This past weekend I experimented some more, this time making pieces to be used in jewelry. I have learned a few things from these experiments, which I will share here. I used ArtClay Copper but fired it using the firing schedule of COPPR Clay, as I have found this to be the best option.
I made several pieces: One pin, one failure, and some charms. The clay was still moist when I opened the package, but it did have a black layer of crud on it. I had expected this, having read it would happen, and simply scraped it off and discarded it. I'm glad this doesn't happen with silver clay! It would kill me to have to throw away as much silver as I did copper.
First on the failure: I have a terracotta cookie stamp with a Celtic looking wreath on it. My idea was to have it as a pendant. It didn't work well and the piece broke into two pieces during firing. It was the last piece I made and I am not sure if it was moist enough when I began working on it. The clay had some cracks in it that I tried to fix with slip. I had read also that anything that can absorb moisture (like wooden stamps, etc.) shouldn't be used with copper clay. I believe that applies to terracotta as well.
- Slip is not the best choice for fixing large cracks. The repairs did not stand up to the firing process.
- Copper clay seems to dry out quicker than silver clay and it's very important to keep it moist.
More lessons learned:
- Plain old copper wire purchased in the hardware store fires well with copper clay.
- Working with dry unfired copper clay is very messy. Everything gets coated with an orangey powder.
- Copper doesn't take a patina quite the way silver does. The blues and greens aren't as vibrant and it takes much longer to reach those colors in copper than in silver.
- Applying gel liver of sulphur undiluted directly to the copper will turn it black instantly (it's slower with silver), which is great if you want dark crevices, but aren't patient.
- Polishing the high spots removes patina well and gives the pieces a wonderful new-penny shine.
I will be working with copper clay more and more, by the looks of it. I am going to experiment with ways to include both copper and silver clay in the same piece.