[Least honorable]

Hello, I am planning on making my own welding cart and I was wondering until what thickness does the rule of "1 amp per 1 thousandths" apply? And at what amperage should I weld 1/8 thick 1x1 square tubing at? Using most likely 70 s-2 I will also be welding a 3/8 piece of plate to it so I assume I would bump up the amperage and stay on the thicker piece more than thinner?

PS: the square tubing must hold up my 70lbs machine, and about 150lbs for the argon bottle.

This is my second time tig welding as well as my second tig project and I would appreciate any extra tips in order to help it go smoothly

Thank you for your help

Regards

Noah

[exnailpounder]

Jody states that the rule of thumb on amperage is good up to .125 or so. I always go 10 amps or more over the rule just to have a little more power available. It's always best to do a test weld first on some scrap rather than ruin your piece. Jodys rule will usually get you in the ballpark no matter what thickness of metal you are going to weld but you have to tweak it and more often than not, it means more amps than what the rule would suggest.
If I was welding 1/8" square tube to 3/8" plate I would set up at about 160 amps and definitely favor the thicker metal but not much. Welding different thickness metals is all about pedal control. When in doubt, practice on some scrap.

p.s. God makes paint to make ugly welds prettier

[MinnesotaDave]

I think you'll be happier in the long run if you practice first.

Practicing on actual projects can lead to frustration and grinding - no one likes grinding

Perfect your t joints, and thick-to-thin t joints.
Also, practice welding square tubing as the corners tend to suck a little more heat then the rest of the tube.

One tip for tacking - a quick burst of high amps will tack items together without filler.
It's fast and allows you to tack with one hand while holding metal with the other.

[Least honorable]

p.s. God makes paint to make ugly welds prettier

Haha, thanks for the help, much appreciated