Thanks fellas. Maybe shoulda asked a different ?

I run a cute handy little 100a/110v Lincoln here too with argon/co2. It puts down a noticeably hotter and better looking weld than that 135 Miller at work. Both of the mig at work are co2 only so that's maybe the whole reason my dissapointment with them. Remember I'm pretty new at welding. Hmm. didn't tell you that did I. 2 years getting paid for it. I'd like to keep the R3S if I had power but won't afford a huge expense to run it inless I can really make it pay.
Guess I should know how thick a weld joint I should keep .045 at too. I'm thinking 1/2" is work with .045??
Probably getting myseldf more confused here.

Well sure you can't compare a Ar/Co2 mix cover gas to straight Co2. The Ar/Co2 will leave less spatter, have more pentration and a smoother face.

Any time you have a manual welding process over 3/8" in plate thickness, you need extreamely fast eyes and even quicker hands as your rolling a huge ball of melt. If this was a every day weldment occurance then you would get used to the fast pace that every thing happens at and make a decent weld every time.

Problem is unless thats in a production enviroment, most weldors will never be able to handle that kind of puddle in one pass. Weldment quality would greatly suffer with alot of rejects. Multi-pass welds however would pass inspection every time.

To comment on the joint Tony refferenced, when I was at Coors we would tack weld the 3/4" plate, roll, then tack weld again with 7018 or manual Mig, then I would run a single pass with SAW that used a .125" wire with about a 1/4lb of flux perinch of weld.

SAW (submurged arc welding) is very close to Mig welding, with a very large electrode wire and a granular flux.

T_Bone

Tony, not sure why you told me that except for the "pick the right way to make it a good weld" story. Guess the whyfer's are losing me. Loren

The below list was made for SS but in theroy can be appiled to all common metals:

Pure Argon with Mig works well on light gauge SS SM as it gives lite penetration and reduces weld splatter. Argon adds arc stability with shallow penetration, lowers weld spatter and removes oxides at the weld surface.

Helium adds high thermal conductivity with-in the arc reducing it's density. Read this as a cheap(free) amperage increase. Increases penetration and flatens the weld bead contour.

As we move to heavier SS metals we can add 1% to 5%, o2 with the Argon that helps with undercutting and adding penetration for Mig welding. Adding more than 5% o2 would cause porosity with-in the weldment.

Qxygen in amounts upto 5% can be added for broading the penetration in the center of the weld bead, controls undercutting and helps improve arc stability.

Co2 can be added but has a spatter problem on most thin gauge metals and defeats my useage. O2 on the other hand enhances the tri-mix.

When Helium is added with Argon, 75%Ar/25%He the weld bead is broader and penetration is improved on SS.

Then we can add Co2 with Argon for a mix of 75%Ar/25%Co2. The Co2 is primarly added to reduce the cost of pure Argon. We can also use pure Co2 for some SS types but weld splatter is a big problem.

Now we get the best of all worlds and end up with a tri-mix of Argon/Helium/Co2. With this mix we get the flatest weld bead profile, good penetration and very little weld splatter on SS.

We also can use a heavy consentrate of Helium and add Ar, Co2 or o2 for Mig welding SS.

What determines the cover gas, is the composistion of the filler wire and what the filler wire mfg spec's.

These cover gasses can also be used for welding other metals.

T_Bone