Welding Tips and Tricks

Hi all,

I have been looking at picking up a spare tank (for c25) for my mig welding in case I run out. Looking locally at used tanks I see helium and/or oxygen tanks pop up occasionally. With my local supplier Praaxair, I normally bring in my tank and they swap it. The original one I have is a used one I got from them. I am wondering what used tank I can buy and then have them swap for a c25 tank and does the date code on these used tanks actually matter if they swap?

cloves wrote:Hi all,

I have been looking at picking up a spare tank (for c25) for my mig welding in case I run out. Looking locally at used tanks I see helium and/or oxygen tanks pop up occasionally. With my local supplier Praaxair, I normally bring in my tank and they swap it. The original one I have is a used one I got from them. I am wondering what used tank I can buy and then have them swap for a c25 tank and does the date code on these used tanks actually matter if they swap?

Even within the same company, local operating practices can vary greatly. What my Praxair does for me, yours may not do for you, and what yours does for you, mine may not do for me. Hence we are not the people you should be asking. My point is you should not take a chance and simply call them and ask them.

That being said, my LWS will accept any Ar/C25/He tank and can exchange for which ever of the 3 gases that you want, you simply pay for the gas contents so long as the tank has a currently valid hydro-test. You may be able to get away with bringing in a He tank and exchange it for an C25 because they will likely have the same cga580 valve, but the oxygen your guess is as good as mine, until you call them and ask.

Thanks Oscar I get what you are saying about a variety based on region and supplier. My local supply had already closed by the time I saw the tank on sale locally on craigs. I'll have to also about the hydro date next week if they are open.

This might get long winded but here goes. I pick up dry ice for the company I work for once a week and I get it at my LWS. I have managed to build a really good rapport with the guys there. Got to talking with them when I saw a CL ad for a torch set but it said the tanks would need to be hydro tested. The set was priced right but I thought the hydro would be expensive. When I asked my guy, found out a test was like $15, but they didn't do them on site. He said they would just exchange it anyways. So I asked, a tank is a tank is a tank? He said yep, so if I bring an empty oxy I can trade straight across for the same tank size of whatever gas I want, just pay the gas price. I have managed to get 7 tanks, various gasses, some empty some still containing gas, from CL for some really good prices. Now there is another supply house across town that will only exchange an argon bottle for another argon. So in closing, talk to your supply house, get chummy with em, and see if they will work with you. Good luck.

Thanks for sharing that varekai.

Word of caution from some people I respect that taught me.

Be aware that if you buy a used tank that is stamped on the neck by a company, your LOCAL WS may not deem it a valid exchange tank even if you bought it on CL. The stamp means that the tank is owned by a company and it appears to the LWS as stolen. Just a warning. If buying on craigslist, look at the certs/cal and look for stamps on the neck. You don't want to see any.

Good hunting.

bap_ wrote:Word of caution from some people I respect that taught me.

Be aware that if you buy a used tank that is stamped on the neck by a company, your LOCAL WS may not deem it a valid exchange tank even if you bought it on CL. The stamp means that the tank is owned by a company and it appears to the LWS as stolen. Just a warning. If buying on craigslist, look at the certs/cal and look for stamps on the neck. You don't want to see any.

Good hunting.

Very true. Some places have no tolerances and will not accept them. Here locally, if I buy a tank from Praxair or Airgas, they are stamped as such, but they still sell them that way, and either one will accept any tank that is currently valid on hydro. Same goes my LWS Tim's. If out of hydro, they will still exchange but charge the test fee for that tank to get tested off-site. And then there are some places that won't budge no matter what! lol So call your LWS, is what we're all saying.

Definitely call around, some places won't fill or exchange bottles over 125CF, other places will let you pay the difference and trade up to a larger size if you decide you want a bigger bottle. Others will only do that up to a certain size etc.

Case in point last summer I bought a 125CF 75/25 for $280 all said and done after tax and about 35-40 to swap it out for a full one later pretty decent price considering other local places were quoting closer to 400 for that size, and 60-70 to exchange it. Not took long ago I was looking into getting a torch and went down there to price bottles, 430 for a 244 CF oxygen bottle, 240 for a 60CF acetylene, next size up was $315, bit more than I expected so I decided to think on it.

Recently I leased a 330CF bottle of spray gas from a place a little further away, and while I was there found out it would only be 29 dollars to exchange my 125 CF bottle of 75/25. Asked how much to trade up to a 244, was told that 125CF was the largest you could trade up to or exchange. I still wanted to be loyal to the shop closer to me when I could though so I called them, the price had been raised to 60$ before tax... suddenly quite a bit harder to justify.

You might be asking what they has to do with anything, well say I'd had a little more cash and decided to buy the 244CF instead of 125CF from the local place or had a smaller cylinder and traded up to a 244CF tank there. When they raised their gas prices I would've been stuck either having to pay upwards of 70 dollars or more per exchange or have a completely useless tank. Even as it if I ever end up doing enough short circuit mig to need to regularly exchange my 75/25 tank, I'm probably better off selling it and leasing a larger tank than paying twice as much to swap it closer or making a 60 mile one way trip on a regular basis.

Some places have a rent by the month price. If you rent a tank and return it before the 30 days then you only pay for the gas, refill cost. The monthly rental price might only be $10 or less. So if your in or near by often then you can regularly change your bottle, even before it’s empty, only paying the refill / gas price. Worst case you pay a little rental fee. Do that for 6 months and see if the bigger size tank is worth the cost of buying it. Plus after 6 months you’ll have a good idea how good a place it is to work with, and they might give you a much better price after they know you 6 months.