OT:co2 compatable O-Rings

[NiftyNev]

Anyone know a source (Australia?) for co2 compatable O-Rings. I have to replace them in a co2 valve on a cylinder that is used on an aquarium. The original seals seem to be very poor quality and fail quickly. Had a new spare cylinder and used the valve internals from that the first time the O-Rings failed but they didn't last very long. I need .375 X .500 O-Rings. The first set of seals blew apart during filling and the second set seem to have shrunk.

Nev

[NiftyNev]

More info on the valve. Spindle diameter is 0.382" and the body is 0.494". I was guessing on O-Ring size above so does anyone know correct dimensions for the O-Rings I would need.

Nev

[luthor]

According to the Parker O ring handbook you can use any of their O ring materials with co2. Looks like you need a 2-014.

[NiftyNev]

Wouldn't that be a 2-012. I have a box of o-rings here with numbers on it which I never knew what they meant. Looking at the Parker list the 2-012 is a 9.25mm with a cross section/width of 1.78. I have them and just tried one and they seem to fit. Am I correct in assuming the 012 which is in the kit I have is the correct one?

I may be confusing myself thinking o-ring sizes marked on the kit are actual size rather than the size of what they fit, or the other way round. I know nothing of o-ring sizing and applications.

Nev

[luthor]

Sorry Nev, yes it would be a 2-012. You should download the Parker O Ring handbook, it has all the information you would ever need about O Rings.

[NiftyNev]

Thank you. I have just been looking at the handbook. Very confusing at the moment, but I think I have learnt something already. Will give the 012 a try in the valve.

Nev

[NiftyNev]

Just thought of another question regarding lube. What, if anything should I use with the co2? Originals didn't have any lube that I could detect.

Nev

[luthor]

For use on an aquarium maybe Food Machinery Grease?

[form_change]

Try talking to Ludowici's They have branches in most capitals and are O ring specialists. If you took the fitting with you they could probably find the best ring for you. The original may have been the wrong one anyway (it can happen).

Michael

[NiftyNev]

Thanks for the replies. I had forgotten about Ludowici's. Went to them many years ago for some very hard to get seals for something and from what I remember they could source just about anything.

I think the 012 o-rings will work for now but have discovered that the problem may be the valve itself. When the valve is open, the spindle can be pushed down allowing the spindle and o-rings to pop out of the body.

Nev

[Black_Moons]

I don't think CO2 damages.. Much of anything, id more suspect high pressure (stronger material required?), stray burrs or something else mechanicaly damageing the O-ring, or maybe damage from freezeing when the CO2 bottle is rapidly discharged, or from heat if they fill it too rapidly

[NiftyNev]

Have installed the new o-rings and will get it refilled. In future I will replace the o-rings before every refill. Will only take five minutes to do and at the rate he uses the co2, I will only have to do this every few months.

Nev

[boslab]

I used some viton rings on a co2 bottle nose recently, the thing seems ok, prior to that i had some nitrile, they gave up ant the rig started leaking but i dont think it was the actual co2, it may have been damage from the insertion.
a problamatic set up with a bomb calorimeter in work always leaking was [third person passive!lol, its automatic] found to be the gauge stem being slightly eccentric to the thread so it was pinching the seal on one side more than the other, new stem of another gauge fixed that but it was a sod to unscrew from the other gauge [allen key inside the internal hex] i needed to use the gauge as it was a 40 bar oxy and thats a special, 16 bar is the run of the mill.
regards
mark

[RWO]

The paintball guys use a clear-translucent O ring on their CO2 bottles. I think they are silicone. Seems like I read that Buna-N absorbs CO2 and fails fairly quickly.

RWO