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To Coat Figures with Copper

When plaster busts or figures are wanted in copper, the usual way is to prepare the figure moisten it thoroughly; this is put into a me- with wax (sce No. 3688) and to coat it over tallic vessel, which is placed in a hot bath of with a thin deposit of copper, letting the copboiling water. When the glue falls into a per remain. Some operators, when it can be fluid state, 3 pounds of molasses are added, done, remove the plaster and wash over the and the whole is well mixed by stirring. inside with an alloy of tin and lead melted. Suppose, now, that the mould of a small bust In this case the copper must previously be is wanted, a cylindrical vessel is chosen so cleaned by washing first in a solution of potdeep that the bust may stand in it an inch or ash, and then with chloride of zinc. The latter mode will cause the alloy to adhere to the cold, will not absorb the wax or tallow; hence copper and give it strength. In either of it may be recovered again. The sulphate of these cases the deposit must not be very thick, copper possesses so penetrating a quality that or it will throw the figures out of proportion, if the slightest imperfection occurs in the such as the features of a bust, etc. Any saturation of the mould by wax, the solution slight roughness of deposit may be easily will penetrate through it, and the copper smoothed down by means of fine emery or glass paper. (See No. 1935.) 3688. To Prepare a Plaster Cast for Electrotyping. First dry the plaster cast in the oven thoroughly, then get equal parts of bees' wax and common resin, melt them will be deposited upon the face of the object adhering to the plaster, giving to the metal a rough, matted appearance, and seriously injuring it.