(a) Take lampblack, about a thimbleful, and put it on a flat stone or smooth slate; add four or five spots of gold size, and well mix with a palette knife, making the whole about as thick as putty; well mix. The less gold size there is the better, so that the lampblack just sticks together; if too much gold size be added, the effect will be a bright black and not a dead black. Now add turpentine, about twice its own volume, to the whole, mix with a camel-hair brush, and apply to the brasswork.
(6) Dip the article bright in aquafortis; rinse the acid off with clean water, and place it in the following mixture until it turns black: - Hydrochloric acid, 12 lb.; sulphate of iron, 1 lb.; and pure white arsenic, 1 lb. Then take out, rinse in clean water, dry in sawdust, polish with black-lead, and then lacquer with green lacquer.
(c) 1 part oxide of iron, 1 part white arsenic, 12 parts hydrochloric acid. Clean the brass well to get rid of lacquer or grease, and apply with a brush until the desired colour is obtained. Stop the process by oiling well, when it may be varnished or clear lacquered.
Steep the medal or figure in a strong solution of common salt or sugar, or sal ammoniac, for a few days, wash in water and allow to dry slowly, or suspend over a vessel containing a small quantity of bleaching powder, and cover over - the length of time it is allowed to remain will determine the depth of the colour.
Four or five drops of nitric acid to a wine-glassful of water, and allowed to dry, and when dry impart to the object a gradual and equal heat; the surface will be darkened in proportion to the heat applied.
Wash the surface of the object over with a little sulphide of ammonium (dilute), and dry at a gentle heat; polish with a hard brush afterwards.
To one pint of methylated finish add 4 oz. of gum shellac and 1/2 oz. gum benzoin; put the bottle in a warm place, shaking it occasionally. When the gum is dissolved, let it stand in a cool place two or three days to settle, then gently pour off the clear into another bottle, cork it well, and keep it for finest work. The sediment left in the first bottle, by adding a sufficient quantity of spirit to make it workable, will do for the first coat or coarser work when strained through a fine cloth. Next get } lb. of finely-ground bronze green, the shade may be varied by using a little lampblack, red ochre, or yellow ochre; let the iron be clean and smooth, then take as much varnish as may be required, and add to the green colour in sufficient quantity; slightly warm the article to be bronzed, and with a soft; brush, lay a thick coat on it. When that is dry, if necessary lay another coat on, and repeat until well covered. Take a small quantity of the varnish and touch the prominent parts with it; before it is dry, with a dry pencil lay on a small quantity of gold powder.
Varnish over all.
Lay the figure over with isinglass size, until it holds out, or without any part of its surface becoming dry; then, with a brush, such as is termed by painters a sash tool, go over the whole, taking care to remove, while it is yet soft, any of the size that may lodge on the delicate parts of the figure. When it is dry, take a little very thin oil gold size, and with as much as just damps the brush, go over the figure with it, allowing no more to remain than causes it to shine. Set it aside in a dry place free from smoke, and in forty-eight hours the figure is prepared to receive the bronze.
After having touched over the whole figure with the bronze powder, let it stand another day, and then with a soft dry brush rub off all the loose powder, particularly from the points or more prominent parts of the figure.
The wood is first covered with a uniform coating of glue, or of drying oil, and when nearly dry the bronze powder, contained in a small bag, is dusted over it. The surface of the object is afterwards rubbed with a piece of moist rag. Or the bronze powder may be previously mixed with the drying oil, and applied with a brush.