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.
Tobin-bronze
See DELTA-METAL.
Tombac is a cheap gilding metal for common jewelry, and purposes where it is desired to substitute for the nobler metals a cheap imitation. Those given in the following table are made by first fusing the copper and adding the remainder afterward in the usual way-except in the case of white tombac: in this alloy the two metals copper and arsenic are melted together in a closed crucible, and well covered with common salt to prevent oxidation. Kinds of Tombac. Copper. Zinc. Tin. Arsenic. Brass. Lead. Gold, imitation..... 16 1 1 Silver-white, for buttons, etc. ..... 75 25 Red..... 11 1 Gilding for common jewelry..... 16 1 to 1 1/4 Gilding for common jewelry..... 16 6 Gilding for common jewelry..... 16 3 to 4 Gilding for common jewelry..... 82 18 1 3 French imitation gold..... 80 17 3 Yellow, gilt ornaments..... 85.3 14.7