A silicon rubber mould is used to make a wax copy of the original artwork. Unlike the original, the copy is hollow, like a chocolate egg. To create it, wax is poured into the mould, and this is swirled around to coat the interior. When this is released, the seamlines are cleaned up and gating is added to create a reservoir for the bronze. Pipes are added to allow the bronze to flow in and air to flow out. The rubber mould represents the the first negative copy of the original. This wax, which will later be lost, is the first positive copy. A sacrificial ceramic mould is built up around this copy. Learn more about the next step here.