heated while the charge is 
 put in. Moreover, there is frequently an accumu- 
 lation of gases which have a most injurious effect 
 on the articles to be fired. 
 
 68 
 
In this connection we would add that it is 
 advisable to provide reliable pyrometers for veri- 
 fying the proper temperature both in muffle and 
 smelting furnaces, inasmuch as the use of Seger 
 cones does not only take a good deal of time, but 
 is also very expensive. 
 
 69 
 
The Coefficients of Expan- 
 sion of Sheet-Steel 
 Enamels 
 
 Some exceedingly valuable and interesting tests 
 have been made at the Polytechnic of Karlsruhe 
 (Germany) in regard to the coefficients of expan- 
 sion of sheet-steel enamel and of various grades 
 of sheet steel. The report concerning these tests 
 reads as follows: 
 
 "By direct determination of the coefficients of 
 expansion according to the Fuers method, we 
 were able to prove that the assumption that 
 ground coat enamels served the purpose of equal- 
 izing the difference in expansion between the 
 covering enamel and the steel is not based on fact, 
 inasmuch as the coefficient of expansion of 
 ground coat enamels is even slightly lower than 
 that of coating enamels. Changes in the amount 
 of borax added to the enamel do not materially 
 alter its expansion capacity. The coefficient of 
 expansion of the various grades of sheet steel 
 
 70 
 
were found to be from 20% to 30% higher than 
 those of any of the enamels tested. The coefficient 
 of expansion of steel decreases by ^7^ by coating 
 with ground coat enamel, and by 10% by coating 
 with both ground coat and covering enamel. 
 There are consequentl}^ very high tensions in 
 enameled utensils, and this furnishes an explana- 
 tion of the fact that enameled ware will very 
 frequently crack and split without any external 
 cause." 
 
 71 
 
Cast-iron Enameling 
 
 Enamels for cast-iron ware require entirely 
 different treatment and are of different composi- 
 tion than sheet-steel enamels. 
 
 Utensils for cooking and chemical purposes 
 are known in the trade as "cast pottery." 
 
 Only fritted ground coat compositions are 
 used for ware of this kind. The trade term 
 "fritted" applies to such mixtures as have only 
 been brought to the slagging point. 
 
 These frit mixtures are charged into the muffle 
 furnace in a flat pan, lined with clay, and left in 
 the furnace until they are converted into a 
 porous, spongy mass. 
 
 After passing through this slagging process 
 the mass is ground in a wet mill w4th admixtures 
 of clay, feldspar, quartz, etc. 
 
 I give below a few formulas for ground coat 
 
 frit: 
 
 FRIT NO. I. 
 
 LBS. OZ. 
 
 Sand 36 
 
 Borax 9 
 
 72 
 
When charging the mill, add 30% quartz and 
 10% clay. 
 
 FRIT NO. 2. 
 
 LBS. OZ. 
 
 Sand 44 
 
 Borax 19 
 
 Saltpeter 14 
 
 When charging the mill, add 9% quartz and 
 12% clay. 
 
 FRIT NO. 3. 
 
 LBS. OZ. 
 
 Sand 36 
 
 Borax 15 
 
 Carbonate of Magnesia i 2 
 
 When charging the mill, add 25% clay. To 
 hold up, use soda phosphate. 
 
 WHITE FOR POTTERY. 
 
 LBS. OZ 
 
 Feldspar 39 
 
 Sand 30 
 
 Borax 30 
 
 Soda Ash 24 
 
 Fluorspar 9 
 
 Whitening 4 8 
 
 Oxide of Zinc 6 
 
 When charging the mill, add 14/^ oxide of tin, 
 7% oxide of zinc, 7% clay. 
 
 71 
 
The sand blast provides a very efficient means 
 for cleaning cast-iron ware. Acids of any kind 
 should never be used for this purpose. 
 
 After the cast ware has been cleaned a thin 
 ground coat is put on, dried and fired at red heat. 
 After firing, the ground coat must have a rough 
 surface and no gloss. 
 
 After cooling the ware thoroughly the ground 
 coat is moistened with a sponge and the white 
 enamel first thoroughly rubbed in with a brush, 
 so as to fill all the pores of the ground coat. The 
 white enamel is thereupon poured over every 
 part of the utensils, which are subsequently 
 struck lightly with a wooden hammer in order 
 to make the enamel run off evenly. 
 
 It is absolutely necessary to cool the fired cast- 
 iron ware slowly. 
 
 Large-sized articles are enameled by the dry 
 method, for which powdered enamel is used. 
 This is spread through a sieve over the metal 
 surface of the utensils, while they are at red heat, 
 and without any ground coat. 
 
 74 
 
Majolica Ware Enamels 
 
 The production of enameled ware in imitation 
 of Majolica ware is no longer a difficult matter. 
 Art castings, such as high-grade gas stoves, gas 
 ranges, etc., made in ornamental style, are 
 exceedingly well adapted for this kind of 
 enameling. 
 
 When fired at a high temperature Majolica 
 ware enamel will flow into the recesses of the 
 casting and leaves only a slight gloss on the 
 protruding parts. The recesses will consequently 
 be of a darker shade than the protruding parts, 
 and the casting will thus have the appearance of 
 Majolica ware. 
 
 Articles to be enameled in imitation of Majol- 
 ica must first receive a ground coat, and subse- 
 quently, after firing, a coat of white enamel, 
 whereupon they are subjected to a second firing- 
 process. When thus prepared the colored enamel 
 wall stand out splendidly on the white ground. 
 
 It is not absolutely necessary to use a special 
 kind of ground coat enamel, as the ordinary 
 ground coat enamel for cast pottery will answer 
 the purpose. 
 
 75 
 
WHITE GROUND COAT FOR MAJOLICA 
 WARE IMITATION. 
 
 LBS. OZ. 
 
 Feldspar 15 
 
 Quartz 12 
 
 Boracic Acid 7 8 
 
 Soda Ash 4 8 
 
 Red Lead 3 8 
 
 Whitening 3 8 
 
 Oxide of Zinc I 8 
 
 Oxide of Antimony I 4 
 
 Saltpeter i 6 
 
 FLUX FOR MAJOLICA COLORS. 
 
 LBS. OZ. 
 
 Feldspar 10 
 
 Quartz 22 
 
 Borax 12 
 
 Red Lead 62 
 
 Soda Ash 6 
 
 Saltpeter 2 8 
 
 Oxide of Tin 3 8 
 
 The various coloring matters are added in the 
 mill, according to the shade desired. 
 
 It is advisable to smelt all enamels intended 
 for Majolica imitation in the crucible, and to 
 
 76 
 
smelt them twice. After the first smelting the 
 contents of the crucible should be allowed to drip 
 out into a dry receptacle, and after the second 
 smelting into a pan filled with pure water. 
 
 The grinding process is conducted in the same 
 manner as for any other enamels, in a pebble mill 
 with porcelain balls, but care should be taken to 
 grind all enamels intended for this purpose 
 exceptionally fine. It is absolutely necessary to 
 keep Majolica glazings made by this method in 
 tightly closed containers until they are used. 
 
 in 
 
Enamel Painting 
 
 After placing their white utensils, resembling 
 chinaware, upon the market, the Enameling 
 Works were soon compelled to avail themselves, 
 as far as possible, of the art of enamel painting 
 and to delve into its secrets, so as to impart to 
 their enameled utensils the closest possible 
 resemblance to the products of the chinaware 
 industry. 
 
 Those who have an opportunity to inspect the 
 finely decorated enameled ware exhibited at the 
 present time by importing firms in New York 
 and other cities cannot fail to marvel at the 
 diversity of designs and at the splendid efifect of 
 the artistic decorations which embellish these 
 articles. 
 
 Enamel painting and china painting are two 
 closely related professions, although not wholly 
 similar. The principal difference consists in the 
 composition of the smelting fluxes. 
 
 These fluxes, mostly lead fluxes, are added in 
 varying proportions to the colors which are com- 
 
 78 
 
posed of a series of metallic oxides, for the pur- 
 pose of obtaining the desired firing point. The 
 painter must be thoroughly conversant with the 
 fusing point of his colors and he must always 
 select the proper flux for each color, because 
 some colors will stand more heat than others. 
 
 Hand painting is principally used for special 
 utensils or ware, such as trays, tea and coffee 
 urns and fine wash-bowls and pitchers. 
 
 As hand painting, however, is very expensive, 
 manufacturers are at the present time using 
 various substitutes which reduce considerably the 
 cost price of decorated ware. 
 
 One of these substitutes is, for instance, steel 
 plate printing, a method by which the finest 
 shading can be obtained, leaving nothing to do for 
 the painter except to glaze them over with the 
 proper colors. 
 
 The sketching of the decorative designs on the 
 steel plates requires, of course, great artistic 
 ability and intelligence. 
 
 The engraved plates are placed upon a heating 
 plate, heated either by gas or electricity, and kept 
 at moderate heat. The painter then covers the 
 steel plate with his thickly mixed color, which 
 must be of a rather tough consistency, and 
 removes the color from all the parts of the steel 
 
 79 
 
plate which are not engraved by firmly rubbing 
 a piece of stiff paper over the entire surface of 
 the plate. The thin printing paper especially 
 prepared for this purpose is moistened, spread 
 upon the steel plate, both being thereupon passed 
 through a printing press which imprints the sharp 
 outlines on the thin printing paper. 
 
 When the paper has thus been printed it is 
 laid with the printed side on the ware which is 
 to be decorated, pressed down with a moist 
 sponge and all the folds are smoothed down with 
 a hard rubber roller. The paper is thereupon 
 carefully lifted off, when the outlines of the 
 design will appear transferred on the article or 
 utensil. 
 
 The painter now fills in the design with the 
 proper colors and the piece thus decorated is 
 ready for firing. 
 
 Enamel colors are generally so prepared that 
 they will flow very readily, and firing requires the 
 closest attention and the greatest care. 
 
 The so-called ''air-brush work" is another 
 method, and fairly attractive decorations can be 
 obtained with the same with the aid of stencil 
 patterns. 
 
 The cheapest method of decorating enameled 
 
 80 
 
ware, however, is unquestionably the use of 
 ceramic transfer or decalcomania pictures. 
 
 These transfer pictures are made by manufac- 
 turers who make a specialty of this line. They 
 are manufactured by chromo-lithography, with 
 the use of enamel colors and a collodion coating. 
 
 For transferring these ceramic decalcomania 
 pictures properly they are placed for a few 
 minutes in lukewarm water. After making sure 
 that the collodion film has been dissolved, the 
 pictures are spread on the articles which are to 
 be decorated and the backing carefully drawn off. 
 The pictures are then pressed closely against the 
 outside of the article, conforming to its shape, 
 and smoothed down as perfectly as possible by 
 slight pressure with a sponge. 
 
 When this has been done there will still remain 
 a few small blisters formed by water or air, and 
 these are carefully rolled down and smoothed out 
 with a rubber roller. 
 
 The latter work must be very carefully done, 
 as the small blisters would otherwise burst in the 
 furnace, thereby spoiling the entire picture. 
 
 After this operation the articles to which the 
 pictures have been transferred are charged into 
 a dryer, where they must be dried hard before 
 they are conveyed to the kiln or furnace. 
 
 81 
 
Moist pictures would either become entirely 
 detached from the ware while in the kiln, or else 
 they would be torn to pieces. 
 
 Decorated with the picture alone, the ware 
 would have an imperfect appearance. In order 
 to improve it the rims, handles, etc., are striped 
 by the painter either in gold or some other color, 
 the ware being thereupon charged into the firing 
 furnace, in which it must be fired only once. 
 
 The manufacturers of transfer pictures are 
 now making splendid goods which enable the 
 mantifacturer to decorate his product at a very 
 small cost. 
 
 82 
 
Pastel Painting on Enam- 
 eled Paints 
 
 Pastel painting on enamel is an entirely new 
 invention, principally used in art painting for 
 producing portraits on enameled plaques, because 
 such portraits will remain unchanged during 
 many generations. Any fading of the colors on 
 an enameled plaque would be absolutely impos- 
 sible, as the colors are baked at a high temper- 
 ature, and such pictures need not, therefore, be 
 framed under glass. Dust and other impurities 
 can readily be removed by rubbing with a cloth 
 moistened with alcohol. 
 
 The technique of enamel painting is exceed- 
 ingly complicated, and the application of the 
 colors on the smooth surface of the enameled 
 plaque by means of colored crayons requires both 
 a peculiar faculty and artistic talent on the part 
 of the painter. 
 
 Enamel plaques intended for portrait painting 
 must be prepared as follows : 
 
 First of all, the white enamel used for this pur- 
 
 83 
 
pose must be made of the very best materials and 
 ground very fine, so as to obtain a fine grain. It 
 must, moreover, be applied with the utmost care, 
 to avoid all streaks and lumps. 
 
 After the enamel has dried on the plaque it is 
 fired lightly in the muffle furnace. When taken 
 out the surface must be rough, without gloss, 
 because the color from the crayons would not 
 otherwise adhere to it. 
 
 The colored crayons must be made of a certain 
 degree of hardness so they will yield enough color 
 for providing very dark shades whenever 
 required. 
 
 After the drawing of the picture has been 
 completed the plaque goes to the furnace, where 
 it is fired to a finish, and thereby acquires the 
 necessary gloss. 
 
 84 
 
Pastel Crayons 
 
 The painter entrusted with making the crayons 
 must have a thorough knowledge of the colors he 
 intends to use, and be perfectly familiar with 
 their action when baked at a high temperature, 
 if he is to produce a perfect picture. 
 
 The mass used for making pastel crayons is 
 prepared and treated as follows: The color is 
 mixed with a watery solution of gum arable and 
 thoroughly kneaded until a solid mass is obtained 
 which will not change its form after having been 
 allowed to stand for some considerable time. 
 
 After making sure that the mass is of solid 
 consistency, it is divided up into small equal parts, 
 each of which must be sufficient for making one 
 crayon. The parts are then rolled into a cylin- 
 drical shape of the desired thickness and cut 
 down to a convenient length, usually ranging 
 between 5 and 6 inches. 
 
 The crayons must be thoroughly air dried and 
 pointed with a sharp file. They are then ready 
 for the painter. 
 
 85 
 
Only an experienced and intelligent porcelain 
 and enamel painter should, of course, be entrusted 
 with the preparation of the pastel crayons, as the 
 composition of the colors is wholly different from 
 that of ordinary water colors. 
 
 A common paper stump is used for rubbing 
 down the colors. 
 
 This pastel painting method is undoubtedly 
 destined to have a great future and will appeal 
 most favorably to lovers of art. 
 
 86 
 
The Application of Photo- 
 Ceramics to Enamel 
 
 The production of photographs on enamel 
 plaques has during the past few years developed 
 into an independent branch of industry. 
 
 Photographs on enamel plaques can be made 
 without any serious difficulty, the method most 
 generally used being the dusting process. This 
 method is based on the known phenomenon that 
 a mixture of acid potassium chromate, gum, 
 albumen and gelatine will become insoluble under 
 the influence of sun rays. 
 
 The process is as follows : 
 
 A mirror plate is coated with the above 
 described mixture and dried. When dry the plate 
 is exposed to the light under a positive, which can 
 be obtained from the photographer after he has 
 taken a picture. After the plate has been suf- 
 ficiently exposed to the light, the Enamel color is 
 carefully dusted on. As the color will not adhere 
 to the parts of the plate which were exposed to 
 
 87 
 
the light, the dusting has made the picture visible. 
 It is thereupon coated with collodion and treated 
 with alkaline water, in order to dissolve the chro- 
 mium compounds and transfer them with the col- 
 lodion film to the enamel plaque. The collodion 
 is finally removed by dissolving it and the picture 
 is then ready prepared for firing. 
 
 The above described process was invented by 
 two Frenchmen, Messrs. Salmon and Garnier. 
 
BLISS 
 
 ?^=n 
 
 Complete Modern 
 Equipments of 
 
 PRESSES. LATHES 
 DOUBLE SEAMERS 
 SHEARS. DIES AND 
 SPECIAL MACHINERY 
 
 For the Economical 
 Manufacture of 
 
 ENAMELWARE 
 
 TINWARE AND 
 
 METAL PACKAGES 
 
 of every description 
 
 Our machines are fast producers of 
 filgfi -class work. Write stating your 
 requirements. We will be pleased to 
 send estimates on machmes best 
 adapted for economical production. 
 
 Pamphlets of different lines on 
 request. 
 
 E. W. BLISS CO. 
 
 ADAMS ST., BROOKLYN, N. Y. 
 U S. A. 
 
 Representatives for Chicago 
 
 and Vicinity : Stiles-Morse 
 
 Co., 67 West Washington 
 
 St., Chicago. 111. 
 
 European Office : 
 1 00 Boulevard Victor- 
 Hugo, St. Ouen (Paris), 
 France 
 
 London Office : 
 I 14 Queen Victoria St. 
 London, E. C England 
 
THE 
 
 Roessler & Hasslacher 
 
 Chemical Company 
 
 MAIN OFFICE : 
 
 100 William Street 
 
 New York 
 
 FACTORY : 
 
 PERTH AMBOY. N. J. 
 
 BRANCHES : 
 Chicago, III. 
 East Liverpool, Ohio 
 Boston, Mass. 
 Philadelphia, Pa. 
 Kansas City, Mo. 
 
 HIGHEST 
 
 GRADE 
 
 ENAMELING CHEMICALS 
 
 ALSO 
 
 COLORS AND OXIDES 
 
 STAR BRAND 
 
 A 
 / \ 
 
 OXIDE 'SaI. 
 
 T I N 
 
 
■HIGH GRADE— 
 
 MUFFLES 
 
 FOR ENAMELING 
 ANNEALING AND 
 REHEATING 
 
 A Large Variety of Sizes 
 and Styles 
 
 Style K 
 
 Manufactured by 
 
 Brooklyn Fire Brick Works 
 
 88 Van Dyke Street 
 Brooklyn New York City 
 
 Plans and Estimates on Application 
 
 
m 11 ^9^0 
 
 FOUNDED 1869 
 
 J. R. Alsing Engineering Co. 
 
 136 LIBERTY STREET, NEW YORK CITY 
 The Parent Co. of the Pebble Mill Business in America 
 
 are using 
 
 THE ALSING MILLS 
 and a large number of them use our 
 
 CORRUGATED CRUSHING ROLLS 
 
One copy del. to Cat. Div. 
 
 )^