Posted by gmharris [71.105.35.169] on Monday, March 11, 2013 at 22:47:34 :
In Reply to: Re: Metalurgy question posted by Denis [69.250.170.223] on Monday, March 11, 2013 at 19:31:33 :
You can't get copper red hot, it will melt before then.
One thing they do on aluminum, and I think it should work on copper. Take a smoky acetylene flame and lay down a layer of carbon black on the metal. Then heat the metal enough to burn off the carbon black.
I've also heard of the trick of filling the tube with sand. But, I might try inserting one of those springs they use for bending tubes. You may not be able to find one big enough, but I bet you could find a suitable spring somewhere.
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