Bought a new welder, ?\'s on gas bottles. First off I just bought a Lincoln Squarewave 175 Pro. It will mostly be used for mild steel and ocasionally alum or stainless. Ive been told to get a 92/8 argon mix. Does this sound right? Ive never tig welded before so i want to be sure. Second, what size bottle should I get? This will be used as a personal use welder. (no major production) Is it better to buy or lease? What should I expect to pay to buy or lease and for refills? Thanks for your help.