SPEC Boots for MK10 and MK15 primary regs

[James79]

Ok, if I'm understanding correctly, I could theoretically remove the back-case entirely, and the pressure gauge would still work, because all of the internal components are sealed, and pressure doesn't leak out into the plastic case? I'd assume I need to remove (or drill holes in) the rubbery protective-boot while I'm at it.

I suppose for maintenance, I could always flush it with a pressure washer, and then dry it out with compressed air after.

I think I get it, and it doesn't sound quite as bad as I first thought. Now to decide which IP gauge of mine I like less...

Yep, the little rubber plug on a normal pressure gauge is actually there as a blowout plug so a failed bourdan tube will pop the plug instead of blowing out the glass. The actual function of the gauge is independent of the housing.

 

[Couv]

Now to decide which IP gauge of mine I like less...

Home Depot has inexpensive gauges that are easily adapted in their low pressure compressor section.

 

[Kupu]

I just finished packing a MK10, using OEM SP boot. The regulator had been recently rebuilt so the process took about 15 minutes start to finish. A tube of Molykote was used, squeezing it into place made the process easy vs scooping out fingerfuls of grease from a tub.

IP was checked before packing, 138 psi on half empty tank. During the first few pressurizations after packing the initial IP reading was high, up to 155 but went back down after taking a single breath from second stage. After 3-4 times repressurizing the MK10, the initial high IP reading went away completely. Happy to say it is now steady at 138psi, as it was before packing.

By design, the SP boot has 1 small hole which allows the boot to compensate for change in ambient chamber volume that occurs when tank is turned on. A small worm of grease came out the during the first pressurization cycles, now nothing. The boot looks the same with tank turned on or off, no bulging or contracting..

All in all, the process was easy and successful. I am cleaning a MK5 with environmental kit and will try packing that in a day or two.

 

[SlugLife]

I drilled 2 holes in the back of an IP gauge, I think without hitting any of the internals. I'll just have to remember to hook it up, bring my dive-notepad, etc on my next dive.

 

[SlugLife]

I hate to delay, but the short-story is scheduling issues might mean it's about 2-weeks until I can do the underwater IP test. I might be able to squeeze it in before then, but we'll see. The short story is I'm about to go on vacation for a week, and who knows if I'll have the opportunity (or interest) in that kind of test while on vacation.

I do have some new HP seats, but haven't installed one yet. That doesn't take long, I just have to do it.

After week since my last-dive, the boot still is "sucked in", which suggests a decent seal. Given the other user mentioned the official SP Boot has a small hole, any leakage probably isn't a problem. I haven't seen any leakage other than the first time I pressurized it, and got a "splash" of grease flying out. If there's any water inside the chamber, it's probably fault of improperly packing grease.

 

[Couv]

Given the other user mentioned the official SP Boot has a small hole, any leakage probably isn't a problem.

Correct. As far as IP is concerned, water leaking into the ambient chamber is not a problem nor would it be detected by the submersible IP gauge. The concern is improper/incomplete packing of the ambient chamber PLUS a boot that makes a perfect seal. In this case the ambient pressure is NOT fully transmitted to the ambient chamber. This problem would cause a lowering of IP as the depth increases and would be detected by the IP gauge.

 

[SlugLife]

I just installed a new HP seat, and the pressure reads quite low now. I'm seeing 106 PSI with no creep, and cycled it around 25 times. Should I just give the seat a chance to settle in, or cycle it a few hundred times? Did I not seat it properly? Do I need to file a little material off the back? Dig into the grease and remove or add shims?

 

[James79]

I just installed a new HP seat, and the pressure reads quite low now. I'm seeing 106 PSI with no creep, and cycled it around 25 times. Should I just give the seat a chance to settle in, or cycle it a few hundred times? Did I not seat it properly? Do I need to file a little material off the back? Dig into the grease and remove or add shims?

I'm not a piston expert, and would defer to @rsingler , but I would suspect your new HP seat is a tad thicker than the original. A couple shims would probably do the trick (adding shims increases the preload on the spring, requiring higher IP to close. A thicker seat sits closer to the piston, requiring less spring compression and therefore lower IP to close).

Respectfully,

James

 

[Open Ocean Diver]

If you received three seats in your kit you need to use the shortest one. Assuming you reused the existing shims.

 

[SlugLife]

I'm not a piston expert, and would defer to @rsingler , but I would suspect your new HP seat is a tad thicker than the original. A couple shims would probably do the trick (adding shims increases the preload on the spring, requiring higher IP to close. A thicker seat sits closer to the piston, requiring less spring compression and therefore lower IP to close).

Respectfully,

James

That sounds about right. I don't have any shims and am about to leave on vacation for a week with the regulator. I might throw the old one back in temporarily. It was settling around 155 PSI after additional use, which is is high, but I think I'd be more comfortable with 155, than 106 PSI.

I guess I should order some shims in the meantime. Does it matter which shims I order?

If you received three seats in your kit you need to use the shortest one. Assuming you reused the existing shims.

I received some unbranded seats from fleabay, that are all the same size.

I seem to remember there being a thin shim on each end of the spring on this regulator, but I have 4 MK10s and get them mixed up sometimes.