Enamelling on Copper

Copper is preferred to Gilding Metal, and if Gilding Metal is used it must be 90/10 quality. 20’s gauge (0.9mm) is a suitable thickness. The metal should be degreased by heating to about 800°C, a bright red heat. The scale formed can be removed by dropping into cold water immediately. The metal is then reasonably clean and suitable for enamelling, after wiping with a clean dry cloth or paper tissue. If a transparent enamel is to be used, any discolouration of the metal will show on the finished piece as a darker colour. To avoid this clean the copper either with the special metal cleaner listed or abrasive sponge listed and wash with water. After washing avoid fingering the surface.

For high class work the metal may be pickled to a clean, bright colour by immersing in 10% Sulphuric Acid for 10 to 15 minutes and washing thoroughly in hot water, but this is not necessary for routine enamelling. Similarly, if absolute transparency is required, it is advisable to wash the transparent enamels by stirring in water, and pouring off the very fine particles which remain in suspension. The enamels should then be dried thoroughly. Otherwise, washing is not necessary.

The enamel should be stored in air tight jars in a dry place. Dust the enamel powder through a sieve on to the copper. If the enamel is too thin small round blackish marks may appear on firing. If it is too thick the enamel will crawl and may be liable to crack or chip. At first it is better for the enamel to be too thin, then a second coat can be applied and fired.

Dry and fuse the enamel either in a kiln for 2-3 minutes at 800-820°C or by applying a suitable gas/air or propane torch to the back of the metal until the enamel is fused and glossy.