Gaps for sheetmetal welding

[Mathius]

Okay, I've read and seen several different "opinions' on welding sheetmal when it comes to gaps between the two pieces.

I've been trying to cut and fit the pieces nice and snug together (very small gap, less than the wire diameter) and doing the individual tack/stitch weld technique. I was told that by having a nice tight fit, I would have less warpage issues....

Then other times I see people saying there should be a gap between the 2 pieces that is the same thickness as the metal you are welding. That just seems like a big gap to me when I'm working with 18-20 ga....... I guess the benefit is that the weld bead will be lower and require less grinding etc and insure full penetration etc...

Rihgt now I'm doing rust repair in future "hidden" areas but plan on doing fender patches etc, so I want to make sure that in the long run, I do it the right way for a good long term repair

There's no right answer for this. Depends on thickness of material, wire size (or filler rod size), etc.

Mathius