I’ve just spent a fine week in a printmaking course – working into aluminium plates variously protected from and exposed to copper sulphate and salt solutions. Although the results were definitely varied as I tried to figure out vital questions such as “how much is too much” and “how long is long enough”, it was a great way to spend some time, playing with images directly rather digitally.
As well its use as for print making, etching creates a decorate effect in its own right – one of the other students etched into his hand-forged knives with excellent results. Such surface effects are definitely something I’d like to explore. Much cheaper, less toxic and more accessible than traditional etching chemicals, copper chloride (as sold in garden centres as a fungicide) works for aluminum, zinc and mild steel. Experimentation proved it does no more than slightly tarnish silver, but the internet promises that a similarly low-toxic solution of ferric chloride and citric acid will work for copper, brass and bronze. And through the magic of chemistry, the ferric chloride that has been used to etch copper turns
into … copper chloride (+ hydrochloric acid). Another site suggests hydrogen peroxide and other domestic chemicals will etch copper, and using a permanent marker as the resist. Some careful well-goggled and safety gloved experimentation may be in order!
Electro etching is another entire art/science – again, the internet seems keen to convince me that a home-made set up is entirely feasible. A chat with my son-the-electrician may be in order here … perhaps, once he’s finished installing my kiln, he’d like to build me another
Etching by all accounts much easier/quicker with reactive metals – such as the aluminium plates we were using in the print making – than it is with the slow-to-tarnish less reactive metals such as silver and gold; which makes sense. It all relates to their place on the periodic table, apparently. Ohh, I do so wish I’d paid much more attention to chemistry in school.
Listing some reference sites here, so I know where to find them later:
- Non-toxic Print (impressively detailed and practical site) Edinburgh etch for copper and Brassand Bordeaux etch for aluminium, zinc and mild steel . And electro-etch.
- Edinburgh Etch for jewelers
- Home-build electro-etching
- Camberwell Materials Library Ratios/concentrations / acids for etching jeweller; silver, pewter, copper and other metals
- The Guild of Enamellers electro-etching, using simple equipment
- Wikipedia has a perfectly good overview of the history with a bunch of links that I’ve yet to follow
- Teacher’s “lesson plan” – a guide for etching copper or brass with a class
- Makers Gallery – Etching silver – which I’d also very much like to try – non-electro, using ferric nitrate.