3m Panel Bond instead of welding?

[m16ty]

Untrained & novice mig welder here, but I've watched the experts on TV use .24 wire on thinner sheet metals. I welded in an 18 gauge patch this weekend outdoors with my Miller 211 using .24 and didn't have any trouble with burn through, the wind was a little breezy. I set my gas output to about 30psi, which I knew was a little high but I figure it didn't hurt outdoors.

I usually run .30 wire in my Miller 251. It seems to do OK with all but the thinnest material and can also go 1/2" thick or more. It seems to be a good all around size. Just slow down and run cool on the thinner stuff and speed up and run hot on the thick stuff.

From your pics it looks as if you are running a little too cold on your tack welds (not much penetration and a humped up a lot.