Step 1: Wax Shape
Step 2: Mould
I covered the wax shape with a thin layer of compound to ensure it was completely covered and any air bubbles wouldn't affect the overall shape. After it was left to dry over night, the whole thing was placed into a lager cup of drywall compound with the sprue sticking up and left for a few days to dry.
Step 3: Lost Wax
I used a soup can as a crucible and melted the coin with a mapp gas torch. Mapp gas burns in air at roughly 3700 F.