JoeM

Hi! I'm dealing with this situation right now myself. I have an 80cuft tank with C25, and want to change the contents to 100% argon. My supplier said that it would be fine for them to go from argon to C25, because there's argon in both cases, but going from C25 to argon requires a "green clean" process (whatever that is) because any residual CO2 will contaminate the gas if you are wanting to use it for TIG welding. He said they send the tanks out for that, and it takes a week or two for turnaround, and there's some additional cost. I'm trying to find out what this process is, whether it's really just purging the tank and evacuating it to a reasonably high vacuum to remove as much of the previous gas as possible, or if there's more to it than that. Heck, I can probably do that here at home; I have a small vacuum pump which can pull 25in of vacuum, and afterwards I can transfer a bit of argon from my other tank into it. Do this a couple of times, and I'm thinking that there will be essentially zero CO2 left inside. However, in the interest of safety and a quality result, it's better to let them do it. It's just a few bucks, and I'd hate XXXX XXXX to end up with a tank of bad gas that just causes a ton of grief when trying to get a good weld. -- Joe M.