When the sculpture in clay is finalized, a rubber mold is taken. Following the rubber mold, wax is poured in the mold and an exact replica of the original clay sculpture is formed. Then the wax sculpture is submerged in a ceramic liquid which creates a fire proof shell. Once the shell solidifies, it is put in an oven to bake the wax out of the shell mold. That's were the "lost wax process" name came from.