The first stage of the Lost Wax Sosi process involves creating a wax model of the part to be manufactured. This wax model is then coated with a refractory material, such as sand, ceramic or brick, to form a shell.

The shell is then heated to melt the wax, leaving a hollow refractory mould inside the shell. This mould is then filled with molten metal to form the final part. After cooling, the shell is broken to reveal the final casting.