Apeks 1st stage diaphragm clamp leaks

[taimen]

My recent experience is that one of the more common failure points in Apeks 1st stages (DST, DS4, US4) is that leaks appear between the 1st stage body and diaphragm clamp (AP1473). I have experienced this with several regulators approaching their recommended 2 year service interval. The leaking seal is apparently the diaphram seating, due to detoriation of the diaphragm or loosening of the metal to metal tightened joint of this diaphragm clamp.
How common is this? Do you have any recommendations how to avoid this? Do you use a specific torque for tightening the diaphragm clam when servicing?

 

[shurite7]

There is a torque specification for the diaphragm clamp. I don’t have my schematics in front of me so unable to give the specific answer. I haven’t come across your problem except once and it was because the owner didn’t rinse or spend any time maintaining his reg.

 

[grf88]

Have you checked the IP for drift. I have seen that problem on a similar reg when the high pressure seat was not sealing correctly.

 

[happy-diver]

All I can say is when I get them from the factory and I disassemble them to check them, the torque is TAF

Tight As F***

The screws need dressing smooth

 

[grf88]

I think they are tightened until you get metal to metal contact.

 

[Sevenrider860]

There is no torque specification for the diaphragm clamp. For the DS4/US4/DST the diaphragm clamp is to be "tightened until you get metal to metal contact".

I have not seen the leaking problems you are describing in my personal Apeks regulators (4 DST, 2 DS4) nor had them reported by customers that bring theirs in for service. While the old diaphragms take a "set" and are no longer flat, I have never seen deterioration on the edges where the the clamp makes contact.

 

[happy-diver]

People that shouldn't be fiddling with regs fiddling with regs
People reusing old diaphragm upside down
People not tightening enough
New diaphragm
?

How do you spell diafram

 

[rsingler]

While the old diaphragms take a "set" and are no longer flat...

This concerns me a little, with our new style gray thin diaphragms. With metal-to-metal contact, (unlike with a torque setting) everything depends upon perfect machining and consistent diaphragm thickness from the (secondary) manufacturer. At least with a torque setting, you can confirm the sqeeze on the diaphragm. With metal-to-metal, you're depending upon a hidden manufacturer-determined gap, and a diaphragm that precisely matches specification.

@taimen , can you describe the bubbles? Are they huge, like a loose diaphragm? Can you hear the reg hiss?
You mentioned loosening of the metal-to-metal contact specification. Could you feel that on attempted retightening of your own reg? Or is this one of the theoretical possible contributors?

 

[Centrals]

Never have torque setting for the diaphragm clamp or the end cap(no mentioned in my 2002 service manual)
Happened occasionally.

Is the environmental seal bulging out also?

Time to service anyway.

 

[rsingler]

So now we have two folks with Apeks diaphragm leaks - @Centrals and @taimen !

Makes me want to do a more compete bubble check on my JJ-CCR. Hmmm.
And @taimen 's comment that it happens around the two-year mark isn't reassuring when I'm used to letting a first stage with stable IP and crisp lockup go three years.