Efficient melting of metal in the hobby foundry requires a simple, but well designed, easy to operate melting furnace. A well-designed furnace does not necessarily mean it will be expensive to build, or that that is complicated to construct and operate.
If you're just beginning your metal casting journey, there will be a multiple of questions that will need to be answered; and if you follow some simple methods, your learning curve will be dramatically reduced.
A well-built furnace will take you another step along the path to being able to maintain an important piece of equipment for your hobby foundry set up. Without an efficient furnace your hobby metal casting experience could well be one of total frustration & disappointment.
It is possible to build a furnace from scrap materials found around the workshop. This is not to say that it will look trashy or just made, the point being made here is that you do not need to build everything from new materials. The only material you will need to buy is the special high temperature resistant refractory to line the furnace walls with, plus a few brass connectors from the local plumber for the gas feed line and some brass rod to custom-make your own special gas jet for the burner. The rest you can quite easily make yourself if you have metal working skills.
One of the biggest problems the hobby foundry worker has to overcome, is to acquire the knowledge to build a high-energy output burner, the subject of burners can raise many arguments amongst hobbyy workers, and there is a straightforward solution to building an efficient burner, by following simple instructions any practical person can fabricate an efficient burner that will quickly melt metals such as aluminum and bronze without effort. The process to build a high output furnace burner is really quite simple, but there are a few small parts that need to be machined on a lathe.
If you do not have the luxury of a lathe in your workshop, sometimes a friend can help you out. Although, many hobby metal workers do own a metal lathe these days, it is almost a must have for the average home engineer in this ever-increasing DIY age. You will also need a MIG or ARC welder (Max 180 Amp) to fabricate the furnace.
Be very careful with your gas pipe & joint connections, although there are no great line pressures involved with the gas feed to the burner, but any small leak could lead to the possibility of a dangerous explosion.
Propane gas expands between sixty and one hundred times once exposed to air. So be aware, gas is the most efficient fuel you can use to fire a crucible furnace, but it can also be an extremely dangerous material. You need to follow any building instructions carefully and not be tempted to take any shortcuts as they may lead to personal injury.
If you are a resourceful, practical person, you could build your own crucible furnace for less than $ 70.00US, this is a mere fraction of the cost of a commercial unit, and should be equally as efficient, and provide many years of reliable melting service .