Thursday, August 19, 2010

Fast Fire BronzClay - My First Look

I have had a packet of Fast Fire BronzClay sitting on my bench beckoning to me for a week or so, but I haven't been able to sit down and try it.  Finally, I was able to make some time.

I have not used the regular BronzClay due to the long firing time required.  Turns out my kiln, which is a fiber kiln not a fire brick one, is probably not ideal for long firings like that anyway.   I have tried both of the copper clays:  ArtClayCopper and CopprClay and the jury is still out on them.  I haven't been able to get consistent results from them like I have with PMC.   PMC3 will always be my favorite, I think.

I had read that the new BronzClay feels like marshmallow.  I can't compare to the old, but I can say that I do see why people would say that.  It's got a lighter, less dense, feeling than silver or copper clay.  I kind of liked the feeling.  It didn't seem to dry out too quickly and took a texture quite well.  I only bought 30 grams, which didn't go very far because I made a fairly large and thick piece from a butterfly metal stamping.

Once dry, the BronzClay feels more flexible than silver and copper.  Silver, especially, is fairly rigid when fully dry, but the BronzClay was bendable and I was afraid I would break it.  It feels softer when filing it as well.  Wet clay seems to stick well to dry so it's easy to fill cracks and holes.

I fired it in carbon for two hours at 1525 degrees as per the directions.  I put it in the kiln before I went to bed and just waited until morning to take it out.  It was covered with a crust (oxidation) that wouldn't easily wash off in running water (although the instructions said that it would).  Pickling removed some, but polishing with my 3M polishing wheels removed it better (I started with the yellow wheel and moved up). 

I am not entirely happy with the finished product.  The bottom of the butterfly's left wing has lost some detail and also has some pitting, and it was hard to remove the crusty stuff from the pits.  I bent the wings a bit to put the butterfly in a bit of a curve and it separated from the part of the body that I had added to the wings.  It does seem to be sintered all the way through, though.

Here is a photo of the bronze piece (right) beside the metal stamping I used for the design to illustrate the shrinkage, which is significant.  Even though they look the same color in this photo, the bronze butterfly is a nice warm gold, but polishing did not get it as shiny as I expected.  I did not try tumbling it.

All in all, it might be worth trying again.  Like the copper clays, I think I will have to experiment a lot before I can rely on it to do what I expect every time, like silver clay does.

One final note:  I found when first working with copper clay that I must be sensitive to copper, as my hands itched and I sneezed a lot when working with the dust.  Unfortunately, the bronze clay gave me the same reaction, which only stands to reason since bronze is an alloy that includes copper.


  1. They look awesome Lisa, I can't wait to see what you do with them!

  2. Very interesting info! I still don't know how you wrap your brain around it all :)

  3. love reading about your experiments! Helps us all who want to play with it!

  4. Thank you for sharing! I have been thinking about getting some. I still have a package of regular BronzeClay left, though. The 8 hour firing time is what has deterred me from using it. This sounds a lot better.

  5. I think it turned out great! I like how you walked us through the project!


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