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.
Brown Bronze
Brown bronze is prepared the same as blue bronze but the blue bronze is finally rubbed over with a linen rag saturated with olive oil, which will change the blue color into brown.
Brown Stain for Copper. To produce a dark-brown color upon copper, take the white of an egg, beat it into froth, add a little boiled or rain water, and add to this mixture caput mortuum (red oxide of iron); rub them well together in a mortar, and sufficiently thick until the color covers, and may be applied. The copper articles are to be pickled and simply washed; no sand must be used, else the color adheres badly. The latter is next applied with a brush until it covers the surface it is then dried by a fire, the article is gently rubbed with a soft rag and caput mortuum powder, and finally hammered with a hammer with polished face.
Brown Stain for Gun Barrels. Mix 12 parts of a solution of sulphate of iron, 16 parts of sulphate of copper, 16 parts of sweet spirit of nitre and 12 parts of butter of antimony. Let the mixture stand in a well corked bottle for twenty-four hours and then add 500 parts of rain water. Thoroughly polish and clean the barrels, wash with fresh lime water, dry thoroughly and apply the mixture evenly with a piece of cotton. After drying for twenty-four hours, brush with a scratch brush and repeat the coating. Do this twice, the last time using leather moistened with olive oil in lieu of the scratch brush, rubbing thoroughly. After standing for ten or twelve hours, repeat the polishing with sweet oil and leather until a beautiful polish is obtained.