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I Forge Iron

Safe way to melt scrap copper, propane forge?


Bill in Oregon

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Copper loves oxygen and turns into a metallic sponge if allowed to overindulge.  Borax for flux or melting under a layer of powdered real charcoal---NOT BRIQUETTES!---can help as well as stiring with a chunk of real charcoal that is DRY DRY DRY.

 

If you are not used to casting please read up on safe handling as I consider molten metal much more hazardous than hot steel even when the steel is hundreds of degrees *hotter*.

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Lump charcoal with forced air is a lot easier than propane, at least to start.  In addition to flux, you can put a lid over the crucible, helps cut down on oxygen getting in. I've done it with propane using a naturally aspirated t-type burner, but although they're easy to make, they can be tricky to get working and dialed in right.

 

Google the Gingery coffee can furnace or the 2 bucks crucible furnace. It's a relatively easy design and you can go a little larger by using a 3 gallon popcorn tin or 5 gallon metal paint can.

 

Don't mess about with homemade crucibles, get graphite, or one of the fused silica ones. Homemade refractory or clay ones can come apart on you, and molten metal HURTS!  

 

And possibly most important, try to find someone else that casts. It'll put you way, way ahead on the learning curve, and it's easy to make mistakes, some of which are dangerous. Don't trust everything you see on youtube.

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Great advice guys. I have been casting bullets for years, but lead, at 620, is much less scary than copper at 1980. Thanks for jogging me on the Gingery furnace, as I have a couple of the books.

I also have done the vast majority of my limited smithing on a Tim Lively charcoal washtub forge with a Champion hand-cranked blower. I really miss that set up.

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Thomas, a few years ago a friend gave me a large copper electrode plate -- or so he called it. It was probably 3 by 10 inches and perhaps a quarter inch thick. I had a lot of fun cutting off chunks and forging/annealing things out of it. It gave me a deep appreciation of copper, and I have been collecting scrap wire ever since -- not much, but enough to support many more small and pleasing projects.

I have also long wanted to attempt to make bronze and pour some simple things inspired by bronze Age artifacts. Being able to melt my copper and alloy it with the tin I have at hand intrigues me.

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  • 4 months later...

The other way to turn wire into usable material is to scrap the wire for $$, and take those dollars and buy good, clean sheet/plate/bar stock.  You will get a consistent product without the hazards of molten metal/fumes/expense of melting.  That's what I do.  Also, remember a cast ingot is not the same as rolled stock, and might crumble when hammered.

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  • 2 weeks later...

I melt copper in my forge no problems. I use old electrical components and wire as well as salvaged MIG welding tips and oxy/fuel torch tips. I don't use charcoal but I do flux with borax. Going overkill with the borax tends to carry over the pour and cause inclusions in my castings, so I've had to find a happy medium by feel. I built my forge to burn propane (atmospheric), I just tuned the oxygen out as much as possible. Here's a pic of what it looks like, works fine for me. I use fused silica crucibles and often forge my ingots into copper bar stock for making copper nails and roves for boat builders. Never had a problem with spongy or porous castings, and I cast in sand.
As usual your mileage may vary. It's always best to take advice and then run with it and figure things out in practice.

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Yours
      - Rusty

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I cast copper and bronze and I use broken brown beer bottles for the flux. They provide a nice O2 barrier and I am told the iron in the glass attracts impurities better than other colored or clear glass.

 

As for the copper itself, I have had good luck with thin and thick wire, with roofing copper both shiny and brown with patina and even somewhat dirty copper.

 

I have had good casts come from all of it.

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