Spot welding with MIG

[mongobird]

Eastwood has a nozzle for a Tweco style MIG torch, which appears to have two tabs which provide spacing of the nozzle from the sheet metal to be spot welded. They also sell some locking pliers which clamp the two pieces of sheet metal together.

Having a recently acquired Multimatic 200, I was thinking I could fabricate an overlay cone, with two tabs made out of a piece of hard copper tubing, which would provide a fixed spacing from the surface to be spot welded.

The MIG torch on the Multimatic 200 is a Centerfire 1200B nozzle, and I picked up several spares when I bought the torch figuring I would somehow mung something up, and needed spares. But rather than modify one of those nozzles, it appears that a cone could be made to fit over the 1200B nozzle, and providing the spacing tabs.

Has anyone done this? Is there a better way?

Also, I am thinking I could hammer flat a piece of hard tubing, or perhaps a nearly flat spoon out of a piece of copper tubing, to back up the weld, where I might have a drilled out hole I want to fill. Any thoughts on this?

[ryanjones2150]

Spot welding with MIG

Eastwood also has some neat little copper backing plates for what you're asking to do. H80N posted a link to the video in the "raunchero" thread under motorsports. Probably on the 6th page.

[Cgotto6]

Yep you can get the copper backer spoons from harbor freight even.

Once you get the hang of mig welding you will see there is no need for a "jig" to position the torch. You will simply hold it and do it. I would definitely rather have a good view of the puddle, and brace my hands with my elbows or something.

[cwgrizz]

As to your question about using copper tubing smashed flat for a backing strip/plate, I have done that in a pinch and it works fine. Still have a few hanging around for when needed,