[header] How to build a metal melting furnace for casting [title] Determine the size of the furnace for your needs. [step] For casting a small item such as a hand print or other object weighing less than a few pounds, a 12 inch (30. 5 cm) burning chamber with a 1 quart volume crucible should work. [title] Choose materials that will withstand the flame temperature of your fuel. 
[step] We are using charcoal here because it is readily available and inexpensive. It has a flame temperature (heat value) of about 2 , 300 ° f (1 , 260 ° c) with a forced air blower.