ScubaPro G-500

[Scubagaskets]

No. I have them in EPDM 70 Sh , FKM viton for nitrox Sh 75 and Green Viton for 100%oxygen Sh 70. You can use those o-rings for pressures up to 100 bar. over that point you will need to use the stiff ones (Sh90).
What is the pressure level at the point of use?

 

[rsingler]

No. I have them in EPDM 70 Sh , FKM viton for nitrox Sh 75 and Green Viton for 100%oxygen Sh 70. You can use those o-rings for pressures up to 100 bar. over that point you will need to use the stiff ones (Sh90).
What is the pressure level at the point of use?

Scubapro specifies EPDM Sh85 for this o-ring. In my opinion, the failure the OP described is exactly the sort of early failure one might expect when someone substitutes a Sh70 o-ring for the HP shaft seal in a piston regulator that may see 3442 psi.
From looking at your catalog, you indicate that "an 010" can be used for the Scubapro .136 o-ring, without specifying Shore. Just as the OP indicated that he wanted to buy "a bag", I suspect that many DIY'ers have used too soft an o-ring, placing themselves at risk for an early failure.
What Shore and material do you use for the .136 equivalent in your Mk25 kit? And how do you justify substituting either material or Shore from the OEM, since you do not supply EPDM Duro 85 2-010 o-rings?

 

[Scubagaskets]

Scubapro specifies EPDM Sh85 for this o-ring. In my opinion, the failure the OP described is exactly the sort of early failure one might expect when someone substitutes a Sh70 o-ring for the HP shaft seal in a piston regulator that may see 3442 psi.
From looking at your catalog, you indicate that "an 010" can be used for the Scubapro .136 o-ring, without specifying Shore. Just as the OP indicated that he wanted to buy "a bag", I suspect that many DIY'ers have used too soft an o-ring, placing themselves at risk for an early failure.
What Shore and material do you use for the .136 equivalent in your Mk25 kit? And how do you justify substituting either material or Shore from the OEM, since you do not supply EPDM Duro 85 2-010 o-rings?

The identification process of all the o-rings and material was made by the use of the original scubapro service kit and in close cooperation with my consultant company in Holland.
In the kit of Mk2 plus there was no 01-050-136 oring but the 01-050-132 oring that was identified to be made of EPDM material size 010 Sh 70. You can see in the product description all the o-ring sizes -Sh and material of my O-ring service for scubapro MK2 Plus Scubapro MK2 Plus O-ring Service kit - Premium O-rings Provider for Scuba Diving
For the 01-050-136 you can use Sh 90 NBR if we are talking about normal air dives
Hope this answer your question
regards
Nicolas

 

[Couv]

Hope this answer your question

I hope this:

Scubapro specifies EPDM Sh85 for this o-ring. In my opinion, the failure the OP described is exactly the sort of early failure one might expect when someone substitutes a Sh70 o-ring for the HP shaft seal in a piston regulator that may see 3442 psi.
From looking at your catalog, you indicate that "an 010" can be used for the Scubapro .136 o-ring, without specifying Shore. Just as the OP indicated that he wanted to buy "a bag", I suspect that many DIY'ers have used too soft an o-ring, placing themselves at risk for an early failure.
What Shore and material do you use for the .136 equivalent in your Mk25 kit? And how do you justify substituting either material or Shore from the OEM, since you do not supply EPDM Duro 85 2-010 o-rings?

and this: Scubapro O-ring Sizes
answers your question.

 

[Rusty Shackleford]

No. I have them in EPDM 70 Sh , FKM viton for nitrox Sh 75 and Green Viton for 100%oxygen Sh 70. You can use those o-rings for pressures up to 100 bar. over that point you will need to use the stiff ones (Sh90).
What is the pressure level at the point of use?

The pressure level at that point (the HP O-ring) would be whatever ambient tank pressure is. Up to 4000psi for arguments sake. I don't have a way to convert that to BAR at this time. I would assume well north of 200 BAR

 

[Rusty Shackleford]

Internet calculator says 4000psi = 275 BAR.

 

[Rusty Shackleford]

And Couv, being a regional Scubapro center, I suspect it was the correct O-Ring, I blame the failure on the backing spacer being turned upside-down You can actually see the mold marks imprinted on the O-Ring where it deformed. I even saved it.

Of course, being who they were, I also am surprised the tech would make such a rookie mistake.

 

[Rusty Shackleford]

Actually, I think you are onto something.

That bastard squishes awfully easy! I just grabbed it! I bet it's the wrong ring on top of everything.

It feels SOFT!

Looks like we are up to two mistakes!

 

[Couv]

Actually, I think you are onto something.

I'll accept any credit you want to assign, but I was speaking generally about the seals Scuba Gaskets keeps linking to. I am happy to see a vendor willing to supply any parts related to our hobby, but the first order of business is to get them correct.

Good luck on your project Rusty, it's pretty easy to compare o-ring hardness by squeezing a known seal between your fingers.

 

[Rusty Shackleford]

Happy to report all is well. Made three 'eclipse' dives today at Summersville Lake (WV). Regs did great, just a very slight freeflow when the knob is all the way out. A quarter twist and it stops.

I still think I prefer it's contemporary the G-250HP (actually, not called an HP because of the brass air barrel but still has the balance chamber.)

I took the cursed G-500/MK-20 to 74 feet solo (with my 30cu/ft pony MK-2/190 for a back-up)

Thanks for the help, I am going to order those Viton 90 duro O-Rings for spares.