By Raymond Jackson
Some Observations on Applying Transparent Enamels to Copper
Silver and gold are attractive metals for enamelling because of their intrinsic value and because they possess high reflecting properties, allowing transparent enamels to be shown to best advantage. In addition, gold and silver alloys do not oxidize significantly at the temperatures needed to fuse the enamels to them. Although minor oxidation can cause some transparent enamels to discolour, there are well established techniques to enable enamel clarity and colour to be of a very high order.
In contrast, copper presents a problem for transparent enamels, namely the rapid and significant oxidation that takes place when copper is heated to enamelling temperatures, (in the range 7000C – 10000C). Inexperienced enamellers might conclude it virtually impossible to achieve results quite as good as those on gold or silver. This may be true, but there is much published information on how to mitigate the discoloration of transparent enamels caused by the copper oxide that develops on the surface of the metal.
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