Raku Firing of Enamel With Silver PMC and Art Clay.

By Dorothy Cockrell and Joseph A. Ontko Ph.D.

Silver nitrate and raku firing have long been used to produce silvery patterns on enamel. There are certain difficulties in this process, ranging from the procurement of silver nitrate, the necessity of keeping the crystals and solutions away from light lest they deteriorate, through problems connected with controlling the various solutions, to the deep brown staining which can develop on hands, clothing, and work surfaces. Mixing an appropriate strength of any solution often requires making several test pieces.

It occurred to me that perhaps more modern materials could be used to produce the same effects with less trouble.

Therefore when packing my tutorial tool box for a raku firing workshop at the John C. Campbell Folk School, I included a very ancient unused piece of the original type of silver PMC (Precious Metal Clay). It was so old that it had hardened into a small bullet and re-quired breaking up and two days soaking in water to re-constitute it.
In a quiet moment I painted some of the resulting slip onto a pre- enamelled copper blank and fired it to burn off the organic binder. The result was a greyish patch of enamel.

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