3728. To Prepare a Solution of Gold

3728.    To Prepare a Solution of Gold. Dissolve 4 troy ounces cyanide of potassium and 1 ounce cyanide of gold in 1 gallon rain or distilled water. This solution is to be used at about 90o Fahr., with a battery of at least two cells. Gold can be deposited, of various shades to suit the taste, by adding to the gold solution a small quantity of the cyanides of silver, copper, or zinc, and a few drops of hydrosulphuret of ammonia.

3729. To Prepare a Gold Solution by the Battery Process

3729.    To Prepare a Gold Solution by the Battery Process. To prepare a gallon of gold solution, dissolve 4 ounces cyanide of potassium in 1 gallon water, and heat the solution to 150° Fahr.; now take a small porous cell and fill it with this cyanide solution, and place it inside the gallon of solution; into this cell is put a small plate of iron or copper, and attached by a wire to the zinc pole of a battery. A piece of gold is placed into the largo solution, facing the plate in the porous cell, and attached to the silver of the battery. The whole is allowed to remain in action until the gold, which is to be taken out from time to time and weighed, has lost the quantity required in solution. By this means a solution of any strength can bo made, according to the time allowed. The solution in the porous cell, unless the action has continued long, will have no gold, and may be thrown away. Half an hour will suffice for a small quantity of solution - of course any quantity of solution may be made up by the same means. For all the operations of gilding by the cyanide solution, it must be heated to at least 130° Fahr. The articles to be gilt are cleaned in the way described for silver (see No. 3705 (To Cleanse Articles for Electroplating)), but are not clipped into nitric acid previous to being put into the gold solution. 3 or four minutes is sufficient time to gild any small article. After the articles are cleaned and dried they are weighed, and, when gilt, they are weighed again; thus the quantity of gold deposited is ascertained. Any convenient means may be adopted for heating the solution. The one generally adopted is to put a stoneware pan containing the solution into an iron or tin-plate vessel filled with water, which is kept at the boiling point either by being placed upon a hot plate or over gas. The hotter the solution the less battery power is required. Generally a battery of 3 or 4 cells is used for gilding, and the solution is kept at 130° to 150° Fahr. But 1 cell will answer if the solu-is heated to 200°.

3730. Process of Electro-Gilding

3730. Process of Electro-Gilding. The process of gilding is generally performed upon silver articles. The method of proceeding is as follows: When the articles are cleaned as described in No. 3705, they are weighed, and well scratched with wire brushes, which cleanse away any tarnish from the surface, and prevents the formation of air-bubbles. They are then kept in clean water until it is convenient to immerse them in the gold solution. One immersion is then given, which merely imparts a blush of gold; they are taken out and again brushed; they are then put back into the solution and kept there for 3 or 4 minutes, which will be sufficient if the solution and battery are in good condition; but the length of time necessarily depends on these two conditions, which must be studied and regulated by the operator.