The SIAL grog is made by RHI Refractories. Christy is from Christy Minerals. The Mullite is not really a grog but neither is it a powder, it is made by Mulcoa Refractories.
Grog is a term used in ceramics to describe crushed brick (or other fired ceramic) aggregate that is added to sculpture and structural clays to improve drying properties.
Sign up at the home page.