It's a far cry from the traditional steel mill that remains in operation today — as a monument to a long-ago industrial revolution. Currently, ore is melted at blisteringly high temperatures into a soup, refined into desirable composition, and poured into ingots or slabs, which later can be shaped into parts and structures.

Modumetal's process involves none of that. The company's method of "growing" metal atom by atom applies electric current to the same kinds of raw materials, but without all the heat and fury. And in a much smaller space.

"You're not melting metal inside of a metal vat. We produce metal in a plastic swimming pool," said company CEO and cofounder Christina Lomasney. "There's no heat — it's just current. We can change the electric field to create layers. Everything operates at near room temperature, which reduces the capital expense of manufacturing. And it means we are fully compatible with the operating temperature of plastic, so we can produce hybrid plastic-metal composites."