This is a very quick and easy project that will help you decide if you want to melt metal.
Materials for the furnace body:-
1 x coffee can (or a container roughly that size)
1 x K26 fire brick
Some Kaowool hardener, (or a something to seal the Kaowool)
4 x 1/4" coach bolts
8 x matching nuts
To power the furnace you will need a Bernzomatic hose torch, this is the most expensive part, but can be used for other jobs, so if you decide you don't like melting metal you will have a very useful torch for your tool box.
To use the furnace you will need a thimble crucible, and this is necessary as it is used to determine the internal cavity of the furnace. Fortunately these are relatively cheap.
Your standard K26 fire brick is soft, and can be sawed, and shaped easily.
I cut the fire brick in half for the furnace body, and with the other half I cut that in half again to act as a lid. I drilled a hole in the centre of the lid to act as an exhaust. You will have a piece of K26 fire brick left over, just store that someplace as a spare lid.
I used a 1/4 inch drill bit, to carve out the cavity, and used a piece of masking tape attached to the drill bit to act as a depth gauge. A drain was drilled in the bottom, and a hole for the torch tip was drilled in the side at an angle. The torch inlet was positioned at the base of the furnace cavity. (See photo 2).
Four holes are drilled into the coffee can, the coach bolts, and nuts are fastened. Drill a hole in the side of the can matching the torch inlet in the fire brick. Jamb the firebrick into place, you may need to take off the corners of the fire brick if the fit is too tight.
Pack the fire brick into place with Kaowool. Apply the hardener to the exposed Kaowool. Remembering to put some hardener into the torch inlet with the tip of your finger.
Wait until the next day and your furnace is ready to run.
Initially I designed this furnace to melt , and alloy bronze, however I have melted silver and gold in it successfully. It doesn't have the ability to melt platinum or steel.
Others have used my design and used a hand held propane torch instead of the Bernzomatic hose torch.
Have fun melting metal, and remember molten metal is very hot, so be careful.