So I was just informed during an equipment couse that viton Orings are no longer the choice for anything over 40% oxygen content. I beleive it was EPV or something like that is now the industry standard. Can anyone clarify this for me?
Viton Orings bad for 02?
- Thread starter Rings890
- Start date
Please register or login
Welcome to ScubaBoard, the world's largest scuba diving community. Registration is not required to read the forums, but we encourage you to join. Joining has its benefits and enables you to participate in the discussions.
Benefits of registering include
- Ability to post and comment on topics and discussions.
- A Free photo gallery to share your dive photos with the world.
- You can make this box go away
Jimmer
Contributor
EPDM is the "preffered" choice. Viton is resistant to combustion, but when it does, it lets out some serious fumes. I've never known of this actually happening to anyone. According to the Oxyhacker book, the aviation industry still uses Buna rings as standard for O2 service, and I had one manufacturer representative and very knowledgable tech diver, tell me to just use the company's standard rebuild with a good cleaning and Christo-lube, and there should be no issues with O2. The only thing he added was that the Buna CAN degrade a little faster, so the fix for that was to just be consistent about your annual service, and rebuild them before a problem presents. I think the general consensus is it comes down to the cleanliness of the parts and the lube being the major issues, and O-rings being the secondary issue.
As a side note, my instructor and I have been considering building a very small pressure pot and dropping in an Oring of each type and putting in O2, and checking them after a week to see if there is any noticeable breakdown of the material, simply for a curiosity issue, and not to be considered emperical proof.
As a side note, my instructor and I have been considering building a very small pressure pot and dropping in an Oring of each type and putting in O2, and checking them after a week to see if there is any noticeable breakdown of the material, simply for a curiosity issue, and not to be considered emperical proof.
- Messages
- 1,840
- Reaction score
- 22
- # of dives
- 1000 - 2499
Viton should be good for O2. I use EPDM. The Vitons that I have used in the past have shown some cracking at the annual inspection.
it depends on the application its being used..
some manufacturers prefer EPDM.. some of the charactics are better thab viton others are worse..
for example, epdm wrk at a lower temp than viton -40f compared to -10f, while viton has a higher working tempp.. 400f compared to 200f
viton has a wider range of chemical resistance than epdm when they do burn they release different chemicals.. viton releases flourine gas..
if epdm comes in contact with any natural oils, they swell severely..
Jimmer
Contributor
Agreed, I use Viton in all my regs when I overhaul them. But like you mentioned, Buna seems to be able to handle it, with the right use of O2 safe lube.
Gilldiver
Contributor
The only O-ring that sees a high O2 % over time is the tank neck o-ring. The rings in your reg see it for perhaps 4 hours a weekend (208 hours/year) for most divers. If you really are concerned, flush your reg on a bottle of air before any long term storage to reduce any high O2% in the hose and reg stages.
If you are diving more then 2 days a week, you should be increasing your maintance to account for this but anyway, you should still be much less then 500-1000 hours/year.
If you are diving more then 2 days a week, you should be increasing your maintance to account for this but anyway, you should still be much less then 500-1000 hours/year.
And that would only be for high O2 deco mixes.
I use viton on my tanks and manifiolds because they are readily available and fairly cheap. My regs get manufacturer specified o-rings. Not always sure the material, but the correct hardness, elasticity, etc. is key in this application and I don't want to muck with their performance since just about any available material is adequate even for O2 - given adequate cleaning and lube.
OP
I guess my big concern was my blending whip, and cylinders. I have all viton Orings and clean everything at the begining of each dive season just to be safe. (No need to blow the back of my garage out).
Since I have a large amount of viton on hand I will just keep using them. I allways use the manufactures Orings that come with my service kits.
Since I have a large amount of viton on hand I will just keep using them. I allways use the manufactures Orings that come with my service kits.
The biggest problem with viton is its extremely poor resistance to abrasion. In any dynamic application o-rings made from viton will wear out very quickly.
Similar threads
