A team effort, we ordered dangerous chemicals and donned aprons.
While I broke the artwork into parts so that it could be laser copied (back to front) onto the special blue paper used to make a black ‘resist' on the copper, Graham cleaned the surface of the little copper tests sheets supplied by Art Fabrications.
We then heated the copper sheets one by one on the hotplate of the woodburner and brought it over to the ironing board, put the artwork on its blue paper over the copper, and ironed gently, peeling back to check that the line work was fully transferred. We played with different temperatures and ironing times so that we had a range of test sheets to monitor.
After this, the test sheets were put into a chemical bath of ferric chloride and immersed for four different time periods in a tub outside - again, to check which length of time worked best. We didn’t want the etch to be so deep it created too much shadow or distortion, and neither did we want it to be a mere tickling of the copper’s surface.
Once we were satisfied we had a version we liked, we took the timings from the most successful test and started cleaning up the album-sized copper (well I say ‘we’ - Graham took this one for the team, with wire wool and sore knees) - check this ‘before’n’after':
Artwork was once again flipped and carefully positioned in two parts:
…and ironed on (the Glove Of Doom is because the copper is very hot at this point):
Then the paper’s peeled off to reveal…
After which point, the copper was lowered in its Heath Robinson-esque cradle of string and magnets into a much larger tub of ferric chloride, while the magic happened. This is how it came out:
And the last-but-two process - removing the resist with common nail varnish remover, to reveal glittering copper beneath! (Tip: don’t be tempted to use acetone free nail varnish remover to save your fingers - bike down Asda and get the real cheap nasty shit and put gloves on - it comes off in SECONDS!)
A final polish of the finished etching with lemon juice and salt:
And here is the finished piece:
Interestingly, despite a sealing with a special and expensive protective wax, we think there was another finishing stage to go through, as the piece continued to age and oxidise quite deliciously over the next few days - see how it changes: