There's a foundry down the road from me, but the foundry manager I talked to seemed to not know what "fire clay" was. He pointed me to his supplier's website (mainly to get me off the phone, I think) but there's no refractory information of any kind there, all they have is equipment I don't need. Some here mentioned "perlite". I've googled for "perlite" and everyone that's used it also used fire clay, so that's no help. Even Budget Casting Supply
Can anyone who has actually used fire clay provide a brand name from the bag? Searching for a specific item rather than the protean "fire clay" (everybody seems to call this stuff by a different generic name and/or have different things in mind for any given name) would be a lot easier. No need to tell me to check my "local fireplace/potter/construction/masonry supplier"--that's been done to death.