Weld metal supports to the bottom of the water heater, so it will stand on its own. The water heater must be stable so the lower vent can open and close. Cut a hole halfway up the water heater, using the propane torch. Make it slightly larger than the copper pipe diameter, so you can fit the pipe through the heater's side.

Insert the pipe and weld it in place. Make sure the pipe end extends out from the side of the water heater far enough to attach the air compressor hose. The air compressor hose must be a minimum of 2 inches away from the side of the water heater.

Assemble the propane gas line to the propane tank and flame spigot. Turn on the tank valve and light the flame spigot. Insert the flame spigot through the water heater vent, and ensure the propane flame is directed toward the interior of the water heater. Preheat the interior of the water heater for 3 hours, before continuing.

After the interior of the water heater is preheated, turn off the valve to the propane tank, and remove the flame spigot from the interior of the water heater.

Turn on the air compressor, and place the air hose on the copper pipe running to the interior of the heater. Ensure that a constant flow of air is flowing through the copper pipe.

Place charcoal around the bottom of your aluminum smelter, and light the charcoal on fire. Continue adding charcoal, until the flames reach the height of the copper pipe. The flames must remain at this height while you smelt the aluminum oxide.

Slowly begin adding aluminum oxide or alumina to the interior of the water heater. Make sure you do not add too much -- putting out the fire created by the charcoal. As you add charcoal, adjust the air flow to the interior of the water heater to maintain the flame height. The ore will begin to melt once the temperature reaches the range of 920 to 980 degrees Fahrenheit.

Aluminum slag will begin to form on the sides and bottom of the water heater. Scrape away the aluminum slag from the smelter. The aluminum slag removed will harden as it cools.