Just fired up my new welder and realized I don't exactly know how to purge the argon from the system once I am done and want to close the valve on the tank. I've read lots of books on gas welding because I have one of those also and they always say to bleed off any air in the hoses when done and spin the knob out on the regulator to take tension off the spring. In my case, I just struck an arc on a scrap and let the argon flow until it was gone. It got noisy when the argon was done and then I stopped the arc. It's the only way to do that, right? Do I need to worry about that or can I just close the valve on the tank and leave the pressure in there? I weld very infrequently. I am new to this and want to make sure I do everything right without damaging anything. I love the 180. Just took a class and TIG was just too cool. I plan to do some light fabrication in my garage. It's a great welder.