Making a Reg O2 Clean

[cave_diver]

Almost every regulator out there can be “upgraded” from Nitrox to O2-clean as long as there are Viton o-rings available. What you need is a clean work area (dust does not go well with pure O2), special O2 approved grease, and Viton O-rings. It also helps when you know how to service a regulator (i.e. you are trained to do it). You simply take your first and second stage apart, clean all part with an Ultrasonic cleaning machine, replace all existing O-rings with Viton O-rings, and lubricate all O-rings with O2-approved grease. You should, of course, replace the filter as well and check the piston (if it is a piston-style regulator) and any other parts for wear and tear. Re-set the intermediate pressure to manufacturers specifications and you are done. It usually costs around $50 to O-2 clean a first and second stage and it takes 30 – 45 minutes, depending on condition.

The reason why manufacturers often limit their O-2 to 40 percent is the potential liability exposure. Insurance companies don’t like exotic gases, and either increase liability insurance premiums dramatically or exclude coverage for anything other than air or up to 40 percent Nitrox altogether.

Accidents did happen while handling pure O-2, and people did die in the process. However, O-2 is invaluable as a deco-gas. However, you need not only special training in regulator maintenance; you need also special training in using higher mixtures of Nitrox (technical Nitrox).

 

[Packhorse]

From what I understand Viton Orings are not a necessity. Buna works just as well. Just make sure they are new and have no silicon lube.

 

[Hoosier]

From what I understand Viton Orings are not a necessity. Buna works just as well. .

You might be confused Buna-N with EPDM. I have never heard that Buna-N is OK for O2 cleaned reg......


For 50% bottle, the brand new reg. will be fine.

 

[Packhorse]

Cant find where I read it now so cant verify. It may have been in oxyhackers. And then it may have only referred to <40% mix. And as you say I may be confused.

 

[DRsharky]

There is no simple answer for your question, there are so many types of regulators and each requires a different procedure.

 

[Thalassamania]

"Approved for 40%" is a joke because 40% or less does not require any special stuff, no cleaning, no parts, no special lube. Oxygen clean is another story, if you really need oxygen clean, have someone who knows how do it.

 

[pescador775]

For the umpteenth time, the best materials for a regulator based on mechanical properties are nitrile and polyurethane. WRT oxygen, the Parker handbook rates nitrile a "2" and urethane a "1". Scale is 1-4 with 1 being highest for oxygen compatibility. According to this information below Aqualung and Apeks have "banned" viton:

http://www.scubaboard.com/forums/regulators/230412-why-has-aqualung-banned-viton-o-rings.html

Parker handbook:
http://www.gulfcoastseal.com/downloads/ord5700.pdf

Preparing the nitrile O ring (according to me): wash in ENSOLV, smear with Christolube (and don't be shy about it).

Follow your regulator manufacturer's recommendations.

Pesky

 

[Packhorse]

Nitrile being Buna N yes?

So you use Nitrile in O2 regs?

My understanding is that they will oxidise quicker than normal but will still last longer than a yearly/2 yearly service.

 

[divengolf]

I understand that some (or all) Dive Rite regs are O2 compatible (>40%) out of the box. Are there any other regs that are sold as O2 compatible. Virtually all the specs I have looked at, other than Dive Rite, are only up to 40% O2 which doesn't buy much.

 

[pescador775]

Packhorse, I went through a kind of evolution on this. Originally, I was like everybody else, "mygawd, I need viton". This, coincidentally, is somewhat similar to what is happening in the dive industry. They need to satisfy the lawyers and engineers without creating problems for the end users (customers). The lawyers don't like anything which can combust with production of phosgene gas (viton) or slowly degrade in oxygen and the engineers don't like something which will be durable in oxygen but whose lousy mechanical properties contribute to degradation of performance of the regulator or related equipment. These are in conflict. Viton and EPDM are just not as reliable in air or nitrox dynamic systems as nitrile and urethane. Same problems and trade offs with seat materials. Previously, nylon was a no-no for oxygen and now it is looking not so bad after some bad combustion vibes from oxygen approved polymeric fluorocarbons which were being touted for this purpose. (These are teflon type materials but with higher density or hardness). They work well mechanically but there is this combustion thing). Bottom line, until we hear from the manufacturers, who don't seem to know much and are constantly changing their priorities, it is up to us to weigh these things.

When O2 preparing a simple diaphragm reg like the Conshelf, I disassembled the nozzle (high pressure block), rinsed it and its parts in ENSOLV and inserted a viton O ring in the balance chamber. I used Christolube generously. That's all I did and it works fine with oxygen. If I had it to do again, I would use viton if I had the stuff or nitrile if not, and would not lose any sleep. The thing is, a regulator is not exposed to HP gas for extended periods. Even considering a heavily used regulator the nitrile O ring should last at least two years as you mentioned.

Now, piston regulators are more touchy than a diaphragm mechanism. They live and die by their O rings. I would not replace the original O rings design and materials for anything, even oxygen. After cleaning with ENSOLV, I use the original parts type and grease up with Christo.

As to seat materials, I don't much care what they are. I use whatever is in the regulator or valve originally. As to the PCTFE and related compounds, they are excellent materials for seats and seals. I'm not concerned about gas fumes. If there is a regulator or tank fire that is not the time to be worrying about a puff of toxic gas. Run!