I've hacked the Aluminum casting process right down to nothing. No longer is metal casting the domain of big hairy dudes in sleeveless Iron Maiden Tees. This instructable will show you how to cast aluminum parts in 5 minutes with little more than a stick welder, some graphite and kid's toy Kinetic Sand.
Step 1: Kinetic Sand, Behold SCIENCE!
Kinetic sand is a weird material, it flows like a fluid, yet it is mainly sand. The unpronounceable magic ingredient is inert, in fact, it's used in fast food to minimize frothing in the deep fryer. ( ick!)
But the really great thing about it, is it doesn't melt or burn. At high temperature it vitrifies, like glass or clay.
So kinetic sand makes a great replacement for traditional metal casting green sand molds. Don't have green sand for casting molten metal? Me neither.
Step 2: Use a Graphite Crucible and Gouging Electrode
Plain old hum-drum graphite (pencil lead) is also an amazing material. It is electrically conductive, and can withstand temperatures that will melt metal. Put your scrap aluminum in the crucible (I got mine on flea bay) and use a carbon air arc gouging electrode (from welding supplier; ask nice and they may give you a few samples! Or PM me and I'll send you a couple broken in two in a letter envelope ;-).
Step 3: Fire Up Your Stick Welder and Melt the Aluminum
In the vid, I start out with 50 amps output from a DC arc welder. I set the polarity to electrode positive and strike an arc on the aluminum in the crucible. After a brief period, I decided to increase the amperage to 110. That amount of current melted the aluminum within a minute.
Then pour it into your kinetic sand mold.
Aluminum Casting: Done.
You can improve the quality by adding a little ground up chalk to the bottom of the crucible, and by skimming off the dross floating on top of the molten aluminum prior to pouring.
Be sure to check out the vid at the beginning of this instructable for much more detail. It's about 8 minutes long and well worth the price of admission!