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Parent Category: Technical Articles from Journal Back Copies

Category: Technical Articles 2002

Occasionally members of the Guild are asked for advice on repairing old damaged pieces with enamel. Wisely, most of us fight shy of such requests - making generalised excuses on the lines of it being a tricky operation. Recently the editor came across the following reasoned article, written by an experienced senior professional and felt it would be of interest and use to members.

"Enamels can change colour during re-firing and if antique jewellery is heated, this will also weaken and can destroy any solder joints. Because the recipes for enamels are always changing, it would be impossible to produce exactly the same "mixture", though it would be possible to make a colour match. If new enamel was added and fired with the old, this could cause further damage to the old enamel and, even if a perfect result ensued, the process would be irreversible and hence unethical. When applied to a museum piece it might also be impossible, if successful, to say what was original and what was new. Heating could also destroy or confuse scientific evidence if tests were made later. Enamel can change colour with each firing, particularly with reds and yellows. It is impossible to know the original firing temperature that produced those particular shades and a perfect match on a test piece of modern metal could result in two different shades when fired with the original.

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