DIY furnace bodies are typically cylindrical and made of metal. Depending on the size of your furnace — which you can determine by the volume of metal you would like to melt — you can use metal cans from bulk food purchases, or a stainless steel crockpot. Kaowool (a ceramic fiber with high-heat resistance) is an ideal lining for metal melting furnaces. [1] X Research source Crucibles are the container in which you will place the metal scraps to be melted. The liquified copper will pool here; it is necessary that you use a material that will not melt or crack at the temperatures needed to melt your copper. Clay graphite is a common choice. [2] X Research source For the propane burner, you do not want something used for cooking, but instead a torch-like fixture to position through the foundry exterior and by the crucible. These are widely available online. The lid will be fashioned out of a smaller top portion of whatever you choose to be your foundry body. Foundry lids have a small hole in the top that allows for ventilation and the prevention of dangerous pressure build-up.
Double push up furnaces rapidly heat metal in individual “shots” or rounds. The advantage here is that you can start and stop your process easily and not waste energy when only melting a small amount of metal. Tilting furnaces are often used in industrial settings. They continuously melt large amounts of copper and are automated to pour into a ceramic container or any desired metal cast/mold.
Originally metal workers used charcoal and coal. Presently propane and natural gas are used because it saves time and allows blacksmiths to focus on their work. One downside of charcoal is that it gives off harmful smoke and will require more attention in maintaining proper temperature.
Bulk canned foods (such as peaches and soups) can provide a metal can of the proper size and shape for your DIY furnace. For something larger, stainless steel crockpots can also be easily converted into a foundry.
Kaowool is made of a blend of alumina, silica, and kaolin.
ITC-100 is an infrared reflector which will send back up to 98% of the heat that touches it. [5] X Research source coating used inside of kilns and elements. Using this can help protect your kiln, and also save fuel. Satanite needs to be mixed with water until it forms a pasty solution, and then painted onto the kaowool with a brush.
The entrance should be angled down at roughly 30˚. Should any metal fall from the crucible (or should the crucible break), this will prevent any dangerous material falling into the propane tube. The circumference of the hole should be only slightly larger than that of the propane burner, so that is is held securely in place.
Once the burner is safely attached to your propane tank, slide it snuggly into the pre-drilled entrance. Do not insert the burner completely through the hole. The flare should be 1. 5in. from the chamber center to protect it from high-temperature damage. [6] X Research source Always keep your propane tank’s valves closed when not in use.
If you would like to make your own crucible, you can repurpose old materials like fully used fire extinguishers.
Copper is used to make wires, electronics, appliances and motors, and is therefore commonly found around the house. You can find copper in cookware, furniture, wires and pipes. Appliances that utilize copper include air conditioners, dishwashers, heat pumps, freezers, refrigerators, washing machines, clothes dryers, garbage disposals, dehumidifiers, and stoves. Decorative and utilitarian items can also contain copper: fire screens, large clocks, bells, jewelry, etc. Be aware that it is illegal to melt U. S. pennies or nickels. [8] X Research source
This may involve either light or heavy-duty trucks, conveyor belts, and potentially stationary or mobile cranes depending on the scale of you operation. [9] X Trustworthy Source US Occupational Safety and Health Administration U. S. government agency responsible for setting and enforcing workplace safety standards Go to source
Be aware that this process can create a serious safety hazard. Flying pieces of metal quickly become a physical threat. Make sure this process is performed in isolation. Anyone near the operation should be protected by appropriate blockades, walls, etc. to ensure they will not be struck and/or injured.
Always wear a face mask to protect yourself from burning debris. Copper has a high heat-resistance and can be difficult (though not impossible) to cut with a gas torch. Plasma torches and powder cutting torches are often used when cutting super-conductors like copper and bronze.
Always wear heat-resistant gloves and a face guard when beginning the actual metal melting process.
