Howard M. Chapin

“ Plique-à-jour enamel is similar to cloisonné except that the wires are soldered to each other without any background, thus forming a sort of filigree, the spaces within which, when filled with enamel, somewhat resemble a stained-glass window.
In enamel painting a picture is painted on the enamel. Usually white opaque enamel is used for the background, and the painting is executed with finely ground enamel or china paints, after which it is covered with a layer of transparent enamel which serves as a protection for the painting. ”

“ Where several colors are used on the same piece it is generally advantageous to use fondant for the last layer. The advantage of this is that the harmony and qualities of the different colors are then not affected by the stoning and polishing, which no matter how carefully done are bound to cut down the enamel, and in the case of transparent colors the thinner a layer becomes the lighter it becomes.
Any transparent color can be made lighter either by being stoned down or by being put on over a layer of fondant. ”

“ Silver foils are used on copper and gold work in order to obtain better enamel effects, for most transparent colors are shown to best advantage over silver. Gold foils are sometimes used on copper for similar reasons.
The metal is first charged and fired with a coat of any enamel, preferably a “hard running” white, that is, one that it takes a comparatively high temperature to melt. The foil is then stuck to the enamel by means of gum arabic, tragacanth or, in fact, some kinds of common mucilage will answer the purpose. ”

“ Sometimes after stoning, low places or pit-holes are found in the enamel surface, which may be remedied by re-charging these places with enamel and then firing the piece.
When only a very small amount of enamel is to be stoned off, or when one does not want to fire the piece after the stoning, a soft soapstone called a “Scotch stone” may be used to advantage.
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 mold. ”

“ If the metal used is very thin, it will be necessary to enamel it on the back as well as on the front, for a thin piece of metal which is enameled on one side only will warp out of shape, but if enameled on both sides will keep its shape perfectly. Of course the enamel on the back may be of any color and need not be finished carefully, as it is there for use not ornament.
An enamel painting must be fired with great care. First it must be warmed by degrees before put into the muffle, so that the oil may have a chance to evaporate. ”

“ If for some reason a piece has been enameled wrong, so that it is desirable to take the enamel off the metal, this can best be done by leaving the piece for a few hours in a solution of hydrofluoric acid which will eat the enamel, so that it can easily be brushed off the metal, leaving it bright. ”

“ A sharp steel tool, such as a three-cornered scraper or a slightly dull awl, is very useful to clean out pit-holes or to chip enamel off from places where it is not desired.
When a large number of pieces are to be stoned, it is advantageous to use an emery or carborundum wheel of No. 90 to No. 120 grit, from two and one-half to six inches in diameter and from three-eighths to three-fourths of an inch thick, revolving on a lathe at a low rate of speed. A stream of water should be kept constantly dropping on the wheel in order to keep both the wheel and the work wet. ”

“ Many delicate colors which are opaque when fired at a low heat, will become opalescent and in some cases transparent if fired at a higher temperature. Red enamel loses its color if fired too many times, and a large number of firings have a weakening effect on high-karat gold. ”

“ This can be remedied by what is known as “stoning,” or filing the enamel down to a smooth surface. 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 “flush” it evenly.
30Stoning is usually done by means of emery “stones” or “sticks,” which are made by mixing powdered emery with shellac and heating the same until the mixture coheres, when it may be pressed into any shape desired by means of a flat piece of steel. On cooling the stones become very hard. ”

“ We will confine our attention to what is known as hard enamel in contradistinction to japans, lacquers, and enamel paints, which are often called soft enamels. Hard enamels are compounds of glass with different metallic oxides which produce the different colors. ”

“ Care must be taken not to get the enamel on too thick, as in that case it will chip off when fired. On the other hand, enamel shrinks considerably on being fired, so if it is put on too thin it is apt to shrink, leaving bare spaces of metal. ”

“ If the silver is not “fire-stained,” red enamel will often become maroon when fired, and fondant and other delicate colors will become streaked or spotted. If the fire-staining and dipping have not been carefully done, the enamel is likely to chip out, have pit-holes in it, or contain black blotches.
As the acid fumes eat the flesh quite rapidly, it is advisable to wear rubber gloves when dipping the metals.
14 CHAPTER III
CHARGING Enamel is “charged,” or put on the metal, in the form of a watery mud, by means of a small spatula. ”

“ Then the pumice-covered surface should be pressed against the face of the felt or wood wheel, and as 39soon 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 pumice.
It is best to use the finest ground pumice obtainable, although on rough jobs a coarse grade may be used. Tutty powder (oxide of zinc) is said to give even a better polish than fine pumice, and is often used after a preliminary polish has been given by pumice. A different wheel should be used for each polishing compound. ”

“ This painting may be done with a small camel’s-hair brush and when finished should be fired until the enamel fuses. The piece should be allowed to cool slowly and when cool should be charged with a coat or two of clear fondant which, after being fired, may or may not be stoned and polished, as the artist sees fit. If the painting 52requires it, it may be touched up and fired several times before being charged with the fondant, but the fewer times a piece is fired the less chance there is for accidents which may prove fatal to the work of art. ”

“ They fill the gap between glass and china, the transparent fondants being to the layman indistinguishable from glass, while the opaque whites may be easily mistaken for china, and the countless other varieties form a chain of xscarcely perceptible gradations from one extreme to the other. ”

“ These chunks of enamel may be readily broken up by a hammer, and if they are first wrapped in a piece of cloth the small particles will not fly about and get into one’s eye, and no enamel will be lost. ”

“ If only part of the surface is to be dulled or etched, the part that is not to be etched should be covered with shellac, or a mixture of three parts beeswax and one part Burgundy pitch, and allowed to dry before the piece is put in the acid. The acid must be kept either in lead or wax bottles, as it eats glass very rapidly. Its 48fumes are very dangerous and destroy human tissues. ”

“ If the weather is 63very damp it is advisable to use a previously warmed sensitive plate and negative for exposure to the light, since damp weather injures the sensitiveness of the plate. Also it is well to avoid any sudden change of temperature during the exposure. In the winter it is best to make the exposure in a warm room having about the same temperature as the dark room. ”

“ Many prefer to use first a hot and then a cold dip, rinsing the metal in clean water 10between the dips. Experience will soon teach one to tell when the metal is clean by looking at it, and this in fact is the only satisfactory way, as the length of time required will vary with the condition of the metals and the strength of the dip. ”

“ The waste solution running off the glass plate should be filtered and saved as it may be used again. This pouring must be done in the dark room and dust must be carefully 62avoided. The wet plates should now be dried on an iron frame covered with paper and heated from underneath by a small gas or alcohol lamp. They should not be heated hotter than the hand can comfortably bear. When they are perfectly dry, they should be left in the dark room in a dry, warm place, free from dust and should be used the same day. ”

“ 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 soft, clean, dry brush, which should be kept for this 64purpose only. Then brush the enamel powder back into its bottle. It is very essential that no dust shall get into it. After five or ten minutes repeat the powdering and so on two or three times until the picture is clearly developed. ”

“ They are generally from six to twelve inches long and from three-eighths to one inch square, tapering at both ends to a rather blunt point. When a stone wears out or loses its shape it can be remelted and remodeled. The emery used in these sticks runs from No. ”