It works differently depending on which mob is running the gases mafia in y= our area. Where I live, only one size is "customer owned", all others are r= entals and have collars with a name on it. There is no refilling. You swap = tanks at the gas supply house. If your tank has expired, swap it at the sam= e place you got it, no extra charge for recertification. Rental tanks must = always be swapped at the named supplier, of course. My "customer owned" argon tank costs under $70 to swap ($45 + taxes and fee= s). I forget the size, probably 120 to 160 ft^3, it's about 5 ft tall with = its cap on and 9 inches diameter. I could probably shop around and get a be= tter price but I'm not a big customer so I go to the place that is nicest t= o me. CO2 is another story, it's cheap and easy to swap since both the beverage a= nd marijuana supply places service CO2 as well as the welding supply. Friendly regards, Bob ________________________________________ From: piclist-bounces@mit.edu on behalf of John G= ardner Sent: Friday, November 3, 2017 1:37 PM To: Microcontroller discussion list - Public. Subject: Re: [EE] Vacuum plumbing If you buy a tank you need to be aware of the manufacturing date. Theoretically you can get them re-certified, for about 3X the cost of replacing the cylinder... Last time I looked, anyway - It's been awhile. On 11/3/17, Denny Esterline wrote: > As luck would have it, I just bought a welder for my shop and I still hav= e > the receiving paperwork on my desk.... > In Tucson AZ, USA. I bought two 125 cubic foot rated steel tanks for > $196.10 US each. > One filled with 75% Argon, 25% CO2 - the gas cost an additional $19.23 an= d > the other filled with "pure" argon which cost an additional $17.89 > As this is sold as welding shield gas, I'm going to assume "pure" is abou= t > 99.999%. > > > Man, I really need to clean off my desk. > > -Denny --=20 http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .