Question O-Rings Vs Quad Rings for Piston Seal on MK10 Clone

[Kupu]

A sealed piston first stage sould eliminate the potential for water intrusion into the ring groove.

I agree with you on the 010. I'm contemplating changing that one to a quad as well.

Are quad rings available that are designed to handle gas at 3000-4000 PSI without backup?

 

[rsingler]

Maybe it's time to redo my sealed Mk10 with quad o-rings!

 

[halocline]

I have similar thoughts as Kupu; IMO there is not currently any problem with the piston head seal in MK10s. The x ring might work, but I don't see that it's solving any sort of problem. What I would be interested in is something that reduces extrusion and friction at the HP piston seal. So if there's a high durometer 010 x ring to try in that spot, I'd be happy to do so. What I would do is take a pair of MK10s (I have several including a sealed pair) rebuild one with a standard EPDM duro 90 o-ring, and the other with an x ring and measure IP rise at high supply pressures. If the x ring-equipped MK10 rises less at 3000+ psi supply, I'd say that would be successful.

There's a place called ace seals that offers a 90 duro polyurethane 010; I guess that would be the one to try. I wonder about the lifespan of these o-rings. I'd probably want to dive one in OW for a while before relying on it in a cave.

It's a very interesting idea and thanks to the OP for bringing it up.

 

[rsingler]

Well, quad orings in 2-010 size AND 90 durometer are hard to find! But Precision Associates in Minneapolis are willing to do a run of 150 in Buna-N for $1.15 apiece after shipping, with a 10-week wait for the run. Marcorubber had an MOQ of 1000 for $730.
How many folks want 10 orings to play with, to defray costs?

I'm going to try it in a Mk5, a Mk10, and in my DGX XTRA. Even though the XTRA is an unsealed piston , it has that second oring next to the ambient chamber that may keep the HP o-ring dry. Might even try it in an Atomic. This could be fun if I don't have to shell out all $175 myself.

@halocline , I've worked with a Ace Seals on some custom stuff for my JJ-CCR. Good folks not too far from me. I'm waiting on a quote from them too! Maybe they'll be less.

 

[lexvil]

I’ll take 10 or 20 if it helps.

 

[JP_SCUBA]

I'll take 15 of those. Just let me know....

 

[JP_SCUBA]

My primary reason for asking here if anyone had used a quad ring (or X-ring) in place of the o-ring for the piston seal on a SP MK5 or MK10 was because I had run out of that size o-ring and since it was one of my spare regs I thought I'd give it a try. I never thought it would draw this much interest. But that's a good thing.

 

[Kupu]

If the -017 quad ring installed by @JP_SCUBA has passed a pool test, I take a chance and chip in for 15 pieces of the special order 2-010.

 

[rsingler]

Okay. I just put in the order for a run of nitrile 2-010 sized quad orings in 90 Duro. See y'all in 10 weeks!

 

[JP_SCUBA]

If the -017 quad ring installed by @JP_SCUBA has passed a pool test, I take a chance and chip in for 15 pieces of the special order 2-010.

Kupu... Yes, all went well in the pool. Only have 10 ft. depth but no issues (not that I expected any). I made 3 separate dives and sat on the bottom for 20 min. each time. All good. Now to replace the HP -010 piston shaft O-ring with a Buna 70 Quad/X-ring and do it again. Stay tuned ....