dave wrote:

what'll -resist- the arc temperature, not melt, and stay square? getting
the inside ends square again with a tiny jewelers file could take hours....

Forget about copper. It will melt away if you hit it directly with the
arc.
You can use copper if it is underneath the weld and you want / need to
conduct the heat away.
And yes, you can weld copper to steel with an arc. I have done it
(willingly) and it works perfect.
Also, don't you care about the distortion you will get with welding
sheet metal?

A (not so comfortable) suggestion would be tungsten.
Conclusion:
forget it, file it!


Nick
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