Glue, gelatine, animal charcoal, phosphorous, cements, pastes and mucilages

by F. Dawidowsky

e. Orange colors are produced by an addition of solution of chrysaniline generally sold under the name of Victoria orange, and violet by adding aniline violet. For these, as well as for the solution colored with fuchsine, the plates must not be rubbed with oil, as even the smallest trace of the latter discolors these colors in drying, or at least the veneers will show spots without color.

3. Pouring the colored solutions of glue upon the plates. For imitations of marble and enamel, the glass plates, after rubbing with oil, are placed, rubbed surface up, in a perfectly level position. The proper portion of the white ground-mass, after becoming somewhat thickish, is then poured upon the plates, and the gaps left free in pouring filled in and smoothed with a knife-shaped tool of horn or bone. Upon this white ground the respective colored glue solutions are then poured in a zigzag form, and in conformity with the desired design, drawn through the ground-mass with a glass rod. If several differently colored glue solutions are to be applied, as given, for instance, under 2f, they should be poured in quick succession, so that the succeeding color runs into the preceding, and a white strip or spot remains between each color. The whole is then intermingled by the glass rod, according to the design. If the latter is to have sharply defined lines and spots, the respective colored solution of glue is used somewhat thicker, but if, on the other hand, the design is to be somewhat blended, the glue solutions are used somewhat warmer, and consequently more thinly fluid. After solidification of the glue solutions the plates are placed in a cool room for two or three hours.

Imitations of malachite are prepared in a similar manner. Four glue solutions of different shades of green from the darkest to the lightest tint are prepared and poured upon a slightly greenish ground, so as to imitate the characteristic curves and veins of malachite, which are then further traced with a comb with teeth standing at unequal distances from each other.

The glass plates set aside to be used for imitation of mother-of-pearl are now taken in hand. The solutions of glue are kept warm over a water bath and thoroughly stirred every time before pouring them upon the plates. The formation of a film on the surface of the glue solution must be strictly avoided.

For pouring out the solutions it is best to use a porcelain vessel provided with a spout and handle, and having a capacity of about 6¾ fluidounces. The portion of glue solution required for each plate (1¾ flu. oz.) is then measured into one of the porcelain vessels, and, after standing a short time, poured upon the plate and uniformly distributed. The production of a mother-of-pearl design requires some skill and practice. A comb with teeth set ½ inch apart is used. It is held in a somewhat oblique position, the teeth are gently pressed upon the glass plate, and, with frequent turnings of the comb at a right angle, cycloidal motions executed. The operation is carried on from the front to the back edge of the glass plate, and when the glue begins to thicken on the edges, continued at the softer places until the desired design is produced, care being had not to touch places which have already acquired a certain degree of solidity, as this would mar the pattern. After treating all the plates in this manner, they are set aside in a cool room for two or three hours.

4. Transferring the layer of glue to a layer of gelatine. For each dozen of veneers soak 2½ ozs. of gelatine, and then melt them in a water-bath, and after adding glycerine equal to 10 per cent. of the dry gelatine, let the mixture settle.

The glass plates treated with rouge and Spanish chalk are now placed in a perfectly level position, and after pouring 5½ fl. ozs. of gelatine solution upon each of them, the gaps left in pouring are filled in and smoothed with the glass rod. The front edge of a plate covered with a colored layer of glue is now, glue side down, placed upon the front edge of a gelatine plate, while the back edge of the former is gradually lowered until the glue plate lies firmly upon the gelatine plate.

It may here be remarked that the gelatine solution must only be allowed to cool off sufficiently to prevent the melting of the glue plate on touching it. If it is cooler the veneers will have blisters. It must further be looked to that, before placing the first plate upon the gelatine plate, no gelatine escapes, and that any excess only runs off after the back edge of the glue plate touches that of the gelatine plate.

The plates are now allowed to rest quietly until the gelatine is congealed, when they are removed to a cool place where they remain five or six hours.

Imitations of mother-of-pearl are treated in the same manner with the exception that the gelatine solution is colored with the same coloring matter as the glue solution. For colorless or yellowish veneers the gelatine solution is not colored.