Wasn't sure where to post this...you guys seem like the most knowledgeable about this stuff.

I want to buy a gas cylinder for an argon/co2 mix. I found a used one on craigslist that's 80 cu ft and he says he bought outright and has receipt (less than a year old).

What should I look for when buying a used tank that is owned (not rented)?

http://www.youtube.com/watch?v=ndGB-Ww47M4

Safest bet is to have him meet you at a welding shop where you were planning to have your cylinder filled. Take the cylinder in to be filled, if they fill it, pay the guy. If they refuse, return the cylinder to him and try again.

I agree about taking to to the welding house. What you need is a cylinder with a "slick neck" what that means is the collar around the top of the tank below the valve does not have any cast in names of a welding supply company. A personal bottle does not have this usually.

Thx COS, that's kind of what I have been reading. When welding supply places exchange your customer owned tanks - do they always replace it with a tank without a label/brand on it (assuming the one you had didn't have one either)?

Buying will save you beucoux bucks if your swapping tanks out frequently. I think we pay like $7 to swap out bottles that we own vs. $70-90 when you're renting.

No not always. I have a owner bottle on my mig welder that is not a slick neck. It's not an issue until you go to sell it or trade it in at another welding supply house. Just make sure you get a slick neck.