Pouring molten metal into three-dimensional molds to make metal parts is the basis behind both sand and investment casting. But there are significant differences between these two methods. In sand ...

You can melt down almost any kind of aluminum—cans, even—but a piece that has already been cast (such as a water pump, wheel, or intake manifold) will have an alloy that's better suited for casting.

Making silicone molds seems easy, but there are a lot of missteps to be made along the way that can mean the difference between a great, reusable mold, and one that’s a sad waste of silicone. If ...