It’s a good question. I finished annealing the 4 gauge today and it is in coils so I can try to compare like to like.
the propane torch is really very hot, i sugest you to work on an ambient with low and indirect cool light so you can see the red/vine glow, and after the water phase, deep in acid for 5min.
black = super hot
acid aka, citric acid for food.
i use a cleaning floor solution that have diluted muriatic acid.
The propane torch is far hotter than needed to anneal copper, but I think the bigger issue is the inconsistency in the temperature unless you are moving the torch along the wire at a very controlled rate. Please keep in mind that the thermal conductivity of copper is very high so the wire before an after the torch will have a fair bit of heat conducted into them from the point where the heat is applied. A fairly nasty heat transfer problem - perhaps I should assign it to my senior level students!
You guys have me over here thinking about buying a fire pit and some raw copper wire. 
I ran out of 12 gauge 10 days ago. Of course, right in the middle of the initial styling of a Ponderosa. Argh. I finished the tree and then ordered 500 feet. It arrived on a little spool that I was able to disassemble. The best part of this vol of wire is that the little spool is just the right size for the coil to go directly on the propane burner in the little pseudo kiln (cinder block and bricks) No re-coiling required
Where do you order your wire?
I’ve ordered twice from
I’m not sure if it’s actually cheaper after you factor in time, propane, (danger) but there is a nice feeling when I’m using something that was unusable before. There may be other cheaper sources so if anybody knows of some, please post.
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