exchanging cylinders? nitrogen for argon/co2?

[Pro-Painter]

Ive been looking throughout Craigslist for months now for a good used Argon/co2 tank to fill or exchange with no luck at all.
Today I found a large nitrogen tank posted for $100. To me, its looks like the same type of cylinder. However, they may be some differences that I'm unaware of. Will a welding supply shop fill or excahnge a nitrogen cylinder for argon/co2?

Thanks

 

[jeremy v]

If I remember correctly you can fill a nitrogen tank with CO2, but not the other way around, since nitrogen is stored in the tanks at much higher pressures than CO2 or argon/CO2, but the tank valve threads will be different and will require an adapter or else the valve will need to be changed out. CO2 uses a cga 320 connection for hooking a regulator to the tank and Nitrogen uses a cga 580 connection.

Another option you could ask about in your area that I have utilized a few times at my local welding shop is to trade in a tank like the one you are asking about towards an exchange for a CO2 tank. Many times the shop will do a straight across swap for you just to keep your business in the future when it comes time for refills.

Just make sure there are no company names stamped or embossed around the top ring of the tank as those are usually leased, rented, or deposit tanks and are not owned and able to be legally sold on the private market.

 

[m151]

More than likely the supply place will want nothing to do with that tank. If they do they are
going to charge you for testing and certification. I would go down there and show them the picture and see what they say before spending any money.

 

[keen]

all depends on your gas supplier.

honestly, though, bottles aren't -that- expensive.....and you can trade them up later. so buy the size you can afford now, and next time you fill it (or a few times from now) trade up a size.


if you find you can't really afford the initial investment, most shops will lease tanks as well. When you're looking at used tanks note that a lot of the stuff out there are -not- owner owned, they're often leased.

take the picture, go visit your local shop. see what he can work out to help you out. while you're there, ask him how to help you identify when the tank's last certification expires.

Some places won't fill trade swap or anything if they didn't sell the tank (TSC comes to mind...). Others will happily take a hit on a tank that needs recert in hopes of your future business. Just depends. If you don't get the answer you want, try another shop. You're going to have to visit them anyway.....

 

[acdc73]

depending on the age of the tank, it might be better to get a new one from the gas supplier.