3577. Grecian Gilding

3577.    Grecian Gilding. Dissolve equal parts of sal-ammoniac and corrosive sublimate in nitric acid, and a solution of gold is to be made with the above mixture as a solvent; after slight concentration, the liquid is applied to the surface of silver, which immediately becomes black, but, on being heated, exhibits a rich gilded surface.

3578. Japanners' Gilding

3578.    Japanners' Gilding. The surface is covered with oil size thinned with spirits of turpentine, and gold in powder (see No. 2517 (To Pulverize Gold and Silver Leaf)) is gently dabbed on with a puff of wash-leather. This gives the appearance of frosted gold. A coating of varnish is next given, followed by a gentle heat in the stove.

3579. Leaf Gilding

3579. Leaf Gilding. This term is commonly applied to the gilding of paper, vellum, etc., by applying leaf gold to the surface previously prepared with a coating of gum water, size, or white of egg. It may be burnished with an agate.

3580. To Make Oil Gold Size

3580.    To Make Oil Gold Size. This is usually made from the sediment which collects at the bottom of the pot or dish in which painters wash their brushes, thoroughly ground and stained.

3581. Oil Gilding

3581.    Oil Gilding. The surface is prepared or primed with a coat of white lead in drying oil; then follow 2, 3, or 4 coats of calcined white lead ground in linseed oil and turpentine, with an interval of at least 24 hours between each coat, which must be carefully smoothed off with pumice-stone or shave grass. The gold size (see No. 3580 (To Make Oil Gold Size)) is next applied. "When the gold size coat is sufficiently dry, the gold leaf is applied and pressed on with a wad or soft brush. After a few days for hardening, a coat of spirit varnish is applied, and the surface passed cautiously and evenly over a chafing dish of charcoal. For indoor work, it is finished off with a coat of pale oil varnish.

3582. To Gild Polished Metal

3582. To Gild Polished Metal. Polished silver, copper, brass, etc., may be gilded by the direct application of gold leaf to the surface heated to a bluish tint, pressing it on gently and carefully with the burnisher. This process is repeated until the proper thickness and tone is attained. Then it is polished with the burnisher and colored at the stove.

3583. Gold Tracing on Metal

3583. Gold Tracing on Metal. Writing or any device in gold may be made on polished steel or iron, by tracing on the surface with a camel-hair pencil, using an ethereal solution of gold. The ether evaporating leaves a coating of gold, which may then be polished. (See No. 3585 (Ethereal Solution of Gold for Gilding on Steel).)

3584. Water Gilding

3584.      Water Gilding. This process involves several distinct operations, and can only be performed successfully by those who have learned the art practically.

3585. Ethereal Solution of Gold for Gilding on Steel

3585.    Ethereal Solution of Gold for Gilding on Steel. This process answers equally well for either gold or platina. Dissolve any quantity of gold or platina in nitro-muriatic acid (aqua regia), until no further effervescence is occasioned by the application of heat. (See No. 3588.) Evaporate the solution of gold or platina, thus formed, to dryness, in a gentle heat (it will then be freed from all excess of acid, which is essential), and redissolve the dry mass in as little water as possible; next take a separating funnel or pipette (see No. 0000), fill it about one-fourth with the liquid, and the other three parts must be filled with the very best sulphuric ether. If this be rightly managed, the two liquids will not mix. Then place the tube in a horizontal position, and gently turn it round with the finger and thumb. The ether will very soon bo impregnated with the gold or platina, which may be known by its changing its color; replace it in a perpendicular position, and let it rest for 24 hours, having first stopped up the upper orifice with a cork. The liquid will then be divided into two parts - the darkest coloring being underneath. To separate them, take out the cork and let the dark liquid flow out; when it has disappeared, stop the tube immediately with the cork, and what remains in the tube is fit for use, and may be called gilding liquid. Let it be put into a bottle, and tightly corked. The muriate of gold or platina, formed by digesting these metals in nitro-muriatic acid, must be entirely free from all excess of acid, because it will otherwise act too forcibly on the steel, and cause the coating of gold to peel off. Pure gold must be employed; the ether must not be shaken with the muriate of gold, as is advised by some, for it will then be sure to contain acid; but if the two liquids be brought continually into contact by the motion described, the affinity between ether and gold is so strong as to overcome the obstacle of gravity, and it will hold the gold in solution. The ethereal solution may also be concentrated by gentle evaporation.