I have taught myself how to make (fairly crude) aluminum castings.  My
texts were books on casting published by Lindsay Publications:

    http://www.lindsaybks.com/prod/index.html

My furnace is an electric kiln about 8x8x4 inches inside.  I bought it
for fusing glass, and it cost a few hundred dollars.  My crucible is a
cast-iron pot.  The results of my casting efforts were used for boat
parts.  But I will be casting my own organ parts when appropriate.

Wallace Venable