Scubapro MK10 Seat

[Zung]

Are you referring to A242? ...

It's the A242 indeed. Sorry.

I would expect it would compare to the -II seat...

That's in line with what I found - Thanks.

Now signing off to a date with the stringrays in Southen Tenerife!

 

[Slamfire]

Tank pressure = 2300 psi

Reg 1 IP = 127 psi
Reg 2 IP = 120 psi

Looks like I need to put in some shims in these regulators.

 

[redacted]

I definitely would not mess with 127 psi as long as you are still looking at at least 120 @ 500psi. I usually try to set my 1sts in the 125 to 130 range. Even the 120 might work just fine. That is one where I might consider slipping a washer onto the seat retainer rather than going through the disassembly needed to add a washer.

 

[Slamfire]

Vance's book says 125psi to 145psi, but I think I can see the logic for aiming to a max of 130 psi. You'll have some extra padding before IP builds up to cause a 2nd stage to freeflow as the HP seat gets older. And a good well tuned balanced adjustable (eg G250) will be able to deliver plenty of performance at IPs of 125psi to 130psi -- there's really no need to take IP to 145psi.

 

[Couv]

..... Even the 120 might work just fine. That is one where I might consider slipping a washer onto the seat retainer rather than going through the disassembly needed to add a washer.

Alternatively, you can sand down the hp seat a little at a time until you've raised the IP to where you want it. Sand the side of the seat that interfaces with the inside of the seat retainer. Use a Sharpie Pen to make index marks on the retainer and seat so you can put it back in the same position. One other small detail that can change the ip is not screwing the seat retainer back to the exact same position, so index mark that relative to the body too. By the way, if you lube the seat, it'll come out of the retainer very easily.

c

 

[Couv]

Has anybody established the "value" of the Trident (A148) A242 seat? +, -I, -II?
I've just fitted one to a MK5 and the IP is kind of low-ish, in the 8 bar / 120 PSI range with a shim at the top and the bottom of the spring; but it's not broken-in yet.

I don't have any Trident seats, but a while back I mic'd a bunch of SP hp seats.
Here are the averages in inches.
(+ ).265; (-l) .275; (-ll) .305

Spring shim thickness ranged from .010 to .015

....again, I've got to get a life.

I think I'll go to Cozumel for about ten days.

c

 

[Slamfire]

I have trident seats but I don't have a mic. However, the Trident catalog states the height is 7.2mm = .283 inches.

 

[Slamfire]

Has anybody established the "value" of the Trident (A148) A242 seat? +, -I, -II?
I've just fitted one to a MK5 and the IP is kind of low-ish, in the 8 bar / 120 PSI range with a shim at the top and the bottom of the spring; but it's not broken-in yet.

Update on the quality of the Trident seats

About a month ago I got a new seat to service one of my Mk10's that was acting up weird (oring popping everytime I took a breath, not just on the initial pressurization). I replaced all dymanic orings and some static ones, cleaned everything with tsp, and vinegar, generously applied christolube and replace the hp seat with a brand new trident one. I reassembled everything. IP was at 130. I did not get a chance to take it out diving since I only use that one on deco dives.

Two weeks later I got my hands on some brand new 2-117 viton orings so I opened up the reg again and replaced that static turrent oring. I reassembled everything and now the 2nd stage is gently free flowing. I look at the IP and it sits steady at 200 psi. So I took out the HP seat and notice that the piston's knife edge has cut into it deeper than any other seat I've ever seen. Zero dives and a couple of testing pressurization sessions did this. Yes, I do make sure that I unscrew the reg body before starting to unscrew the HP seat retainer to avoid scoring the hp seat with the rotational motion. I replaced that new and failed trident seat with a new original SP seat and now the IP has been sitting steadily at 120 psi (2500 psi in tank) for the last 20 mins.

My conclusion is that this particular trident seat was just made up of inadequately soft material. So if you have to buy trident seats, my advice would be to buy more than one and be ready to replace them in the field. Also, be extra vigilant on the IP monitoring. So far I've gotten 1 failure out of three trials. Not very attractive odds.

 

[redacted]

Update on the quality of the Trident seats

About a month ago I got a new seat to service one of my Mk10's that was acting up weird (oring popping everytime I took a breath, not just on the initial pressurization). I replaced all dymanic orings and some static ones, cleaned everything with tsp, and vinegar, generously applied christolube and replace the hp seat with a brand new trident one. I reassembled everything. IP was at 130. I did not get a chance to take it out diving since I only use that one on deco dives.

Two weeks later I got my hands on some brand new 2-117 viton orings so I opened up the reg again and replaced that static turrent oring. I reassembled everything and now the 2nd stage is gently free flowing. I look at the IP and it sits steady at 200 psi. So I took out the HP seat and notice that the piston's knife edge has cut into it deeper than any other seat I've ever seen. Zero dives and a couple of testing pressurization sessions did this. Yes, I do make sure that I unscrew the reg body before starting to unscrew the HP seat retainer to avoid scoring the hp seat with the rotational motion. I replaced that new and failed trident seat with a new original SP seat and now the IP has been sitting steadily at 120 psi (2500 psi in tank) for the last 20 mins.

My conclusion is that this particular trident seat was just made up of inadequately soft material. So if you have to buy trident seats, my advice would be to buy more than one and be ready to replace them in the field. Also, be extra vigilant on the IP monitoring. So far I've gotten 1 failure out of three trials. Not very attractive odds.

Phil at Dive Sports reported a problem with the Trident HP seat when I was shopping for some. I have been running one along with the trident rivet style LP seat in a 2nd stage for some time now with no problem. Perhaps you just have to be prepared for some bad ones. Just be comforted by the fact that Scubapro refuses to sell OEM parts to us for our own good.

BTW. I never loosen the ambient chamber before I unscrew the HP seat retainer. They should only be in contact when under pressure. I have never had any problem.

 

[Rusty Shackleford]

I am trying to do this with a MK-10 Plus. That little hole is tiny. I think the 10+ uses the same seat as the MK-20/25.
I put the tiny hole over the face of the valve on my test bottle and opened it. Still no joy.

Any other advice?