help with gmaw bad welding results

When I use flux core wire the welds turn out nice but when using gas the welds are very bad with a lot of small holes in the weld and the contact tip gets a black film on it.I reversed the polarity with the flux core and changed it back with the gas.

I am using pure argon with about 1200 psi but I borrowed a 75/25 tank from a friend and it still had the problem. At first the problem seemed erratic but now it is all the time. I even changed the regulator and it seemed to have gotten worse. I then put new gas hose from the regulator to the gun liner as it was leaking some which that fixed the leak but not the weld problem.

The solenoid works fine and you can hear the gas coming out when you purge the gas line.

I don't think the pure argon is the trouble as I borrowed the other tank 75/25 and still had the problem. I know I should use the 75/25 and may buy a bottle but hate to keep buying and not fixing the problem.The only other thing I can think of is the age of the wire. It is old and so is the argon at 10 to 15 years old. The wire looks good and I even have some stainless wire and it had the problem too!I am at a loss as of what to do next. I think a small roll of new wire to see if that is it and next a bottle of 75/25.

Is there any way the gun liner/hose could be the problem? Will old wire cause this type of problem? Will gas go bad over time? I want to weld inside of the building or I would just use the flux core but it causes too much smoke etc.

Any help/suggestions would be appreciated. The welder is a Snap-on that was made by Century years ago and like I said it works fine with flux core wire but not with gas.

Thanks for any help.

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You need to make sure your set to electrode positive for bare wire so make sure that right before trying to go further.

Also, it is not going to weld right at all with the pure argon no matter what. Even if you get the porosity problem fixed.

I think you have a leak.

holes in the weld indicate contamination of some sort. either in the base metal, wire, or gas.

since you already tried a cylinder of 75/25 and still had problems, it might be a leak or something else.

try to isolate the issue by changing things one thing at a time.

good luck