Copper wires are regularly uncovered during construction work on old homes, bridges and highways. A lot of this wiring, thick and thin, gets thrown away, buried or sold for scrap. When melted down into a bar, the copper wire has the potential to increase in value as well as be easier to transport.
Numerous techniques can melt the wiring into bars, which needs to be 1,985 degrees Fahrenheit (1,085 degrees Celsius) to liquify. An oxyacetylene torch or kiln are the most reliable heating elements, yet some more adventurous metalsmiths use a stove top or furnace.
A few caveats exist for all of these methods. Burning off the plastic insulation or cover is bad for the environment. Whenever possible, trim it to remove before heating. Use proper protection such as goggles and heat-proof gloves to be safe.
Things You'll Need:
- Copper wire
- Oxyacetylene torch or kiln
- Crucible or other heat-proof vessel
- Bar molds
- Ammonia detergent
Clean your wires of insulation using wire cutters. While it's possible to burn off this sheathing, this technique isn't safe for you or the environment.
Twist the wire into coils that will easily fit inside the crucible or other heating vessel being used. Place the wire in the crucible to prepare for melting.
Turn on your heating element. If you're using an oxyacetylene torch, put on safety gloves, open the gas, spark the flint and adjust the oxygen to increase the flame to the proper temperature. Point the flame at the wire and move it back and forth to evenly melt the wire. It may be necessary to tip or shake the crucible to heat any unmelted shards or scraps.
Metalsmiths who are using a kiln should heat the furnace hot enough to melt the copper. Handle the crucible with tongs when placing the wire in or taking it out of the kiln.
Once the copper has started to melt, place approximately 1 teaspoon of Borax into the liquid to stop oxidation.
Thoroughly melting the metal may take several minutes, depending on the heating method. When smooth, pour the liquid evenly into the bar mold. If the melted copper starts to thicken during pouring, reheat as needed. When the molds are full, allow them to air cool and remove the copper bars from the molds.
Scrub the copper bars with ammonia detergent to improve the shine.
- * Wearing heat-proof gloves and goggles or a welder's mask is a good way to stop burns from melted copper.
* Experience with an oxyacetylene torch or kiln is a prerequisite for safely completing this project.
Neil Gladstone's writing has appeared in The New York Times, USA Today and Popular Mechanics. He's also the co-founder of the DIY community CraftFoxes and The Craftys, awards for makers and crafters.