every MIG welder I ever used, the gas-flow regulator was adjustable from Zero-up ... simple glass-tube 'floating ball' gauge ...

interesting side-note: reading an interview with some 'famous' breeder (forget which one) he stated that CO2 was the 'last' thing to worry about ... he stated that CO2 only helps, IF everything else was spot-on perfect ... using that logic, I assume I will 'never' be worrying about installing it ... I use the simple water/sugar/yeast bottle ... may not help much, if at all, but is cheap and easy ... that's me, 'cheap and easy' :S2: