Ok I am Installing a fuel Cell in my car so I baught a Lincoln sp-135 Mig. Well the welding I am doing is on .031 Sheet metal and .118 Square tubing, On the .031 Sheet metal I am using .025 Mig Wire and 75/25 Gas, Now what would you recommend for welding the .118 Square tubing, .030 Flux Core or .030 Mig wire and Gas, I know I would get less contamination with mig and gas but some say if it is thicker than 16guage to use flux core. I just need some Usefull knowledge.

Thanks

 

With that size welder it should be rated to 3/16" thick steel using .030 wire and CO mix and not have any trouble producing good welds. One trick i found years ago with mine, when welding thicker material with the same small welder I would switch to .035 and it would penetrate much better on 1/4" thick stuff. You could also opt to buy 100% argon as it will penetrate deeper into the weld as opposed to the CO mix.

Flux will burn hotter at the expense of apperance with slag and spatter.