Hobbies And Interests
Things You'll Need
Instructions
Prepare your scrap copper by cleaning it of debris and insulation as much as possible. Burn off any remaining insulation in a small outdoor fire. Use a hacksaw and wire cutters to cut scrap copper into the smallest pieces possible. This increases surface area and speeds up melting.
Place the cleaned and cut scrap copper pieces into a graphite crucible, which has been properly cured by preheating to at least 500 degrees F and cooling one or more times. Add one ounce of borax powder for each pound of copper in the crucible to serve as a flux to aid melting. Cover the entire crucible contents with a 1-inch layer of fine charcoal powder, which helps remove impurities and retain heat to ensure faster and more even melting.
Place the filled crucible into a coal- or gas-fired blast furnace or kiln either outdoors or in a very well ventilated indoor area. Increase the heat of the blast furnace by increasing air flow. Continue heating until the copper begins to melt. Copper melts at 1,985 degrees F; furnace or kiln temperature must reach and slightly exceed that temperature. Continue heating until the copper is thoroughly melted and any charcoal residue has burned away. Wear a welder's mask or goggles to protect your eyes from the brightness and from any fumes or splatter.
Wear thick heat-proof gloves to handle the steel tongs. Use the tongs to remove the crucible of molten copper from the furnace or kiln. Carefully pour the molten copper from the crucible into each of the graphite ingot molds. Allow ingots to cool naturally. Do not immerse in water. This may take several hours.
Remove copper ingots from the molds by inverting and tapping gently with a wooden mallet. Use a wire brush and a sudsy ammonia detergent to soak, scrub and shine the new copper ingots. Snip off any excess copper sprue or overflow with wire cutters for recycling in your next batch. Use a dry terry cloth rag to give your copper ingots a thorough buffing.