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I’d give it a go if that’s what you have

Clean it after welding it, just use emery where you want to weld. If you heat it and quench it most of the scale will fall off.
Are you after function or form? As in are you wanting to clean it up...

40mm Normal household vinegar will do the trick after a quick buff with a wire brush.

P.S. if you need a stick or two of 15% sending up give me shout.

Copper tig welds really well, but welding with silfoss will be fine. If you get it hot enough in use to melt silfoss you’ll have other problems to worry about.