What size and what type of tungsten?

[kenc]

I'm new to Tig, and have a question about tungsten and rod choice.

I'm going to be welding 18-20gu sheetmetal. Should the diameter of the tungsten and the diameter of the er70s-2 rod be approx the thickness of the sheetmetal? So that would be a .040 or 1/16" tungsten and .045 or 1/16" rod?

My rig came with a few sticks of 2% thoriated tungsten. For a good general purpose tungsten used maybe 95% on mild steel sheet and 5% on Al, can I go with a single type - e.g. 2% lanthenated, or should I plan on one type for DC welding and one for AC?
Cheers.
Ken

[Sundown]

I'm new to Tig, and have a question about tungsten and rod choice.

I'm going to be welding 18-20gu sheetmetal. Should the diameter of the tungsten and the diameter of the er70s-2 rod be approx the thickness of the sheetmetal? So that would be a .040 or 1/16" tungsten and .045 or 1/16" rod?

My rig came with a few sticks of 2% thoriated tungsten. For a good general purpose tungsten used maybe 95% on mild steel sheet and 5% on Al, can I go with a single type - e.g. 2% lanthenated, or should I plan on one type for DC welding and one for AC?
Cheers.
Ken

For that thin stuff I would most likely use 1/16" ER70S-6 rod, 1/16" 2% lanthanated tungsten. I have from .020 - 3/32 collets but find that 1/16" or 3/32" will cover most anything from 22ga through 1/4". 2% lanthanated for SS, MS, & aluminum will work great, I like a 20 degree taper with point for SS & MS and a 30 degree taper with about a .020 flat for aluminum ... your mileage will vary that thats what works for me.

[Dan]

For 18 -20 ga., depending on the joint design, I'd use an .035 or .045 filler wire. You should be fine with a 1/16" tungsten. If you were doing stictly thinner stuff, I'd be tempted to give an .040 a try though. BTW, this is all based on steel, I am not an aluminum guy. Can weld it, just don't have a use for it.

[TozziWelding]

If you can controll your heat a 3/32 2% can do just about anything.