VermiculiteYou can buy vermiculite at most garden stores, but it's also on the web if you happen to live far from garden stores. In essence vermiculite, for PMC purposes, is a "non burning support system." That is, it's sort of like sand in the way it works. You can put it into a bowl or make a small pile of it. It will support your PMC shape with the wings out or the center fluffed out, and not burn away when the kiln heats up.
So if you're making flat shapes you don't need vermiculite. If you're making three dimensional shapes with "arms" or legs or wings that stick out, normally those would flop down when the clay is still soft. The vermiculite lets you support those appendages until the clay solidifies into metal and gets solid and stiff. So for example when I make origami cranes, the wings stick out to the side. If they were unsupported they would flop down and touch the ground. I rest the crane in a pile of vermiculite, and the vermiculite holds the wings up. Then when the kiln process is done and the crane is now metal, the wings are in the proper position.
You can reuse vermiculite a number of times before you have to get new stuff. It's fairly cheap so this isn't a big deal.
Note you want to get a bowl to hold the vermiculite, so the little grains don't get all over your kiln. You need a kiln-safe bowl of course!
Vermiculite from Amazon.com
PMC - Precious Metal Clay
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