New Old welder: weld 1, grind 2!
 

Greetings from sunny Florida! Trying to learn to Mig weld sheet metal as in auto bodies, old bodies. Presently attempting to repair the rusted out sections of a 1949 Studebaker Truck. Having big problems with burn thru when joining different gauges of sheet metal. I am using ESAB .030" easy-grind wire. Willing to read, practice and learn. Thanks for this forum!:cool:

Question: Do you need to use different gauge metal for any particular reason?

If you do, then you will need to aim the gun more at the thicker piece to concentrate the heat more in the direction, and only "pull" the thinner metal into the puddle as it forms. You'll move the gun toward the thinner piece to get the puddle to form on it, and move it back toward the thicker piece repeatedly. It takes a bit of practice, but you'll get it. I find the most important thing is being able to see what the puddle is doing, so make sure you use a good helmet.

First let me say Welcome Wally!

If you have to mig weld sheetmetal try using .023 wire :)

Wally: Welcome to AllMetalshaping. I am also located in the Ocala area. Ocala address but west of Anthony.
I have to admit that MIG is my least favorite method of welding. I have difficulty seeing where I am going particularly on flat welds. Old eyes. Are you trying to run a continuous bead? If so, you might try a series of short welds giving the base metal a chance to cool a bit. If you are already doing short welds, maybe take alook at your welder settings.
There are people on this forum that are pro welders that may have further or better advise.
You might even consider a copper back plate to dissipate some of the heat.
Carey Culpepper
I am in the phone book, if you want to chat.

Hi Wally, welcome to the site. I am guessing you are not talking about butt welding two pieces but rather welding a heavier flange to a thinner gauge panel? if this is the case I would suggest plug welding rather than welding the edge. - Perhaps some photos of what you are doing would help.

David

weld metal
 

Wally
You can weld different gauge sheetmetal with 030 mig . practice on some scrap pieces . If you can, post pictures showwing of what your working on .
Larry

if its rusty, i would go with .023 flux wire and use gas too....

Wally, Welcome to the site.

I'm not sure what Esab "easy weld" wire is, but if it's flux core, you might want to think about changing it out to .023 solid wire and use C-25 gas. You'll get much better results with the smaller wire as it doesn't burn as hot as flux core. I hope you're stitch welding the panels instead of trying to run a solid bead. Stitch welding is the process of making repetitive spot welds in opposing parts of the panel. This keeps the heat down, helps decrease panel warping, and lessens the chance of burn through.

Good luck with your project and if I can be of help, please let me know.