Hey Brad, just saw your post on IG about a stainless steel replacement tank project. I'm curious if you can provide some details like the thickness of the material, basic settings and if you back purged. I'm been trying stainless without back purging, and have gotten some decent result by using lower amperage so that I don't get full penetration. I don't believe full penetration  is needed for strength on a tank. I was hoping to get some confirmation or good advise for stainless steel tank welding. 

Thanks JD! Your Mop Tub video came out right after my post and was very helpful. Makes sense to purge the whole thing. Thanks again.

Francisco SotoI too use a #5 stubby with 3/32 tungsten. I find extending the tungsten a bit more than the 5/16" recommendation helps with visibility and gives a bit more room for feeding the filler. Since the tee traps the argon, the gas coverage is good with the normal setting of between 5 and 10 CFH.

I recently had my first bottle of bad Argon. I was welding round aluminum tubing and had the setting and techniques pretty dialed in. I changed the bottle and part of the weld was terrible but part was reasonable...so confusing. I have two bottles so I switched them out, which resulted in nice consistency.  I brought the 'bad' bottle back to AirGas and they swapped it out, no charge or problem. When I used this bottle, everything was good. 

To answer your question, the only way I know is to switch bottles...

Very interested. If or how you purged the back side would be helpful. I’m guessing if you didn’t purge the back, maybe you set for less than full penetration welds. Discussion of this your be helpful to me, thank you.