To melt copper with propane for craft purposes, you will need a gas-powered furnace designed to melt amounts less than 500 grams. Copper will melt at about 2,000 degrees Fahrenheit, and you want your furnace to reach that temperature in about five minutes. An advantage of using propane instead of other fuel sources is that propane burns more cleanly.
Things You'll Need
- Propane furnace
- Safety or welding goggles
- Flat iron pan
- 5-gallon bucket
- Dish detergent
- Powdered charcoal
Connect your propane torch to the access port on the furnace. Then mix a cup of water with a few squeezes of dish detergent. Take a rag and dab the water onto all of the metal fittings through which gas travels. Any bubbles mean that you have an air leak. Tighten all couplings to remove air leaks before moving on -- propane is highly flammable in a mixture with air.
Set your mold on a flat iron pan. Put on your gloves and goggles.
Turn on your furnace. Add copper pieces to the crucible, and put the crucible and mold on the iron pan to preheat it to at least 100 degrees Celsius and start heating the copper. Ensure that the pan is completely dry when you put it into the furnace.
Remove the mold using the tongs when the metal starts to turn a dark red.
Observe the copper as it heats to estimate the temperature at that point in time. Metal will start to show a dark red light at 480 degrees Celsius, becoming an orange-yellow at 1,100 degrees; at this point, you're very close to the melting point of copper.
Remove the crucible using the tongs. Turn the crucible to pour the liquid copper into the mold. As the copper solidifies, it wil take the shape of the mold.
Tips & Warnings
- If you put a teaspoon of borax into your liquid metal before putting it into the mold, the borax will eliminate debris and oxides. For copper, you'll also want to add powdered charcoal to keep the metal from oxidizing.
- Because of the extreme heat that you are dealing with, do not attempt this project without the correct gloves, goggles and tongs. Keep cold water close by in case of spills.
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