I went down to Turbine Flats yesterday to see how aluminum is melted down and then casted into other objects.
My friend Madeline works at Turbine, and she introduced me to Gene Wegner, who has been doing all kinds of stuff related to building and making for many years—from well sealing, to farming eight hundred acres of land.
First, everything is carefully cleaned to remove any dirt. Paint is left on (it burns off), but dirt turns into impurities in the melted aluminum, (slag) which must later be discarded
A guy running a bodyshop across the way kept pulling cars in and out
Gene used very fine sand mixed with bentonite clay to make a funnel for the liquid aluminum.
The crucible is made of graphite and silicon, heated by a propane tank. The propane runs into the chamber and air is injected in by a small electric fan, like an automatic bellows. It's a delicate process to keep the crucible from melting as well.
His son Matthew helped with the casting.
In the end, the cast object gets knocked out of the sand (at left). I didn't take any pictures of it, so you'll have to show up this Friday at Turbine Flats to see Gene give a presentation on smelting and casting.
Thanks to Gene and Madeline!