As far as making liquid metal, [Ben] used a cast iron pot with a convenient pour spout, and a blowtorch. He added graphite powder to the molds in an effort to make them give up the goods more easily.

The search led to Graphicast, a New Hampshire casting and CNC facility that uses graphite molds to cast parts from ZA-12, a zinc-aluminum alloy that is harder, stronger, and more durable than ...