Tombac, as it is spelled in French, or tombak, is a brassalloy with high copper content and 5–20% zinc content. Tin, lead or arsenic may be added for colouration. It is a :wikt:cheap|cheap malleable alloy mainly used for medals, ornament, decoration and some munitions. In older use, the term may apply to brass alloy with a zinc content as high as 28–35%.
Etymology
The term tombak is derived from tembaga, an Indonesian/Malay word of Javanese origin meaning copper. Tembaga entered Dutch usage concurrent with their colonisation of Indonesia. Likely, the term was used generically to describe Indonesian high-copper brass items, including gamelan gongs. It is one of the very few Indonesian loan words used in English or German.
modern CuZn12 - same characteristics and applications as CuZn15, slightly different colour
modern CuZn10 - similar characteristics and applications as CuZn15 und CuZn12, noticeable reddish colour
modern white tombac - CuZn10 that is zinc content 10%, with trace arsenic
modern enamel tombac or emailler tombak - an alloy of 95% copper and 5% zinc, suitable for enamelling, therefore the name.
Ure notes the following forms of tombak in widespread use during the time the text was published :
"Gilting tombac":
*Copper 82%, zinc 18%, lead 1.5%, tin 3%
*Copper 82%, zinc 18%, lead 3%, tin 1%
*Copper 82%, zinc 18%, lead, tin 0.2%
"French tombac for sword handles", pommels and fittings: copper 80%, zinc 17%, 3% tin
"Yellow tombac of Paris" for gilt ornaments: copper 85%, zinc 15%, trace% tin
"Hanover tombac": copper 85.3%, zinc 14.7%
Chrysochalk: copper 86%, zinc 14%
"Red tombac of Paris": copper 90%, zinc 7.9%, 1.5% lead
"Red tombac of Vienna": copper 97.8%, zinc 2.2%
Piggot states the brass used for machinery and locomotives in England was composed of copper 74.5%, zinc 25%, and lead 0.5%- which would make it a tombac according to Ure. Piggot's own definition of tombak is problematic at best: "red brass or tombak as it is called by some, has a great preponderance of copper, from 5 ounces of zinc down to 1/2 ounce of zinc to the pound "
Tempers
Typical tempers are soft annealed and rolled hard.
Applications
Tombac is easy and soft to work by hand: hand tools can easily punch, cut, enamel, repousse, engrave, gild, or :wikt:etch|etch it. It has a higher than most brasses or copper, and does not easily tarnish. Historically, it was used by the Javanese as a fauxgold finish for objects d'art and ornaments.
Most commonly, tombac in modern society is used in medals and awards of lesser importance, such as the German Oldenburg Long-Service Medallion for their Gendarmerie.
