Mig or tig, Which would you choose? Options

[r_towle]

Lots of sheet metal body welding, flares, patching, several cars.
I did use a mig for years, upgraded to gas mig.
My son took it.

So, I’m getting another welder.
I still have a gasless mig, and a scratch start tig
Neither are very good.

So, which would you choose? Why?
Willing to take the time and learn.

Rich

[nathanxnathan]

I think where/what you need to weld is the deciding factor. If for instance you have 2 layers, there's going to be oxidation and old primer between, and tig doesn't like it.

I've been working on a front cross panel replacement. A body shop had done a rotten job of not only installing a replacement piece, but also taking off the original accident damaged piece. Here's the area around the bumper bracket where they drilled the spot welds.



I tried to tig the holes, but the contamination was a nightmare. It kept blowing up and messing up my electrode. I had to grind out the porosity it caused trying to fix the bit at the corner. Once it gets contaminated, you have to grind it all out. The bubbles will mess up any weld you try to patch it all with. There's just no way to fix this with a tig without drilling the spot welds to remove the whole bracket, and getting it to a single layer that you can clean behind..

I ended up using the mig. Mig doesn't care, just power through, grind them down, burnish and it's good.



For clean work, tig rules. The replacement cross panel I got was pretty rough itself. The end was missing, went with the fender to a different car. And the inevitable damage of removing it, fixing those holes in prep for spot welding it back in, tig is so much more controllable and the weld is more workable.

Here's the inside driver side of the replacement panel where I started.


Then bead blasted, holes filled, planished, burnished, treated with Oshpho. The end of the previously installed panel is Frankensteined to it. This is the front of the same part after.


If you can only get one, I'd say the mig is more versatile.