Please explore the following internal links:

Casting Sand Recipes

Refractory Recipe 

Lead and Zinc Metal Casting 

Metal Casting Pattern Howto

Future Metal Casting Patterns

Metal Casting Furnace 

External links (not on this site) that I find fascinating about the subject of Metal Casting / Metal Work.   Drop me an email if you want your site linked here!

http://www.emainc.com/radnor/  <-- This is where I got my idea for the bellows.

http://backyardmetalcasting.com/