,,how ,,to ,,enamel ,,being ,a ,,treatise ,,on ,,the ,,practical ,,enameling ,,of ,,jewelry ,,with ,,hard ,,enamels ,,by ,,howard ,m4 ,,chapin ,,author ,,of 8,,life ,,of ,,dea4 ,,samuel ,,chapin10 ,,etc4 ,,first ,,edition ,,first ,,thousand ,,new ,,york ,,john ,,wiley ,,sons ,,london3 ,,chapman ,,hall1 ,,limited #aiaa ---------------------------------------- -------------------------------- ,,copyright1 #aiaa ,,by ,,howard ,m4 ,,chapin ,stanhope ,press ,f4 ,h4 ,,gilson ,,company ,,boston1 ,u4,s4,a4 ---------------------------------------- -------------------------------- ,,contents ,,page ,,list ,,of ,,illustrations v ,,preface vii ,,introduction ix ,,chapter ,i ,,preparation ,,of ,,the ,,enamel #a ,,chapter ,,ii ,,preparation ,,of ,,the ,,metals #h ,,chapter ,,iii ,,charging #ad ,,chapter ,,iv ,,firing #bc ,,chapter ,v ,,stoning #bi ,,chapter ,,vi ,,polishing #cg ,,chapter ,,vii ,,foils--,,paillons--,,glitter ,,enamel--,,dull #db ,,finish--,,plique--,,jour ,,chapter ,,viii ,,enamel ,,painting #ej ,,chapter ,,ix ,,photographs ,,on ,,enamel #eg ---------------------------------------- -------------------------------- ,,list ,,of ,,illustrations ,,fig4 ,,page #a ,,agate ,,mortar ,,and ,,pestle x #b ,,grinding ,,with ,,weighted ,,pestle #b #c ,,enameler',s ,,spatula ,,with ,,wooden #aj ,,handle #d ,,charging #ad #e ,,metal ,,tray ,,and ,,tile #bd #f ,,firing #cj #g ,,carborundum ,,or ,,emery ,,stone #cg #h ,,stoning #dd #i ,,pickle ,,pan #ea #aj ,,polishing #eh #aa ,,pickle ,,pot #fe ---------------------------------------- -------------------------------- ,,preface ,the aim of this book is to explain practical enameling in such a way that one entirely unacquainted with the subject will1 after a little study1 not only understand the fundamental principles of the art1 but with a little practice be able actually to achieve creditable results in this most fascinating branch of the jeweler's craft4 ---------------------------------------- -------------------------------- ,,introduction ,enamel is really a glaze applied to metals just as other glazes are applied to porcelain1 glass1 and earthenware4 ,we will confine our attention to what is known as hard enamel in contradistinction to japans1 lacquers1 and enamel paints1 which are often called soft enamels4 ,hard enamels are compounds of glass with different metallic oxides which produce the different colors4 ,these compounds are fused together at a very high temperature and on cooling become extremely hard4 ,they fill the gap between glass and china1 the transparent fondants being to the layman indistinguishable from glass1 while the opaque whites may be easily mistaken for china1 and the countless other varieties form a chain of scarcely perceptible gradations from one extreme to the other4 ,illustration3 ,,fig4 #a4 ,,agate ,,mortar ,,and ,,pestle4 ,the use of enamels is both very ancient and very widespread1 for we find the process known to the ancient ,egyptians and to the ,chinese1 although the highest development in the art was reached in ,france in the sixteenth century4 ,we would refer the historical student to ,cunynghame's 8,european ,enamels0 in ,english and ,luthmer's 8,enamel0 in ,german4 ,jewelry enameling is usually divided into five different classes1 viz3 champlev1 cloisonn1 incrusted1 plique--jour1 and enamel painting4 ,champlev enamel is that in which a part of the metal is cut away1 leaving a depression which is filled with enamel to the level of the surface of the metal1 thus giving a sort of inlaid effect4 ,if the enamel surface is not filed off flat but allowed to have a concave or convex surface the piece is said to be 8flushed40 ,technically enamel is 8flushed0 if it is not 8stoned40 ,when transparent enamels are used and the background under the enamel is cut in relief1 it is called 8,baisse-taille enamel40 ,cloisonn enamel is hardly distinguishable from champlev when finished1 but is made differently4 ,instead of cutting depressions in the metal to hold the enamel1 metal wires are soldered on the smooth surface of the metal1 thus forming partitions or fences between which the enamel is placed4 ,incrusted enamel is that in which the enamel is charged directly on the metal surface without any raised metal edges to hold it4 ,it is generally used in small daubs or beads to reproduce the effect of precious stones4 ,plique--jour enamel is similar to cloisonn except that the wires are soldered to each other without any background1 thus forming a sort of filigree1 the spaces within which1 when filled with enamel1 somewhat resemble a stained-glass window4 ,in enamel painting a picture is painted on the enamel4 ,usually white opaque enamel is used for the background1 and the painting is executed with finely ground enamel or china paints1 after which it is covered with a layer of transparent enamel which serves as a protection for the painting4 ---------------------------------------- -------------------------------- ,,chapter ,i ,,preparation ,,of ,,the ,,enamels ,,enamel is generally bought in the form of hard chunks more or less flat and varying from the size of an acorn to that of a large dinner plate4 ,when it is made it is poured into a mold where it hardens in the form of a disk or slab generally a foot or more in diameter1 and later gets broken into smaller pieces during transportation4 ,these chunks of enamel may be readily broken up by a hammer1 and if they are first wrapped in a piece of cloth the small particles will not fly about and get into one's eye1 and no enamel will be lost4 ,when the enamel has been broken up so that none of the pieces are larger than a pea1 it should be washed in clean water to free it from any dirt that it naturally contained or that it received from the cloth in which it was wrapped during the hammering process4 ,cleanliness cannot be too much emphasized1 for the slightest particle of dirt mixed in with the enamel may often completely spoil a piece of work4 ,enamel if heated quite hot and then plunged into cold water will become so brittle that it can be broken up by the hands1 but when treated in this manner is said to be harder to grind4 ,illustration3 ,,fig4 #b4 ,,grinding ,,with ,,weighted ,,pestle4 ,after the enamel has been broken up into small pieces it should be put in an agate or porcelain mortar and ground to a fine powder4 ,this will take from twenty to twenty-five minutes of steady grinding1 the length of time depending on the quality and quantity of the enamel1 the strength used1 etc4 ,water may or may not be mixed with the enamel during the grinding process1 as the grinder prefers4 ,if water is added the process may take a little longer but a very disagreeable noise is eliminated and the work may perhaps be slightly easier4 ,agate mortars are cleaner and so better than porcelain ones but are so much more expensive that they cannot be used for grinding large amounts4 ,for this grinding machines or weighted pestles1 such as ,cunynghame describes in his 8,art ,enameling upon ,metals10 should be used4 ,the enamel should be ground until it is about the size of fine sand1 and soft1 not gritty1 when rubbed gently between one's thumb and forefinger4 ,it should now be rinsed in clean 7the purer the better7 running water1 the enamel being thoroughly stirred up and washed1 the fine particles1 8dregs0 or 8slimes0 as they are called1 being allowed to flow away4 ,often from ten to thirty per cent of the enamel is lost in this process4 ,the remaining wet enamel powder is ready to be used4 ,it may be kept for weeks under water in a glass jar or druggist's salve box1 but in time is said to deteriorate4 ,if the enamel is to be used immediately it may be placed upon a clean copper or china palette which will be found very serviceable4 ,it should be kept constantly wet and if possible under water4 ,if1 however1 it becomes dry1 it may be washed as described above and will probably be found in good condition2 if not a slight grinding may assist matters4 ,if enamel is not ground fine enough it is apt to have pit-holes in it when fired1 and if it is not absolutely clean it is likely to have both pit-holes and black spots in it4 ,sometimes enamel is washed in nitric acid as well as water but this is generally not necessary4 ,it is very important1 however1 to use water that contains very little iron1 for iron will cause black spots in the enamel4 ,if enamel is to be kept for any length of time it should be kept either as chunks preferably or as coarsely ground powder4 ,when coarsely ground it may be kept dry in a dirt-proof jar or bottle4 ,the 8dregs0 and 8slimes0 if washed clean may be kept and used for paints in painting on enamel4 ,when enamel is bought in the form of a powder it is generally necessary to grind it finer and wash it thoroughly4 ---------------------------------------- -------------------------------- ,,chapter ,,ii ,,preparation ,,of ,,the ,,metals ,,many metals can be enameled1 but the most practical ones1 those most used in jewelry1 are gold1 silver1 copper1 and their alloys4 ,hence we will confine our descriptions to these metals4 ,whatever metal is used1 however1 must first be made chemically clean before it is 8charged0 or covered with enamel4 ,this may be done in a number of different ways1 of which the following is considered the most practical4 ,the metal1 whether gold1 silver1 or copper1 must be annealed by being heated to a red heat and allowed to cool slowly in the air4 ,when cool it will be found to be covered with a black oxide4 ,the metal must now be plunged for half a minute or more into a solution called a 8dip10 consisting of two parts sulphuric acid 7,h#b,,so#d71 two parts nitric acid 7,,hno#c71 and a slight touch of hydrochloric acid 7,h,cl72 a few drops of the latter to the gallon will suffice4 ,this dip will clean the surface of the metal and make it bright4 ,as the solution gets old it will become weak and a longer dip will be required4 ,the ordinary commercial acids are suitable for making these dips4 ,care should be taken not to inhale the fumes of the acids1 as they are quite poisonous4 ,this dip may be used cold1 but better results are obtained when it is heated to #agj;,f4 ,a convenient way to heat it is to set the jar containing the dip in a larger jar containing water and then to heat the water in the larger jar4 ,many prefer to use first a hot and then a cold dip1 rinsing the metal in clean water between the dips4 ,experience will soon teach one to tell when the metal is clean by looking at it1 and this in fact is the only satisfactory way1 as the length of time required will vary with the condition of the metals and the strength of the dip4 ,illustration3 ,,fig4 #c4 ,,enameler',s ,,spatula ,,with ,,wooden ,,handle4 ,after the dip the metal must be thoroughly rinsed in clean water and then dried in clean sawdust or hot air4 ,if rinsed in very hot water the metal will dry itself almost immediately4 ,some prefer to rinse the metal in ammonia as well as in water in order to rid it of all trace of the acid1 but this is not generally necessary4 ,if the metal is copper or gold it is now ready to be charged1 but if it is silver it must be 8fire-stained40 ,there are many other possible ways of cleaning metals1 but the above means are generally used and will doubtless be found the most convenient4 ,if small quantities only are being 8cleaned10 a copper pickle pan and a ,bunsen gas burner will suffice1 while for large quantities earthen pickle pots and large jars will be found advantageous4 ,metals if 8wriggled10 that is1 scraped or engraved all over with a graver1 are generally clean enough to be charged4 ,if silver is used it must be 8fire-stained10 or have the 8fire0 taken out of it4 ,this is done in the following manner4 ,the silver is submerged for a minute or more in a solution of four parts nitric acid and one part water1 heated to #agj;,f4 ,the acid will react on the silver1 which will become covered with a brownish scum4 ,the silver should now be rinsed in clean water and brushed with a metal brush in a solution of soap-tree bark and water4 ,this will clean the scum off the silver and make the latter bright4 ,after being rinsed in clean water1 the silver is ready to be charged with enamel4 ,sour beer1 or a solution of licorice root and water may be used instead of soap-tree bark4 ,it will be very convenient to have the metal wire brush a circular one revolving on a lathe4 ,if red enamel is to be used1 the metal should always be either wriggled or engine turned or else have some design cut sharply in it1 in order to bring out the brilliancy of the color4 ,engine turning and sharp engraving or relief in the metal background will always enhance the brilliancy and give an additional sheen to any transparent colors4 ,as the depth of the enamel layer has a great deal to do with the shade of the enamel1 different effects can be obtained1 even when only one enamel is used1 if the metal background has been cut lower in some places than in others4 ,if the silver is not 8fire-stained10 red enamel will often become maroon when fired1 and fondant and other delicate colors will become streaked or spotted4 ,if the fire-staining and dipping have not been carefully done1 the enamel is likely to chip out1 have pit-holes in it1 or contain black blotches4 ,as the acid fumes eat the flesh quite rapidly1 it is advisable to wear rubber gloves when dipping the metals4 ---------------------------------------- -------------------------------- ,,chapter ,,iii ,,charging ,,enamel is 8charged10 or put on the metal1 in the form of a watery mud1 by means of a small spatula4 ,the most convenient spatula is one made from a piece of steel wire about the size of a crochet needle and flattened at one end4 ,in fact a crochet needle itself1 flattened at one end1 or even the small blade of a penknife1 will be found quite serviceable4 ,if this spatula is mounted in a wooden handle made from a penholder it will be found very easy to handle4 ,illustration3 ,,fig4 #d4 ,,charging4 ,a small daub of very watery enamel should be taken on the end of the spatula and laid upon the metal where it is to be enameled4 ,if the surface to be enameled is very large1 a larger spatula can be used to advantage4 ,if the enamel is too watery it will not stick to the spatula while being taken from the palette1 and if it is too dry it cannot be readily transferred from the spatula to the metal4 ,when the piece has been entirely covered with enamel1 it should be held in the hand and tapped gently with the spatula4 ,if the enamel is wet enough this procedure will spread it evenly over the metal4 ,the water should now be drawn off from the enamel by means of a clean piece of cloth or blotting paper4 ,the remaining moisture will soon evaporate1 leaving the enamel perfectly dry4 ,only when perfectly dry is it in a condition to be fired4 ,care must be taken not to get the enamel on too thick1 as in that case it will chip off when fired4 ,on the other hand1 enamel shrinks considerably on being fired1 so if it is put on too thin it is apt to shrink1 leaving bare spaces of metal4 ,the proper thickness with which to charge a piece of work can only be learned by experiment1 and in most cases it is desirable to charge a piece with several thin coats rather than with one thick one4 ,in cloisonn and champlev work it is generally necessary to use at least two coats in order to bring the enamel up to the level of the metal parts4 ,originally in these kinds of enameling the idea was to have each color or shade of enamel separated by a metal wall from every other shade1 which made the charging comparatively simple4 ,now the vulgar modern taste permits several different shades side by side without partitions1 or even blended4 ,if the enamel is not too wet two distinct colors can be charged side by side without having them run into each other to any appreciable extent4 ,they may then be fired1 and they will be no more mixed in that process than they were before it4 ,a blend between two colors may be obtained by mixing two enamels together and then charging the piece with the mixture4 ,such a mixture when fired is often found to be speckled instead of a clear shade4 ,if1 after mixing1 the enamel is ground finer1 this speckled effect can sometimes be eliminated4 ,this process is by no means always satisfactory4 ,another way that two colors can be blended is as follows3 ,divide a piece to be enameled into three parts by two imaginary lines and call the parts ,a1 ,b1 and ,c4 ,now charge ,a and ,b with a thin coat of1 for instance1 blue1 and ,c with a thin coat of red1 and fire the piece4 ,then on the second charging charge ,a with blue and ,b and ,c with red4 ,when fired1 part ,b will be found intermediate between ,a and ,c1 in this case a sort of purple4 ,this purple may be made bluish or reddish1 as desired1 by using a preponderance of blue or of red enamel4 ,this preponderance can be largely regulated by the thickness of the layers or coats of each color1 although the last coat1 other things being equal1 will1 on account of its position1 exert by far the stronger influence4 ,with most transparent colors it is desirable1 though not necessary except in the case of so-called 8opals10 to use an under layer of fondant1 that is1 on the first charging1 to cover the entire surface with a thin layer of transparent white or colorless enamel1 commonly called flux or fondant4 ,this under layer of fondant is used more on gold than on silver or copper1 but in any case it will greatly enhance the brilliancy of the enamels4 ,it is of great assistance in bringing out delicate colors and especially 8opals10 for if opals are charged directly upon the stock they have a strong tendency to become opaque when fired4 ,some delicate roses and pinks if put directly upon the metal will 8fire0 black1 while over a layer of fondant they became beautiful and delicate shades4 ,where several colors are used on the same piece it is generally advantageous to use fondant for the last layer4 ,the advantage of this is that the harmony and qualities of the different colors are then not affected by the stoning and polishing1 which no matter how carefully done are bound to cut down the enamel1 and in the case of transparent colors the thinner a layer becomes the lighter it becomes4 ,any transparent color can be made lighter either by being stoned down or by being put on over a layer of fondant4 ,transparent white can easily be obtained on silver by the use of bluish and white fondants1 but it is impossible to obtain transparent white on gold or copper unless these metals are first plated with silver4 ,most enamels appear to best advantage on silver over fondant1 and when the same enamel is put on another metal it changes its hue4 ,this change of hue varies with each individual enamel and can only be learned by experiment4 ,in general1 white 7fondant7 on silver becomes pink on gold or copper1 orange becomes red1 yellow becomes orange or brown1 blue has a tendency to green and green to yellow4 ,opaque colors of course do not actually change color1 but owing to the different color of their setting they often give different effects4 ,some shades that cannot be obtained by mechanically mixing opaque colors or by layers of different transparent colors1 can be obtained by putting a layer of transparent enamel over a layer of opaque4 ,opaque white as an under layer will often give a desirable shade to a transparent enamel which is not just the color required4 ---------------------------------------- -------------------------------- ,,chapter ,,iv ,,firing ,,after enamel has been charged on a piece of metal1 it is 8fired10 that is1 heated until the enamel is fused1 after which1 on cooling1 it becomes hard4 ,it is best fired in a muffle furnace1 although with care a nice job may be done with a blowpipe1 a ,bunsen burner1 or even an alcohol lamp4 ,in case a ,bunsen burner or lamp is used1 it is well to have a metal tripod supporting a sheet of metal or wire mesh on which to set the work1 as holding it by a pair of tongs becomes very tedious4 ,illustration3 ,,fig4 #e4 ,,metal ,,tray ,,or ,,tile4 ,a muffle may be heated by electricity1 gas 7with or without an air blast71 oil1 coal1 or wood4 ,electricity or gas1 however1 is preferable1 as they are not accompanied by dirt4 ,the muffle itself1 which is simply a small oven1 is generally made of fire clay1 although both fused quartz and nickel are sometimes used4 ,a door to the muffle is not necessary1 although it is an aid to cleanliness4 ,if1 however1 a door is used it should have a hole in it large enough to allow the enameler to watch his work constantly4 ,it is very important to keep the enamel work away from the oxidizing effect of the fire2 so that any cracks that appear in a muffle must be immediately repaired4 ,it will be found very advantageous1 too1 to have the doors of the furnace on the side of it opposite to that containing the mouth of the muffle4 ,the pieces to be fired should be laid upon a tray of a size convenient to pass easily through the mouth of the muffle4 ,these trays are made preferably of sheet nickel for this metal will not scale or flake off when heated and so contaminate the enamel4 ,as these trays become quite hot it is advisable to handle them by means of a pair of long-handled tongs4 ,before placing a tray of pieces in the muffle to be fired1 it is well to leave it near the mouth of the muffle for a minute or two so that the enamel may become entirely dry before it is placed in the muffle1 for if damp the enamel will be blown off of the metal by the rapid evaporation of the water which it contains4 ,when the pieces are fully dry1 the tray may be placed in the muffle1 which should be heated to a bright red heat of about #adjj ,f4 ,with such a heat it should take from half a minute to two minutes to 8fire0 or melt the enamel4 ,the time required will vary with different enamels and can only be learned by experiment4 ,the enamel should be kept in the muffle until it begins to melt and its surface becomes fused and comparatively smooth and glossy1 when it should be removed from the furnace and allowed to cool in the air4 ,it is not necessary or even desirable to fire the enamel perfectly smooth in the first firing4 ,it generally takes at least two coats1 that is two chargings and two firings1 before a piece is ready to be stoned4 ,if1 however1 only one coat is to be used1 it should be fired as smooth as possible4 ,when the pieces cool1 the metal 7unless it is fine1 i4e41 pure1 unalloyed7 will be found covered with a black scale caused by oxidation4 ,this may be removed by simply brushing it1 which operation in most cases will clean the piece sufficiently for the second charging4 ,otherwise the piece may be 8pickled10 or cleaned with acid4 ,subsequent firings do not differ from the first one except that in the last firing the enameler should try to obtain as smooth a surface as possible4 ,after the last firing the pieces should be submerged for a minute or two in a mild pickle consisting of one part sulphuric acid and one part water4 ,this will clean off the oxide and make the metal bright4 ,if red enamel is used it is best to throw the piece into a cup of thick heavy machine oil to cool instead of letting it cool in the air4 ,this will give the red a greater brilliancy4 ,red enamel1 too1 often requires a greater heat than other colors1 although too low a heat tends to destroy the gloss on any enamel4 ,many delicate colors which are opaque when fired at a low heat1 will become opalescent and in some cases transparent if fired at a higher temperature4 ,red enamel loses its color if fired too many times1 and a large number of firings have a weakening effect on high-karat gold4 ---------------------------------------- -------------------------------- ,,chapter ,v ,,stoning ,,after a piece of enamel has been fired1 it is often found that too much enamel has been used1 that is1 that the enamel may have run over the edge of the part to be enameled1 or it may not present a smooth surface but instead consist of a series of humps1 or1 especially in the case of transparent enamels1 it may be on in such layers that the color is deepened or even lost entirely4 ,this can be remedied by what is known as 8stoning10 or filing the enamel down to a smooth surface4 ,in the case of work that is to be polished it is always considered best to overcharge the piece and then file it smooth rather than to try to 8flush0 it evenly4 ,stoning is usually done by means of emery 8stones0 or 8sticks10 which are made by mixing powdered emery with shellac and heating the same until the mixture coheres1 when it may be pressed into any shape desired by means of a flat piece of steel4 ,on cooling the stones become very hard4 ,they are generally from six to twelve inches long and from three-eighths to one inch square1 tapering at both ends to a rather blunt point4 ,when a stone wears out or loses its shape it can be remelted and remodeled4 ,the emery used in these sticks runs from ,no4 #gj to ,no4 #ahj grit4 ,illustration3 ,,fig4 #f4 ,,firing4 ,carborundum stones are often used in place of emery stones4 ,they are rather more expensive than emery stones and wear out quicker1 but they cut the work down much faster4 ,no4 #abj and ,no4 #ahj grits are the most satisfactory4 ,these stones sometimes get filled up with metal1 but in this case the metal can be eaten out with acid4 ,it is convenient when stoning to hold the piece to be stoned on a small block of wood1 on which a mold of shellac has been made into which mold the piece of work will snugly fit4 ,if the block is then set on a pivot either on a bench or bench-pin1 so that it will turn easily1 it will then be found that the stoning process has been made considerably easier4 ,a piece of hard felt or leather or just a plain piece of wood will1 however1 answer the purpose4 ,the idea is simply to hold the piece firmly and conveniently4 ,the stone should now be rubbed back and forth across the enamel as a file is used4 ,it is necessary when stoning to keep both the stone and the piece to be stoned quite wet4 ,a bowl full of water kept near by will be found very convenient for the purpose4 ,care must be taken not to make any deep scratches on the metallic parts of the piece1 as these scratches cannot easily be obliterated4 ,the stoning should be continued until the surface is smooth or level with the edges1 or until in champlev and cloisonn enamel the metal parts all show evenly1 or until the desired depths of color are obtained in the case of transparent enamels4 ,this of course can only be judged by experience1 as the colors will look much brighter when fired again4 ,when the stoning is finished it will be found that the surface of the enamel presents a rather dull or dead appearance1 which will be removed by again firing the piece4 ,before this firing1 however1 the piece should be submerged for about a minute or less in hydrofluoric acid and then brushed in clean water4 ,this may be done with any small stiff-bristled hand brush4 ,the piece will dry readily in the air1 but more quickly if first dipped in scalding hot water or brought in contact with steam4 ,it may also be dried in hot air or sawdust4 ,when dry it is ready to be fired4 ,sometimes after stoning1 low places or pit-holes are found in the enamel surface1 which may be remedied by re-charging these places with enamel and then firing the piece4 ,when only a very small amount of enamel is to be stoned off1 or when one does not want to fire the piece after the stoning1 a soft soapstone called a 8,scotch stone0 may be used to advantage4 ,if the piece to be stoned is small it is desirable to have a small wooden stick the size of a pencil with which to hold the piece steady and keep it from slipping out of its mold4 ,of course a mold is not always necessary1 but will often be found very convenient4 ,a sharp steel tool1 such as a three-cornered scraper or a slightly dull awl1 is very useful to clean out pit-holes or to chip enamel off from places where it is not desired4 ,when a large number of pieces are to be stoned1 it is advantageous to use an emery or carborundum wheel of ,no4 #ij to ,no4 #abj grit1 from two and one-half to six inches in diameter and from three-eighths to three-fourths of an inch thick1 revolving on a lathe at a low rate of speed4 ,a stream of water should be kept constantly dropping on the wheel in order to keep both the wheel and the work wet4 ,rubber cots are a great protection to the fingers1 which are gradually worn away by the stones4 ---------------------------------------- -------------------------------- ,,chapter ,,vi ,,polishing ,,after an enameled piece has been stoned and fired for the last time1 it is often desirable to give the enamel a gloss or polish additional to that which it naturally receives from the firing4 ,illustration3 ,,fig4 #g4 ,,carborundum ,,or ,,emery ,,stone4 ,if the metal used is other than fine gold or fine silver it will be black or oxidized when taken from the furnace1 in which case it should be 8pickled10 that is1 submerged for a minute or two1 until the oxidization is removed and the metal becomes bright1 in a mild 8pickle0 consisting of a warm solution of one part sulphuric acid and one part water4 ,the piece should now be rinsed in clean water1 after which it will be ready to be polished4 ,polishing is best done on a lathe with a swiftly revolving wheel1 say about #bbjj revolutions per minute4 ,a wheel of from three to six inches in diameter1 made of hard felt or wood1 is very satisfactory4 ,if the felt is thin it is often necessary to make a wooden back for it in order to keep it flat4 ,the piece to be polished should be held on a small piece of leather or felt so that the hands may not come in contact with the wheel1 in which case the skin and nails would soon be worn away4 ,rubber finger cots will serve as an additional protection4 ,the enamel surface to be polished should first be covered with wet pumice of about the consistency of mud4 ,then the pumice-covered surface should be pressed against the face of the felt or wood wheel1 and as soon as the pumice is removed by the action of the wheel more wet pumice-mud should be added so that the enamel surface may constantly be kept covered with wet pumice4 ,it is best to use the finest ground pumice obtainable1 although on rough jobs a coarse grade may be used4 ,tutty powder 7oxide of zinc7 is said to give even a better polish than fine pumice1 and is often used after a preliminary polish has been given by pumice4 ,a different wheel should be used for each polishing compound4 ,the polishing should be kept up until the enamel surface takes on the desired gloss4 ,this polishing process will cut away the metal quicker than it does the enamel1 so that any slight lines and scratches which the metal received in the stoning will be removed by the polishing4 ,care must be taken not to polish away too much of the metal1 or to cut down and destroy any metal ornaments which may be near the enameled part of the piece4 ,felt wheels being more pliable than wood wheels have a tendency to cut down the metal faster than they cut down the enamel 7the enamel being harder than the metal71 while wood wheels tend to cut down both parts equally4 ,felt wheels1 however1 are considered to give a better and quicker polish4 ,when the piece is polished sufficiently1 it should be rinsed and brushed off in clean water1 which will remove all trace of the pumice4 ,the piece is now finished as far as the enameling process is concerned1 but may1 however1 be plated1 set with stones1 engraved1 etc41 as may be desired4 ,if after the piece is polished it is found that there are a number of small pit-holes in it1 in which the pumice sticks even after the brushing1 this may be remedied by digging the pumice out with a scraper or any sharp instrument4 ,if the hole is small and the enamel transparent it will scarcely show when clean owing to the refractive power of the enamel4 ,if1 however1 the hole is so large and noticeable as to be objectionable it will have to be re-charged and re-fired4 ,in such a case it is often possible after the first firing to stone it smooth with a ,scotch stone or by polishing and thus avoid another firing4 ---------------------------------------- -------------------------------- ,,chapter ,,vii ,,foils--,,paillons--,,glitter ,,enamel--,,dull ,,finish--,,plique--,,jour ,,foils and paillons are generally made of fine gold or fine silver leaf4 ,silver foils are used on copper and gold work in order to obtain better enamel effects1 for most transparent colors are shown to best advantage over silver4 ,gold foils are sometimes used on copper for similar reasons4 ,the metal is first charged and fired with a coat of any enamel1 preferably a 8hard running0 white1 that is1 one that it takes a comparatively high temperature to melt4 ,the foil is then stuck to the enamel by means of gum arabic1 tragacanth or1 in fact1 some kinds of common mucilage will answer the purpose4 ,as ,cunynghame says1 8,what is wanted is a good tenacious gum1 which disappears as completely as possible when heated and leaves no carbonaceous residue to spoil the enamel40 ,the foil should be cut so that it will exactly fit the enamel surface1 and cover it entirely so that none of the white enamel will show on the finished piece4 ,if the foil is stamped with some design it will add greatly to the brilliancy of the enamel afterwards applied1 and if it is pierced with a number of small holes through which the fumes of the gum can escape1 it will stick smoothly to the enamel4 ,after the foil has been put upon the enamel1 the piece should be fired until the foil adheres strongly and smoothly to the enamel1 when it is ready for the next charging4 ,from this point on the process does not differ from that employed when charging directly upon the metal4 7,see chapter on charging47 ,paillons are simply small bits of foil cut into dainty and artistic shapes such as stars1 fleurs-de-lis1 etc4 ,they are applied by means of gum1 as in the case of foils1 on the surface of the last or upper layer of colored enamel1 after it has been fired1 and the piece is again fired1 making the paillons adhere to the enamel4 ,the piece is then charged all over with a coat of fondant and fired1 after which it is ready to be stoned and polished1 if desired4 ,illustration3 ,,fig4 #h4 ,,stoning4 ,glitter enamel1 called by the ,germans 8flimmer10 is simply ground up goldstone 7,aventurin7 mixed with an ordinary enamel in equal proportions or two parts of goldstone to one of enamel4 ,some very striking effects can be produced with this mixture1 which should be stoned to bring out the brilliancy of the goldstone4 ,the best effects are obtained when some dark opaque enamel is used4 ,to obtain the so-called dead or dull finish on enameled goods1 it is only necessary to submerge the piece for two or three minutes in a solution of hydrofluoric acid4 ,this will 8etch0 the enamel leaving the surface dull like ground glass4 ,when the piece is etched evenly all over1 it should be removed from the acid and washed and dried4 ,the etching will only take a few minutes if the acid is strong1 and will be done much more evenly if a mixture of hydrofluoric acid and ammonium carbonate1 known as white acid1 is used4 ,if only part of the surface is to be dulled or etched1 the part that is not to be etched should be covered with shellac1 or a mixture of three parts beeswax and one part ,burgundy pitch1 and allowed to dry before the piece is put in the acid4 ,the acid must be kept either in lead or wax bottles1 as it eats glass very rapidly4 ,its fumes are very dangerous and destroy human tissues4 ,if for some reason a piece has been enameled wrong1 so that it is desirable to take the enamel off the metal1 this can best be done by leaving the piece for a few hours in a solution of hydrofluoric acid which will eat the enamel1 so that it can easily be brushed off the metal1 leaving it bright4 ,plique--jour enamel may be done in several ways4 ,the simplest is to lay the filigree work upon a piece of mica or fire clay and charge with enamel1 as if the mica or fire clay were the background and the filigree work the sides of the piece4 ,the process continues the same as in ordinary enameling1 except that just before the last firing the mica or fire clay should be removed4 ,copper or silver foil may be used instead of mica1 but in this case the filigree work must be either of gold or platinum1 for the copper or silver foil can only be removed by being dissolved in nitric acid4 ,the most difficult way is to mix a little gum arabic or gum tragacanth with very finely ground enamel and charge a layer on the inner sides of the wires which make up the filigree work4 ,the gums will hold the enamel in place after it is dried4 ,when the piece has been fired1 another layer of enamel should be charged and so on1 until by degrees the entire space between the wires has been filled up4 ,this process is tedious and requires much skill and care1 but gives very satisfactory results4 ---------------------------------------- -------------------------------- ,,chapter ,,viii ,,enamel ,,painting ,,enamel painting is usually done on a background of opaque white enamel1 although other opaque colors are sometimes used4 ,the metal must be prepared in the regular manner1 and one or two coats of enamel charged and fired1 the last coat being fired to as perfect smoothness as possible4 ,instead of flushing the enamel smooth it is often advisable to stone and fire it1 by which processes a smoother surface is obtained4 ,after this last firing1 the black flakes of metallic oxide which will be found on the metal should be brushed away1 leaving the piece clean and ready to be painted4 ,it is desirable not to have too thick a layer of enamel1 as in that case it is apt to chip off in some of the later firings4 ,if1 on the other hand1 the enamel layer is thin1 it is quite difficult to get it smooth4 ,illustration3 ,,fig4 #i4 ,,copper ,,pickle ,,pan4 ,any picture desired may now be painted on the enamel surface1 either with ordinary china paints or finely ground enamel 8slimes0 mixed with oil of cloves or oil of lavender4 ,this painting may be done with a small camel's-hair brush and when finished should be fired until the enamel fuses4 ,the piece should be allowed to cool slowly and when cool should be charged with a coat or two of clear fondant which1 after being fired1 may or may not be stoned and polished1 as the artist sees fit4 ,if the painting requires it1 it may be touched up and fired several times before being charged with the fondant1 but the fewer times a piece is fired the less chance there is for accidents which may prove fatal to the work of art4 ,if the metal used is very thin1 it will be necessary to enamel it on the back as well as on the front1 for a thin piece of metal which is enameled on one side only will warp out of shape1 but if enameled on both sides will keep its shape perfectly4 ,of course the enamel on the back may be of any color and need not be finished carefully1 as it is there for use not ornament4 ,an enamel painting must be fired with great care4 ,first it must be warmed by degrees before put into the muffle1 so that the oil may have a chance to evaporate4 ,it should then be placed partly in the muffle and not put way in and should not be heated to a red heat until the residues of the oils shall have burnt away4 ,if too hot a muffle is used1 or if the piece is fired too long1 the painting will appear blurred and faint4 ,if the painting appears blistered after firing1 it is due to the fact that the oils used contained too much carbonaceous residue4 ,the fondant used on an enamel painting should be very finely ground1 much more so than for ordinary work1 and the first layer of fondant should not be fired to smoothness but only until it just begins to flow1 as was the case with the painting itself4 ,the last layer of fondant should of course be fired as smooth as possible4 99 99 99 99 99 ,if a large number of pieces are to be painted with the same design1 there are a number of mechanical means that can be used to take the place of free-hand painting4 ,we will outline one of these processes1 which is as follows4 ,etch a copper plate with the outline of the design that is to be painted on the enamel4 ,the etching on the copper plate must be a positive1 not a negative2 that is1 the design must appear on the plate as it is to appear on the enamel and not reversed as in ordinary etching4 ,the design must also be exactly the same size as the one to appear on the enamel4 ,the lines in the etching should now be filled with finely ground enamel paints mixed with oil of cloves or some such medium4 ,it is best to use paint of the color that is to predominate in the picture1 although in some cases it will be found that black will give the best working outline4 ,when the lines of the etching are filled with the paint1 the plate should be scraped smooth so that no paint remains on it except in the etched lines4 ,the plate should now be pressed against a piece of thin1 smooth1 sheet rubber1 to which the paint will stick in preference to the copper plate1 thus transferring the design to the sheet of rubber1 where it appears reversed4 ,the rubber with the design side down is now pressed upon the smooth surface of the white enamel1 which should be prepared in the same way as it would be prepared for regular painting4 ,the design is thus transferred from the rubber to the enamel surface1 where it appears again positive4 ,the enamel surface now has on it the outline of the design either in black or in color as the case may be4 ,from this point on1 the process is the same as in regular hand painting on enamel1 but as the outline has been blocked in1 the work is considerably easier4 ,a speed and uniformity are obtained by this process which it is difficult to equal with free-hand work4 ,another process whereby a number of similar designs can be easily executed is by decalcomania4 ,decalcomania pictures are made in ,germany and can be obtained through any artists' supply house4 ,in this case the white enamel background is obtained in the usual manner1 after which a decalcomania picture is transferred to the enamel surface4 ,the enamel is first covered with a very thin layer of size or gum as in the case of foils4 ,when the size becomes sticky1 the decalcomania picture should be placed face downwards on the enamel4 ,the paper on the back of the picture should now be wet with a sponge until it becomes loose1 when it should be removed and the remaining scum washed off with plenty of clean water4 ,the piece after being dried thoroughly is ready to be fired4 ,the rest of the process is the same as in regular painted enamel work4 ,great care must be taken in firing the decalcomania work4 ---------------------------------------- -------------------------------- ,,chapter ,,ix ,,photographs ,,on ,,enamel ,,there are several methods by which photographs may be reproduced upon enamel4 ,however1 since they are rather difficult1 we will explain only one method1 and for the other processes will refer the student to ,dr4 ,paul ,liesegang's treatise on photographing on enamel1 porcelain1 and glass1 which is printed in ,german4 ,in the first place only the best quality of mirror glass should be used for the plates1 as it is essential that they should be perfectly smooth and without blemishes4 ,the glass should then be cut the same size as the negative plate which is to be used later4 ,the glass plate must be made perfectly clean1 which is best done by placing it in a mild sulphuric acid bath for about ten minutes and then washing it well with clean water4 ,it should be dried with a clean cloth or tissue paper1 after which it may be wrapped in clean dry tissue paper and kept in a dry place until needed4 ,illustration3 ,,fig4 #aj4 ,,polishing4 ,out of the many receipts for preparing the sensitive solution1 we will give only the two most generally found satisfactory4 ,these are as follows3 7#a7 ,dissolve one-half ounce of ammonium bichromate in five ounces of clean water4 ,in another glass dissolve one ounce of grape sugar and one ounce of gum arabic in five ounces of clean water4 ,when the solutions are completely dissolved1 they should be mixed together1 stirred considerably1 and filtered several times4 7#b7 ,dissolve one-half ounce of ,le ,page's best fish glue and two ounces of grape sugar in five ounces of clean water4 ,in another glass dissolve one-half ounce of ammonium bichromate in five ounces of clean water4 ,when both are perfectly dissolved1 pour the two solutions together1 and stir them well1 after which the mixture should be filtered several times4 ,these solutions should be prepared in the dark room and should not be kept more than a day or two1 as both light and time will destroy their power4 ,they should be kept in the dark room in a glass-stoppered bottle4 ,the sensitive solution1 however it may have been made1 should be poured over the clean1 dry glass plate already described1 as soon as possible after it is made4 ,this is done in exactly the same manner that photographers prepare wet plates4 ,the waste solution running off the glass plate should be filtered and saved as it may be used again4 ,this pouring must be done in the dark room and dust must be carefully avoided4 ,the wet plates should now be dried on an iron frame covered with paper and heated from underneath by a small gas or alcohol lamp4 ,they should not be heated hotter than the hand can comfortably bear4 ,when they are perfectly dry1 they should be left in the dark room in a dry1 warm place1 free from dust and should be used the same day4 ,the next step is to place the negative that is to be reproduced in a copying frame with the glass side out4 ,it should be perfectly clean and free from dust4 ,the sensitive plate is then put in the frame with the sensitive side towards the negative4 ,any friction between the plates must be avoided4 ,this1 of course1 is done in the dark room4 ,the plates are now exposed in the sunlight from half a minute to a minute4 ,if exposed in the shade it will take from five to ten minutes4 ,if the weather is very damp it is advisable to use a previously warmed sensitive plate and negative for exposure to the light1 since damp weather injures the sensitiveness of the plate4 ,also it is well to avoid any sudden change of temperature during the exposure4 ,in the winter it is best to make the exposure in a warm room having about the same temperature as the dark room4 ,after the exposure is finished1 the copying frame should be carried to the dark room1 where the next operation must take place4 ,first1 the exposed sensitive plate should be taken carefully out of the copying frame and placed on a piece of paper with the sensitive side upward4 ,the picture will not as yet be discernible upon it4 ,now place a quantity of black or brown dry enamel paint on the plate and gently scatter this powder over it by means of a soft1 clean1 dry brush1 which should be kept for this purpose only4 ,then brush the enamel powder back into its bottle4 ,it is very essential that no dust shall get into it4 ,after five or ten minutes repeat the powdering and so on two or three times until the picture is clearly developed4 ,if the sensitive plate has been underexposed1 the picture will develop rather quickly at the first powdering4 ,this will generally give blurred reproductions1 and it is scarcely worth while to bother longer with that plate4 ,the only thing to do is to make another exposure4 ,with a well exposed plate1 the picture should develop slowly1 that is1 not before the second or third powdering4 ,if the weather has been exceedingly dry1 it is advisable to breathe gently on the exposed sensitive plate before beginning the powdering4 ,if1 on the other hand1 the weather has been damp1 the plate should be warmed slightly before powdering4 ,illustration3 ,,fig4 #aa4 ,,pickle ,,pot ,,or ,,dip ,,basket4 ,when the picture shows clearly1 brush all the surplus powder carefully from the plate1 which is now ready to be treated with collodion4 ,add about twenty drops of castor oil to a pint of #b per cent collodion solution and mix it thoroughly4 ,this mixture1 which must be free from air bubbles1 should now be poured over the powdered plate4 ,the waste collodion which runs off the plate is contaminated by traces of the enamel paint and cannot be used again4 ,after the collodion has hardened1 cut around the edges of the plate with a knife and then place the plate with the collodion side upward in a dish containing a weak solution of caustic potash 7half an ounce of caustic potash dissolved in a quart of water74 ,this solution will remove all the chromium which has served its purpose4 ,leave the plate in this solution until the first appearing yellow coloring has disappeared1 and then place it with the collodion side upwards in a basin with slowly running water1 which will in about an hour wash away all the chromium and potassium salts4 ,the plate should then be placed in a dish of clean water to which a few drops of nitric acid have been added1 not more than enough1 however1 to give the water a slight sour taste4 ,the plate may remain over night in this solution without harm to the picture1 although a couple of minutes will be found entirely sufficient if one is in a hurry4 ,next1 the plate should be placed in a large basin of clean water with the collodion side downwards4 ,if the collodion film has previously been cut properly around the edges1 it will soon separate from the plate1 which may be removed1 leaving the collodion film floating in the water4 ,meanwhile1 the enameled metal plate1 which has been prepared exactly the same as is done for enamel painting1 should be cleaned with a soda solution to free it from all grease4 ,it should now be placed upon a wire support and carefully brought under the floating film which can be deposited gently on the enameled surface by means of a soft brush4 ,the plate should then be taken slowly out of the water and the overlapping parts of the film should be turned under the edges of the plate1 after which it should be put on a piece of white blotting paper to dry4 ,if any air bubbles appear under the film1 they should be brushed very gently with a soft1 wet brush towards the edge of the plate1 where they will do no harm4 ,if this does not prove successful1 the bubbles may be opened with a needle1 after which the air may be pressed out with a wad of soft paper4 ,when the plate with the collodion film on it is perfectly dry1 the collodion should be removed by placing the plate in a dish of concentrated sulphuric acid4 ,within a few minutes the collodion will entirely dissolve4 ,when this has taken place1 a brownish ring will appear around the plate1 whereupon the plate should be removed at once and put in a large basin of clean water4 ,finally1 it should be submerged in a weak solution of ammonia 7one ounce of ammonia to a quart of water71 which will neutralize the last traces of the acid1 after which it should be left on a piece of blotting paper to dry4 ,the picture may now be retouched just as photographers retouch ordinary photographs1 only the same enamel paint should be used that was used in the powdering process4 ,after the retouching1 the plate may be fired in a muffle1 just as is an ordinary enamel painting1 and then covered with a layer of fondant4 ,the finished photograph may1 however1 be painted with enamel paints if the enameler desires to make a colored photograph4 ---------------------------------------- -------------------------------- ,,where ,,enamelers' ,,supplies ,,can ,,be ,,obtained ,,enamels1 ,,howard ,m4 ,,chapin1 #hd ,keene ,st41 ,providence4 ,,enamel ,,paints1 ,,wadsworth1 ,,howland ,,co41 ,boston4 ,,furnaces1 ,,simplex ,,tool ,,and ,,supply ,,co41 ,boston4 ,,muffles1 ,,simplex ,,tool ,,and ,,supply ,,co41 ,boston4 ,,grinding ,,machines1 ,,abbe ,,engineering ,,co41 ,new ,york4 ,,carborundum1 ,,carborundum ,,co41 ,niagara ,falls4 ,,wax ,,bottles1 ,,baker ,,adamson ,,co41 ,easton1 ,pa4 ,,acids1 ,,pumice1 ,,etc41 ,,geo4 ,l4 ,,claflin ,,co41 ,providence4 ,,tiles1 ,,beckley ,,perforating ,,co41 ,garwood1 ,n4,j4 ,,felt1 ,,brown ,,bros4 ,,co41 ,providence4 ,,paillons1 ,,howard ,m4 ,,chapin1 #hd ,keene ,st41 ,providence4 ,,decalcomania ,,films1 ,,malden ,,china ,,co41 ,malden1 ,mass4 ,,mortars ,,and ,,chemical ,,glassware1 ,,geo4 ,l4 ,,claflin ,,co41 ,providence4 ---------------------------------------- -------------------------------- ,transcriber's ,notes3 ,missing or obscured punctuation was silently corrected4 ,typographical errors were silently corrected4 ,inconsistent spelling and hyphenation were made consistent only when a predominant form was found in this book4 ,text that was in italics is enclosed by underscores 7italics74 ,the use of a caret 77 before a letter1 or letters1 shows that the following letter was intended to be a superscript1 as in ,st ,bartholomew or #ajth ,century4 4it ,the use of an underscore 77 before a letter1 or letters1 show that the following letter was intended to be a subscript1 as in ,,hno#c 7nitric acid74 ,if there is more than one letter in a superscript or subscript they are enclosed in brackets--4 s