Turritella Designs

The last few weeks I’ve tried out three types of new metal clay – one silver, one copper, and one bronze.

FYI (For Your Inspiration) fine silver metal clay

The clay comes out of the package feeling quite dry. Instead of instantly trying to re-hydrate it, I rolled the clay into a ball and kneaded it with my fingers. Luckily this seemed to be just the right thing to do - the clay seemed to relax from its original dry lump and became quite workable without the addition of water. The clay is very similar in consistency to PMC Flex, and has a long and comfortable working time. The shrinkage seems to be a bit variable, but my pieces didn’t distort. I think this clay will end up displacing PMC Flex as my favouite type to work with, once I get used to the increased shrinkage.

Prometheus Copper Clay

This clay is easy to work with, but is a bit grainy in texture. The copper clay took texture well, but took longer than I expected to dry thoroughly. The clay is quite hard in the green-ware stage, but was easy to refine using files and sandpaper.

Unfortunately my kiln pyrometer is a bit off, and my first firing of this clay was unsuccessful. My second firing went well, though. I used the 30 minute fire-and-quench method, and then pickled and tumbled the metal. I was left with a nice shiny piece of copper that I think should take enamel well.

Prometheus Bronze Clay

This clay behaved similarly to the copper in the green-ware stage.

On my first try, my kiln fired low and my pieces didn’t sinter. Three tries later at increasing temperatures and I finally got sintered metal, however the colour of the clay is much closer to copper than it is to yellow bronze.

One again I used the 30 minute fire-and-quench method when I was trying to sinter this bronze clay. I think perhaps I would have better luck if I tried the carbon method. I have heard that the colour of the clay is much more yellow when it is fired in carbon, however I haven’t yet had a chance to see for myself.

Enamelling on Prometheus clays

Both the sintered copper and bronze clay took opaque enamel well. Because copper and bronze are reactive and produce black oxides when they are heated, I tried to complete my designs in as few firings as possible. I got a fine black line of oxides around the edges of my enamel designs, however I quite like the look as a design element because it seems to emphasize the colours of the enamel.

Final thoughts on Prometheus clays

I like the idea of being able to work a little larger with the more economical clay. I’ll definitely be making more enamelled copper pieces in the future. I’ll need to experiment more with the bronze firing schedules to see if the metal colour is actually more yellow when fired in carbon before I try to enamel any more bronze pieces. At the moment I don’t think the fuss with firing is worth it when the colour of the sintered metal is almost indistinguishable from copper.