Thanks. Not the sort of thing you want to get backwards.
I've got a Unispot [-like] spot welder. I've been thinking about using it to spot weld corrugated sheet metal and Cyclone fence top rail. Bottom of the corrugation to top of the pipe. I've been using pop rivets, but when you take things apart it leaves holes. The spot weld might come apart with a chisel.
I could do a test and report back.