The moon is rotten with metal oxides. Powdered metal oxides. If you can work out how to do smelting and metallurgy in low G, then the moon as a manufacturing base for a stellar civilization has its attractions. We can't manage a Mars Colony (like capital C colony, not camping trip) from Earth. But from the moon? The physics is certainly better, but I'm not so sure about the logistics.

Does anyone know if convection is a net positive or negative when smelting metal? I know that one way to remove impurities is to cast a billet and then saw off the bottom and top edge, where the heavy and the light contaminants tend to come out of suspension. But is that a boon or just making the most of a bad situation?