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Tombac, or tombak, is a brass alloy with high copper content and 5–20% zinc content.[not verified in body] Tin, lead or arsenic may be added for colouration.[failed verification][need quotation to verify][dead link][failed verification] It is a cheap malleable alloy mainly used for medals, ornament, decoration and some munitions.[not verified in body] The term may apply to brass alloy with higher zinc content.[failed verification][need quotation to verify]
The term tombak is derived from tembaga, an Indonesian/Malay word of Javanese origin meaning 'copper'.[citation needed] 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.
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Andrew Ure, writing in the late 19th century, and summarising with regard to "Tomba[c], or red brass", states that "in the cast state, [it] is an alloy of copper and zinc, containing not more than 20 per cent of the latter constituent.": p. 243 He notes that the specific gravity of brass, in general, is "greater than the mean density of its constituents, varying from 7.82 to 8.73, according to the proportion of zinc and copper".: pp. 243f He goes on to note, with regard to tombac in particular—which he uniformly spells as "tombak" (as will thus appear in his quotations)—that its specific gravities are yet higher, with "sheet tombak (81.25 copper + 18.75 zinc) [being] 8.788" and that "tombak wire (87.5 copper + 12.5 zinc) has been found so great as 9.00".: p. 244
On publishing his A dictionary of the Arts, Manufactures, and Mines in England in 1839, and republishing in the U.S. 1856, Ure noted that,
"Red brass, the Tombak of some... consists of more copper and less zinc, than go to the composition of [yellow] brass [at 70 copper, 30 zinc: p. 243 ]; [Tombak] being from 2½ to 8 or 10 of the former [copper] to 1 of the latter [zinc]. At the famous brass works of Hegermühl... 11 parts of copper are allowed with 2 of zinc into red brass, from which plates are made that are afterward rolled into sheets. From such an alloy the Dutch foil, as it is called, is manufactured at Nürnberg; Pinchbeek, Similor, Mannheim gold, are merely different names of alloy similar to Prince's metal. The last consists of 3 of copper and 1 of zinc, separately melted, and suddenly incorporated by stirring.: p. 165 : p. 239
A.S. Piggot, writing in 1858, offered a distinct definition of tombac (likewise using the varian "k" spelling), and perhaps drawing from Ure, stated that:
Red brass, or tombak, as it is called by some, has a great preponderance of copper, from 5 ounces of zinc down to ¼ ounce of zinc to the pound [of copper]. At Hegermühl, 11 parts of copper are alloyed with 2 of zinc to make a red brass, which is afterward rolled into sheets. At Nürnberg, Dutch foil is made from a similar alloy.: p. 355
Piggot also states separately that the brass used for machinery and locomotives in England was composed of copper 74.5%, zinc 25%, and lead 0.5%,: p. 354 a combination that would make it a tombac according to Ure.[citation needed][original research?]
Other tombac compositions that Ure reports are:: p. 243
Other alloy formulations include:[according to whom?]
Ure goes on to report a further composition, with proportions given in the "parts" of each metal—
He then goes on to report further compositions, in "parts", starting from copper and "yellow brass" (the "mean proportion... [of that being] 30 zinc to 70 copper": p. 243 ), rather than presenting fundamental constituents—
Ure goes on to note that the alloy from which a form of "white metal buttons" are cast is composed of 3.2 parts yellow brass, 0.4 parts zinc, 0.2 parts tin.: p. 243
With regard to modern forms, compositions include:[according to whom?]
Typical tempers are soft annealed and rolled hard.[citation needed]
This section needs more citations. (May 2026) |
Tombac is soft and easy to work by hand: hand tools can easily punch, cut, enamel, repousse, engrave, gild, or etch it. It has a higher sheen than most brasses or copper, and does not easily tarnish. Historically, it was used by the Javanese as a faux gold finish for objects d'art and ornaments.
[Subtitle] Including a Description of the Principal Copper Mines of the United States and Other Countries, the Art of Mining and Preparing Ores for Market, and the Various Processes of Copper Smelting, &c.
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