# O2 regulator on CO2



## pfgrobler (Aug 21, 2004)

Is there any good reason not to use a O2 regulator on a CO2 cylinder ? I live is South Africa and CO2 regulators are +- $150 where as I can get O2 regulators for +- $60

As I understand it O2 is at higher pressure, and more corrosive than CO2 and as such the regulator should be fine ? The only reasoning I can see not to use a O2 regulator is that the CO2 cools quite rapidly if the regulator is opened fully and that might cause a problem if the regulator gets to cold.

Any one that is more knowledgeable know why I shouldn't

Phillip Grobler


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## brad (Jul 10, 2005)

My father in law has a tractor dealership and as such needs all kinds junk for welding and what not. When we were looking around for a co2 regulator he could spare, we came across a box full of brand new 02 regulators. I asked if that would do the same job. His response,`Don`t be dumb!` So, I don`t know why, but apparently there is a very good reason for it.

I know that didn`t help, but hey......


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## Laith (Sep 4, 2004)

In scuba diving, especially in tec diving where you sometimes breath high O2 content air, an O2 regulator is simply one that has been completely cleaned of all flammable lubricants, silicones and other materials. Because high percentage O2 is extremely flammable and explosive if it comes into contact with certain substances.

If you use an O2 regulator for anything but O2, you cannot use it for O2 again until it has been re cleaned completely and certified safe for O2 use.

Other than the above, I'm not sure why you couldn't use it. Maybe the fittings are different?


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## bharada (Apr 17, 2004)

Laith said:


> ...Other than the above, I'm not sure why you couldn't use it. Maybe the fittings are different?


In the US I think this is the case. Not sure if it applies internationally, though. Hopefully Rex will see this thread and chime in.


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## Bonsai_Swamp (Oct 14, 2004)

It should work fine. As I type this I'm sitting next to a converted two-stage medical O2 regulator quietly bubbling CO2 into a a 40 litre tank I'm "fiddling" with.

You'll need to convert the cylinder/regulator connector from O2 to CO2. I assume you use DIN fittings over there? A well-stocked welding shop should have the right sized fitting, but make sure they do before you buy the reg.

Beware of the small emergency kit oxygen regulators (the ones with the "litres per minute" flow control dials). Their inlet fitting is often smaller than a standard welding fitting, so they can be a pain to convert.



pfgrobler said:


> The only reasoning I can see not to use a O2 regulator is that the CO2 cools quite rapidly if the regulator is opened fully and that might cause a problem if the regulator gets to cold.


This might be a concern:

1) at high flow rates. Not a problem at our laughably low flow rates.
2) for setups which draw liquid CO2 directly from the the bottom of the cylinder. Around here you would either have to hunt long and hard to find a cylinder fitted with one of these valves, or tip your cylinder on its side during use. 0.5 brain = 0 problem.

As Laith pointed out, going from anything else to O2 is a different matter, but oil and aluminum won't spontaneously combust in the presence of high pressure CO2.


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## pfgrobler (Aug 21, 2004)

Thanks for the replay's O2 regulator it is then. The prices of things in the US just make me jellous. The adaptors to use them on CO2 are easily available.



Bonsai_Swamp said:


> 2) for setups which draw liquid CO2 directly from the the bottom of the cylinder. Around here you would either have to hunt long and hard to find a cylinder fitted with one of these valves, or tip your cylinder on its side during use. 0.5 brain = 0 problem.


That is actualy quite easy for me. I'm using a 2kg CO2 Fire extinguisher. They look exactly the same as other CO2 cyliders except that they are paited bright red and have push down valve. and probably the most important they have a syphon tube going right down to the bottom of the cylender. But I had this removed when I bought the cylinder.

Getting a normal CO2 cylinders is also a bit of a mission here as well and there pricing is not any better than for regulators. All the welding shops are get there gass from 3 major suppliers and they only rent out the clinders at +-$12/month or you can buy it from them for +- $300.

There are a few petshops that sell CO2 cylinders that they have imported you are again looking at +-$250 for a cylinder and $150 for a regulator.

So I would prefer to have gone the same route as you guys in the US but
$400 for CO2 reg + bottle vs $150 for O2 reg + fire extinguisher. I believe the australians havesimilar proplems in finding cheap sources of CO2.

I'd realy need a good reason for going for the pure CO2 route.

So unil some one gives a good reason not to, 02 regulator it whould be then.


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## gsg (Feb 17, 2005)

I am using too a fire extinguiser as my co2 tank, but there is no need to take out the inner tube they have. With the tube the co2 is taken from the bottom, in liquid form, and by opening the push valve it burst out and it becomes carbonic snow in contact with the air. But at the slow flow rates a regulator lets the gas out, it turns back to its gas form pretty easily and so they don't freeze the regulator.

I had problems here in Spain fitting my american Milwaukee regulator to the fire extinguiser, the connection threads were not the same, so i had to have a connector build at a welding shop.


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## Bert H (Mar 2, 2004)

You will need an adapter to go from the O2 to the CO2. CO2 has a CGA 320 fitting. Without that adapter you will not be able to hook up the regulator to the tank.


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