Saturday, 12 February 2011

Blistering Fastfire Bronze Clay

This was my first experience with Bronze clay of any kind.
I chose the FastFire version (from metal clay adventures),because its firing properties seemed similar to the artclay silver I'm used to

I also used the Cool Tools brand of no flake foil, to avoid the spalling and sooty mess, you get with a steel pan. You create a box, by folding it, origami style, and cut some slits on the top lid for ventilation

What I didn't factor in, was that in my experience, the flake foil box allows the kiln temperature to permeate the piece, better than the steel pan, so it sent the prescribed firing temperatures out of whack.

Most first time FastFire Bronze clay users according to their blogs, found they had to increase the ramp, or holding kiln temperature to ensure the test piece is fully sintered

My problem was the reverse.I fired the test piece at 1525 F/830 C, holding for 2 hours, as recommended. This resulted in a very blistered, deformed thing emerging from the kiln, as you can see

I lowered the holding temp to 816 C, and the blistering was still present, but to a lesser extent

Finally at 800 C, the same temp as I fire my silver clay, the piece came out fine.This temp is significantly lower than most of the anecdotal reports I've seen on blogs

So I thought I'd document the blistering time I had, in case it comes in handy for someone else.(Btw, the kiln is a Paragon SC2 and the piece was fully sintered, no breaking or cracks even at that low temperature)

I'm now looking forward to finally getting to play with bronze, yay!!


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