Fine Clay Mixed with Sand: Worked Loam for Casting Moulds

Clay mixed with sand is loam, the stuff of bricks and of the clay mould packed round a wax model for casting. Soak the clay, work in fine sand, pick out every stone, and keep working it: the more it is worked, the denser and more uniform it gets. The picture: our diagram, clay and sand worked together and the stones picked out.