Get some scraps of similar guage to test on before welding on the truck..............you can't weld in one place for too long; you have to keep moving.
I have welded some pretty thin metal with an oxy/acetylene set-up without blow-thru............it can be done.
Remember, Torch angle, torch gap and torch speed are needed for a good weld. Tack it all in place, then skip weld (go a few inches, then move to another area; repeat and return). Weld right on through your "tacks" to insure penetration.
Could be your "amps" are set too high.........too many "volts" and you will have "berries" all over.
Practice on the scraps, get you machine dialed-in, then get yourself "dialed-in"...........get in a comfortable position so that you have freedom of movement all the way through the welding area. Use both hands and move steadily across your work..............
You'll be "stackin' dimes" in no time..........
A good weld looks like a stack of dimes, layed over flat.
THere are a lot of books on this and I am assuming you are not a career welder. If by chance you are, my apologies.........
Need more help? let us know.............
What brand of welder are you using? I hope it's a 220v type............E70S6 is a good wire to use along with a Co2/Argon mix............straight Co2 is fine though.
