Enameling on copper

Answer to Ken Roberts’ (new member
[Welcome] New Members for January 17, 2011 - Jewelry Discussion - Ganoksin Orchid Jewelry Forum Community for Jewelers and Metalsmiths) question.
In the late 60s I met an enamelist working with Sydney Nolan on a
large commission for a London bank.

He had a technique where he covered the surface of preformed copper
sheets with clear enamel powder. Then he worked on the reverse side
of the sheet with a large propane torch. By the amount of heat he
used and the time of exposure he got a variety of subtle colours
caused by the copper oxydation.

I cant remember all the details, he also had a small intense flame
for delineation.

I think he mixed gum tragacanthe or gum aribic with the clear enamel
powder and painted it on in a thin layer, on to very clean copper
sheet, letting it dry before heating from the back. Use a mirror to
see what you are doing.

I dont know if he counter-enameled the back and he could sieve on
more enamel powder if necessary and re heat. Have fun. Experiment,
experiment, experiment!

David Cruickshank (Australia)
jewellerydavidcruickshank.com.au

You can buy a clear enamel that contains a high concentration of
borax that fluxes copper brilliantly. It is commonly used as a
counterenamel or base coat for transparent enamels. I have seen some
lovely effects of its use on copper sheet that has been
etched/oxidised or the like. There is a slight downside, it is
soluble in acids so cleaning afterwards is not as straighforward as
using the older lead oxide enamels (common in the 1960’s but almost
unavailable now). The gum tragaganth is mixed with water and the
enamel and makes the powder stick when it is dry. The gum is used for
glazing icing on cakes and similar cooking type tasks but has a lot
to recommend it for when working o surfaces that are not flat when
enamelling. You can use guar gum and others instead, common ineurope
but I havent read any US enamelling books so dont know about
elsewhere.

Nick Royall