3592. To Apply Gold Plating Powder

3592.    To Apply Gold Plating Powder. Make some gold plating powder into a paste with water, and rub it on the surface of the article with a piece of chamois skin or cotton flannel. The surface of the article should be thoroughly cleansed before applying the plating powder.

3593. Gilding Paste

3593.      Gilding Paste. Metallic surfaces are gilt by rubbing on the following mixture : Terchloride of gold, 36 parts ; dissolve in pure water, 36 parts, and mix with a solution of cyanide of potassium, 60 parts, in pure water, 80 parts; shake well, and set by for 15 minutes, then filter. This liquid is thickened with a powder composed of prepared chalk, 100 parts; cream of tartar, 5 parts.

3594. Fire Gilding

3594.    Fire Gilding. This was extensively done before the discovery of the art of electroplating. Many a piece of beautiful workmanship has come down to us from ancient Rome and Greece, gilded, and probably in the same way as we do it now, under the name of fire-gilding. It requires more gold, the coating being thicker, and is therefore more expensive; but it will last longer, and is the more convenient way for gilding coins and small articles. Clean the silver piece, by means of a brush and a little ammonia water, until the surface is evenly bright and shows no tarnish. Take a small piece of gold and dissolve it in about 4 times its volume of metallic mercury, which will in a short time be accomplished and an amalgam formed. (See Nos. 3533 (Amalgam of Gold for Gilding Brass, Copper, etc.) and 3534.) Put a little of this amalgam on a piece of dry cloth, and rub the silver piece with it on all sides; then place it on a clean stone in a furnace, and heat to the beginning of redness. After cooling it must be cleaned again with a brush and a little cream of tartar, when it will be found beautifully and lastingly gilded.

3595. To Remove the Gilding from Old China

3595.    To Remove the Gilding from Old China. The following method is recommended for removing the remains of gilding from old china: Take soft water, 8 parts by measure; nitric acid, 8 parts; common salt, 4 parts; sal-ammoniac, 1 part. Let it boil, put the china into it, and rub with a stiff brush.

3596. Wernicke's Method of Gilding Glass

3596.    Wernicke's Method of Gilding Glass. The following are the ingredients required : 1st. Solution of gold. Pure gold, free from silver, is dissolved in aqua regia, the solution evaporated, and the residue taken up with water, so that 120 cubic centimeters (1 gill) contain 1 gramme (15.4 grains) of gold. 2d. Solution of sodic hydrate (which need not be absolutely pure) of 1.06 specific gravity. 3d. Reducing liquid. CO grammes (7711/2 grains) sulphuric acid (monohydrate), 40 grammes (617 grains) alcohol, 35 grammes (539 grains) water, and 50 grammes powdered manganic peroxide, are distilled into 50 grammes of water until the bulk of the latter is doubled - 10 grammes (154 grains) cane-sugar, inverted by dissolving in 70 cubic centimeters (6/10 gill) water, and boling with 1/2 gramme, (71/2 grains) nitric acid of specific gravity 1.34. The distilled liquid, the inverted sugar, and 100 cubic centimeters (84/100 gill) alcohol are mixed together, and the mixture diluted to 500 cubic centimeters (11/10 pints). In using these solutions, 1 volume of the sodic hydrate solution is mixed with 4 volumes of the gold solution, and to this mixture is added from 1.35 to 1.30 volume of the reducing liquid. The object to be gilded is placed on the top of the solution, having the surface intended to be coated turned downwards. The temperature of the bath should be below 140° Fahr.