If doing tacks adjacent to each other it's not an issue after a couple of tacks have heated up the panel. But if you have pin holes to fill, heating up the area to a couple hundred degrees makes that one spot weld lay down a lot flatter.
The spray would mainly just help to keep the steel from attaching to the copper, same as it does for copper MIG nozzles and tips.
Just used a copper bar last night, putting in a big patch on my floor board, worked well for an area that was thin and would have been a real pain to slowly build up with wire. Held it in place with one hand, welded with the other.
Out of my four welding machines ... the 30 year old little Lincoln MIG with .023 is still the best for this kind of work, that machine just won't quit.
Passenger side done, working on the driver side now.
Last edited by dataway; 12-11-2020 at 11:11 AM.
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