we run fire extinguishers on our welder in a busy garage now for well over 4 years no bother, we don't invert the bottles or anything, extinguisher is a male thread so get the reg to suit,some say the weld isn't as nice, i duno, ive not tried argoshield because of the price, they do freeze a bit if you use a lot of gas but because its all thin bodywork we do, the weld runs are never longer then an inch at a time so if your doing heavy stuff you probably need to invert the extinguisher.