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.
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To Color Brass Grey-Green
Dipped into a bath of copper, the brass being first polished, as in last receipt, the resulting tint is a grayish green. 3335. Το Color Brass Violet. A beautiful violet is obtained by immersing the polished brass for a single instant in a solution of chloride of antimony, and rubbing it with a stick covered with cotton. The temperature of the brass at the time the operation is in progress has a great influence upon the beauty and delicacy of the tint; in this instance it should be heated to a degree so as just to be tolerable to the touch. 3386. To Give Brass a Moiré Appearance. A moiré appearance, vastly superior to that usually seen, is produced by boiling the object in a solution of sulphate of tarnish, rendering the metal bright. The acid must be washed off with water, and the brass rubbed with whitening in powder and soft leather. When acids are employed for removing the oxide from brass, the metal must be thoroughly washed afterwards, or it will tarnish in a few minutes after being exposed to the air. 3390. Το Give a Golden Color to Brass. A mixture of muriatic acid and alum dissolved in water imparts a golden color to brass articles that are steeped in it for a few seconds.