BRASS′-COLOUR. Syn. Brass-pigment, B.-bronze. Prep. 1. Grind copper filings, or the precipitated powder of copper, with a little red ochre. Red-coloured.
2. Gold-coloured brass, or Dutch leaf, reduced to a very fine powder. Yellow or gold coloured.
Obs. Before application these powders are mixed up with pale varnish, no more being worked up at once than is wanted for immediate use. They are also applied by dusting them over any surface previously covered with varnish to make them adhere.
BRASS-PASTE. Prep. 1. Soft soap, 2 oz.; rotten-stone, 4 oz.; beaten to a paste.
2. Rotten-stone made into a paste with sweet oil.
3. Rotten-stone, 4 oz.; oxalic acid (in fine powder), 1 oz.; sweet oil, 11⁄2 oz.; turpentine, q. s. to make a paste.
Obs. The above are used to clean brass-work, when neither varnished nor lacquered. The first and last are best applied with a little water; the second with a little spirit of turpentine or sweet oil. Both require friction with soft leather. See Brass-work, Pastes, &c.
BRASS PLATING. By simple dipping. A colour resembling brass is given to small articles of iron or steel by a long stirring in a suspended tub containing the following solution:—Water, 1 quart; sulphate of copper, and protochloride of tin crystallised, about 1-5th of an oz. each. The shades are modified by varying the proportions of the two salts.
BRASS-STAIN. Prep. 1. Sheet-brass (cut into small pieces) is exposed to a strong heat for 2 or 3 days, then powdered, and again further exposed in a like manner for several days; the whole is then reduced to fine powder, and exposed, a third time, to heat, testing it occasionally, to see if it be sufficiently burnt. When a little of it, fused with glass, makes the latter swell and froth up, the process is complete. It imparts to glass a green tint, passing into turquoise.
2. Equal parts of plate-brass and sulphur are stratified together in a crucible, and calcined, until they become friable; the whole is then reduced to powder, and exposed to heat as before. This imparts a calcedony red or yellow tinge to glass by fusion; the precise shade of colour being modified by the mode of using it.