I just want to pass along a tip. Yesterday, I made some objects from bronze clay. I fired them in a stainless steel container and let the kiln cool down overnight. Everything worked well except for the black flakes all over the kiln from the container. Such a mess. I remember that Hadar Jacobson had posted directions to make a firing box with fiber board a few days ago. I modified her directions and made a firing box to use the next time I fire copper or bronze clay.
After testing this box, I found that it works best without the cover. The brick is an insulator and doesn’t allow heat in with the cover on. Place your bronze or copper pieces into the charcoal and fire following manufacturers directions. No more mess in the kiln.
In addition, you can use the fiber board, as Hadar did, instead of brick to make the box , and be able to use the cover.
I cut fire brick pieces to make the box top, bottom and side walls. I used some Pyrolite EZ Fill ( from Paragon ) that is usually used to fix divots in the fiberglass kiln sides in the seams of the box.
The pyrolite isn’t sticky like a glue, but I used it because I wanted to prevent charcoal leakage along the seams. ( The box isn’t measured with precision. ) When it dries it will fill gaps. Binding wire is really holding the box together. The box measures 4.5”wide x 4.5” deep x 5” high.
I hope this will help all the base metal clay people out there.