A propane forge is a system that uses propane gas to create a flame that is then contained within a barrel or other containment system. The purpose of this propane forge is to heat metals until they are malleable for metalworking and shaping. Unlike a coal forge, which is the more traditional type of metalworking system, the propane unit will be much easier to use for beginners, and the heat will be regulated much more easily. There are drawbacks to such a system, including the inability or difficulty to heat only a small part of the metal object being worked.
The size, shape, and function of the propane forge can vary from the very simple to the much more elaborate. Generally, all forges feature three major components: a propane tank or fuel source, a burner, and a barrel or containment system. The cylindrical propane forge barrel is often lined with some sort of material that can resist damage at extremely high temperatures; ceramic is a common lining choice for a propane forge cylinder. The burner extends into the barrel to provide the fire source, and it can heat the inside of the barrel fairly quickly.
Fuel is provided to the burner by a hose connected to the propane tank, which is a large metal tank that contains the gas. In some cases, a feed line is used instead of a propane tank, as the tank may not be large enough to contain the required amount of gas for the metalworking project. Professional metalworkers will instead connect the burner directly to a gas line piped in from an outside source. This prevents the cylinder's temperature from dropping unexpectedly due to an insufficient feed of gas.
One end of the propane forge cylinder will feature a door that can be closed to help heat the inside more quickly, and opened to allow the metal worker to insert a piece to be heated. Once the metal is malleable, it will glow red-hot and it should be removed from the cylinder using tongs. The metal worker can then place the piece on an anvil or other shaping device. Hammers and other tools are used to shape the metal into the finished product. The piece may need to be re-inserted into the cylinder numerous times for re-heating before the final shaping takes place. The metal is then cooled and hardened into the final shape.