How to Make a Metal Casting Furnace

Cut a hole, 1 inch in diameter, in one of the buckets, about 3 inches from the bottom. Cut a similar hole about inch from the bottom of one of the coffee cans.

Roll several layers of cardboard around the coffee cans and staple them so they keep their shape. The cardboard should be large enough so that with the coffee cans inside the buckets that the cardboard will be taller than the rim of the bucket. Cut out a hole in the cardboard where you cut a hole in the can.

Mount the cans inside the buckets using long metal screws. The screws should be near the top rim of the bucket and should not pierce the cans. When in place, the screws should hold a can suspended in the center of each bucket, with a gap of 2 inches from the bottom of the can to the bottom of the bucket. Line up the hole in the bucket with the hole in the can suspended inside it.

Cover a 1-inch pipe with several layers of cardboard. Insert it through the holes in the bucket and in the can. Use the duct tape to seal around the holes and the pipe.

Fill the space between the bucket and the cans with refractory cement. Allow the cement to harden.

Remove the pipe, both cans, the cardboard and tape and discard. The buckets lined with cement are now the top and bottom halves of your furnace. The hole in the bottom half is where the burner will fit into the furnace while in use.