Minimum o-ring / o-rings / o ring / o rings set?

[Genesis]

Small quantities of O-rings are BIG mark-up items.

It is possible that some suppliers sell junk, but air-oil is a fairly significant industrial supplier and has been around for quite some time. I've used their products and haven't had trouble with them.

Do pay attention to the hardness ("duroimeter") ratings if there is a specific use that requires a harder compound .vs. a software one. Not really much of an issue for things like a yoke valve sealing O-ring, but it can become important for O-rings internal to regs and the like.

 

[The Chairman]

and use my O-Ring stretcher... he sure does complain! :tease:

 

[newdiverAZ]

you can buy 100 of all of the o-rings on that list for 60$. That would last a long time. in viton that is.

 

[newdiverAZ]

are all the buna o-rings 70-durometer?

 

[Genesis]

The site that I posted the link to has two different Buna-N hardnesses. There is NO WAY to tell them apart by looking at them - make sure you label your bins correctly!

For most uses 70 duro is fine; exceptions are typically, once again, on internal reg components.

There is no universal agreement on whether Viton is really a good idea with Nitrox or not. Viton is LESS shear-resistant than Buna-N for equivalent hardness, and while its harder to ignite Viton, its not impossible to do; further, if you DO get Viton lit you get some really ugly combustion products. Viton will last longer than Buna-N in a high-FO2 environment, but that's a relative thing too, since you probably will be changing them every year or so, right?

 

[equipto76]

Check out the O-Ring kits from www.reefscuba.com. I carry one in my save-a-dive kit and it's come in extremely handy several times. It's paid for itself in the dives that it's saved.

 

[FredT]

Scubaroo once bubbled...
011 - 3/8" LP port (buna/viton)
012 - 7/16" HP port (buna/viton)
013 - 1/2" LP port (viton)
Also throw in some lubricant - I've switched to only using Christolube on regulator o-rings - it's expensive but a little goes a looooong way.

If actually doing it according to the book:
3/8" LP port uses a 3-903
7/16" HP port uses a 3-904
1/2" LP port uses a 3-905

The cross section and size for those joints are defined by SAE, MS33656, and MS33657 to provide consistant sealing specs. They are NOT the same as the 2-0XX series! All are available in Viton (Parker compound V884-75)


FT

 

[jrudicel]

I am looking for anyone with specifics on some Orings I will be needing. I can just go to a dive shop and go through the hassle with them finding them, but would just rather buy my own through various companies we deal with at work like Mc Master Carr etc., that way I'll have spares anyway. I could try and measure them etc with calipers and such, but if anyone knows the specifics, it would save the time. I have PST 104's in doubles with the Halcyon 300bar manifold. I am due to bust them down, simple green and viz them, and want to replace the tank orings and the manifold orings while there. Anyone know the dash numbers, duro numbers, etc? Buna, Viton, etc? Obviously I am using them for pp filling as well. Thanks for anything you can give.

 

[froddo]

You can tell the hardness by rubbing the orings against hard surface. 90 will be harder than 70.

 

[GreenDiverDown]

Anyone know the answer to this?