Well... Like I said a very limited budget... I have tire rims laying in a pile but no brake drums haha. This is one where I can only use the material already on hand. I have a big pile of bricks, lava rocks, cinder blocks and tire rims.
As for the air, yes I was thinking attaching a larger pipe, most likely 2' and having the regulator set around 3-5 psi with a lever valve so I can open partially and increase the amount of control I have over the air.