Stoneware powder is one of our favorites in the lab as it has acceptable damp strength, good green strength, and mostly behaves in the kiln cycle.
SPS Stoneware Buff 1000 units
Powdered Sugar 250 units
Maltodextrin 250 units
If you can’t find Maltodextrin, then use Benefiber (it is no longer maltodextrin but rather a wheat dextrin).
M. Eden Torus: Stoneware Glazed and Unglazed.