Step 3: Flask and Casting Bench
The flask itself is simpler than people make it out to be. Just make a box without a top or bottom and cut it in half. Then use some thin material to make an alighment peice on two sides of the flask. If you consistantly have problems with the sand falling out, attach a small strip of wood around the edges of the cope and drag where they meet.
Most home setups use greensand to cast in. This can be ordered or easily made without much expense by mixing sand and bentonite. An 11 to 1 mix of sand and benotnite, respectfully, (or approximately 8% bentonite) is suggested.