I have managed successfully to cast some pewter into an interesting medallion (which I will probably melt down) what I did is: first I packed down some wet sand and carved out my design, then put the pewter into a pie-pan and put that into the oven (500 degrees F) I (well, Dad) poured the molten pewter into the sand cast, let that harden then put it in cold water to cool it. I made two crosses in a similar way by placing pieces of pewter in the cast and used a blowtorch to melt them together.