Important: Safety Warning
This page describes trade processes that use dangerously toxic materials such as cyanide solutions, mercury amalgams, or strong acids. These processes require training, equipment, and precautions far beyond what the text describes.
This information has been left in for historical purposes but should not be acted upon.
Gilding
The three methods of gilding are: mechanical, chemical, and encaustic. Picture-frames, etc., are first oiled and then coated with whiting and glue, after which the gold size is applied to such parts as do not require burnishing; those which do are simply sized with the clear animal size. The gold-leaf is then applied with a brush. Electro-gilding is generally practised for metals. Water-gilding is simply applying a gold amalgam paste to the metal, and afterwards applying heat, which volatilizes the mercury, leaving the gold. The amalgam is made by placing grain or leaf gold 1 in a clean iron ladle, add mercury 8, and apply a gentle heat until the gold is dissolved, stir well with a clean iron rod, and run it on a clean slab. This, when cold, is the amalgam, ready for use.
The cleaned metal to be gilded is first rubbed over with a solution of nitrate of mercury, and at once covered with a thin coat of the amalgam. Heat is then applied to volatize the mercury, and the gold adheres. Cheaper gilding may be made by increasing the quantity of mercury in the amalgam. Steel may be gilded by dipping the polished article into the ethereal solution of gold; on withdrawing, the ether evaporates, leaving the gold. A cloth dipped in the solution and wiped over the article answers the purpose. See STAINS FOR METALS; TINNING; ZINC COATING.