How can I tell if I have a bottle of bad argon gas? I was using the same settings and same bottle of gas when tig welding aluminum. Then I started getting no cleaning action. It was if I was using Direct Current instead of AC. Which I have acidentally done. 😅 . The pressure in the bottle dropped to 8 KPA & 1,250 PSI. I got it from lindell gas 

        I am doing padding on a flat piece and also a T-Joint with 1/8 inch aluminum, ER 4043 ROD, I change the tungsten from 3/32 to 1/8. Running 125 to 150 amps. Using Grey band tungsten.