Rolling Ingot 1:18 Keyring

My buddies over at Melville Metlaworks have a regularly repeating order for mellting old zinc into fresh skimmed zinc ingots. They've been doing htis for years in green-sand, which is incredibly labor intenseive. By creating this 3D-printable pattern for making identical BUT REUSABLE ingot molds out of cast-iron, I'll be able to eliminate their need for any sand & mold-making at all doing this particular job. Cast this pattern in iron, coat it with "ladle coat" powder, and with periodic re-coating upkeep, these ingots molds should be reusable almost indeffinitely.

Shapeways can't actually print this 30in thing full-size, so I'm only posting the keyring-size demo.