By Raymond Jackson - UK

Introduction

In the Guild of Enamellers Journal, (Spring 2000), Dorothy Cockrell described how to build an electric etching kit and to prepare small pieces of copper or silver for etching using a weak solution of acid. It is a relatively safe and clean method of producing items for Champlevé enamelling.

At that time, I was relief etching copper using the more conventional Ferric Chloride solution. Relief etching is the eating away of large areas of metal as opposed to line etching which results from scribing through a pre-applied resist. Ferric Chloride is not a very agreeable chemical and the etching process creates bubbles and deposits and the solution must be carefully disposed of when exhausted. A development that alleviates the unpleasantness of Ferric Chloride is Edinburgh Etch. This involves adding citric acid to the solution and this speeds up the process, dissolves the sediment, creates less bubbles and the solution has a longer life.

Despite this improvement to the mordant, I was keen to try electro-etching as it uses less aggressive chemicals and it should give a more controllable etch. Starting with Dorothy's work, I have gradually progressed with this technique. In doing so, I have relied heavily on the work of Cedric Green, (see References), who has explained and identified the benefits of using copper sulphate solution as the electrolyte and the use of new resists. He places considerable emphasis on the benefits of using non-toxic chemicals for etching copper and other metals. Although his work is aimed primarily at the printmaker, much is of direct application to Champlevé enamelling.

So I have set down theses notes of my own experiences with electro-etching copper. My work is not definitive and there are many other techniques for electro-etching copper. Others embarking down this road may, nevertheless, find the information helpful.

Download the full article here: Relief Electrohttp://www.guildofenamellers.org

First published in Guild of Enamellers Journal 2008-2009

I thought this was a thorough article with very precise documentation of the writer's experience.  Those who have used ferric chloride as an etchant may take exception to the introduction's erroneous reference to bubbles being created during etching with it (unless you are adding bubbles via an aquarium pump). Ferric chloride does not produce gas bubbles, but reacts with copper to create salts. At first I thought he may have been thinking of nitric acid which does produce harmful gas bubbles when reacting with metal, and is, as he says, "not a very agreeable chemical."  But then I was further confused because nitric acid is used in this particular study…hardly a less-aggressive chemical than ferric chloride!  Enough on that….fortunately, there are alternative electrolytic solutions mentioned in the article. The Lascaux resist products referred to are available from www.graphicchemical.com if someone is looking for a supplier. I have found that Armstrong no wax floor stripper will remove the resist if you run out of their remover.  The photopolymer resists, such as Image-on, hold on in an electrolytic etch too. What is nice about this method of etching is that, unlike acid etching which tends to undercut the side walls when etched deeply, electrolytic etching cuts the design straight down.  I've really enjoyed reading the different enamelists' methods in this forum.