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Melting Copper
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Author:  mad duck [ Mon 04-28-2008 4:48PM ]
Post subject:  Melting Copper

I've come into a big spool of tar coated copper, and would like to melt it down and sell it.

So I just gave it my first attempt, and have determined that I have no idea what I'm doing.

Has anyone else here come done this before? What should I use as a crucible?

Author:  the naked prophet [ Wed 04-30-2008 11:48AM ]
Post subject:  Re: Melting Copper

You can sell it in spool form to get the money for scrap.



But if you really want to melt it, here's what you do.

You'll need some bricks, lots of charcoal, some small diameter steel pipe (like electrical conduits), a vacuum cleaner with a "blow" setting, and some ceramic/clay flower pots without holes in the bottom.


Build a small square enclosure (about 1x1 foot, maybe 18x18 inches) with the bricks, with a double layer of bricks on the bottom. Leave a space for about four feet of the steel pipe to come in, and bend the pipe (or assemble with elbows) so that there is about two or three inches of pipe sticking straight up into the middle of your enclosure. The last two or three inches of the pipe should have holes drilled around the circumference.

Then fill it with charcoal, leaving a spot for the flower pot, which you put right in the middle. Charcoal should go most of the way up the sides, and the enclosure should be at least one brick higher than that.

Hook up the vacuum cleaner to the pipe, so that it will blow air quite strongly into the furnace.

Light the charcoal, and turn on the blower, it should get really hot. I know for a fact that this well melt aluminum (1250 F) and get hot enough for a pretty nice cast with aluminum. It may melt copper (1980 F) as well. It won't melt steel (2200 F) so you may be able to use a small steel bucket instead of a flower pot, which will probably break (it took several tries before one held together well enough to hold the melt).

Author:  the naked prophet [ Wed 04-30-2008 11:49AM ]
Post subject:  Re: Melting Copper

But let me know before you do. I want to watch. It was really cool with aluminum.

Author:  LostBoyz [ Sun 05-04-2008 1:22PM ]
Post subject:  Re: Melting Copper

I might do this for pure shits and giggles

Author:  Dave D. [ Tue 05-06-2008 8:23PM ]
Post subject:  Re: Melting Copper

I did something quite similar when I built a forge at my house (when I was still at UMR). It'll get hot enough, the best bricks I've found to use are actual fire bricks (I got some discards from the ceramics dept.), almost as good is to get the flat cinder blocks from Lowes. They're made of the same stuff as the regular cinder blocks, but maybe 3" thick. Make your furnace or forge out of that, they're good at insulating, but after 3 or 4 really high heats (like from forge welding) they start to crumble like chalk.

If charcoal doesn't get hot enough, take a very early morning trip to the power plant with a 3 gallon bucket. Start your fire with charcoal and no forced air. Layer on the coal, let it get started, then turn on the air. It'll dump a lot of yellow smoke (sulfur) and then it will start to get hot. Very hot.

If you coke off the coal first (heat, but try not to burn in a low O2 environment), the sulfur and other crap will burn off leaving you with coke (basically graphite). That'll burn clean and hot.

With forced air I've managed to burn tool steel straight through by not paying attention.

Author:  Dave D. [ Tue 05-06-2008 8:31PM ]
Post subject:  Re: Melting Copper

Oh yeah, it might work best if you burn off the covering first.

Then make a paste of water and borax. Smear that on the copper before you heat it. This will act as a flux (does for steel and iron anyways). It will keep the oxygen from binding to the copper at heat, and give you a better product.

(Not a Met, just a CS with a hobby. If I'm wrong, someone let me know.)

Author:  the naked prophet [ Wed 05-07-2008 8:46AM ]
Post subject:  Re: Melting Copper

Sounds right, I had forgotten about flux since I've only done aluminum.

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