Build a foundry and sand-cast aluminum.

Step 3 Read up. Arm yourself with knowledge

Casting metals can be complicated. It's a good idea to get a feel for it first.

Metal-casting Instructables.
http://www.instructables.com/id/Waste-Oil-Furnace-For-Melting-Metal/
http://www.instructables.com/id/Building-a-furnace-creating-molds-and-casting-je/
http://www.instructables.com/id/Quick_cheap_and_dirty_aluminum_melting_furnace_s/
http://www.instructables.com/id/Coffe-Can-Aluminum-Foundry/
http://www.instructables.com/id/Waste-Oil-Forge-and-Foundry/
http://www.instructables.com/id/Pizza-Sauce-Can-Furnace/
http://www.instructables.com/id/Aluminum_Foundry/

Some good examples of what we're doing.
http://www.visi.com/~darus/foundry/
http://www.gizmology.net/furnace.htm

A list of even MORE links.
http://www.abymc.com/Links.html