Scubapro Mk10 - low intermediate pressure

[fmerkel]

Seems no one actually addresses this except to repeat the 'norm.
What's the harm in 4 shims? A few thousands more is going to make the reg fail/blow up/distort the spring/cough up the piston? What? Mechanically just doesn't seem to be that big a deal.

I have the same low IP on a reg. So far I just live with it. It functions fine.
(Note - I have not added the dreaded 4th shim. Awaiting clarification and DIY blessing, maybe forgiveness. )

 

[Couv]

Seems no one actually addresses this except to repeat the 'norm.
What's the harm in 4 shims? A few thousands more is going to make the reg fail/blow up/distort the spring/cough up the piston? What? Mechanically just doesn't seem to be that big a deal.

I have the same low IP on a reg. So far I just live with it. It functions fine.

Of course you are correct. Why not more shims or address the issue with thicker shims as some other manufactures do? In fact one of the manufactures of a clone of the venerable MK5 uses color coded shims to add and subtract upwards of 10 psi with one shim.

But again, the OP is trying to do it by "the ScubaPro Book" and cannot be faulted for that.

 

[Enraptured of the Deep]

But again, the OP is trying to do it by "the ScubaPro Book" and cannot be faulted for that.

Well, that's not exactly true ... I did use silicone grease rather than Christolube.

Maybe I should be really daring and add a fourth 0.015" shim???

 

[Angelo Farina]

Well, that's not exactly true ... I did use silicone grease rather than Christolube.

Maybe I should be really daring and add a fourth 0.015" shim???

On two of my very old MK5 I use a much thicker shim on one side of the spring. It comes from old Cressi regs, quite similar to Mk5, but with an external ring for tuning IP.
The thick shim compensates for the old spring which, after many years being compressed, had relaxed slightly.
There is no harm using thicker shims for restoring the proper spring load.
Definitely better than changing the spring...

 

[fmerkel]

Maybe I should be really daring and add a fourth 0.015" shim???

Go for it! Report back.
Now, I'll go put on hearing protection, eye protection, a mask (if I can find one ), and my asbestos suit. Then rummage around for some spare shims.

 

[Couv]

Maybe I should be really daring and add a fourth 0.015" shim???

Go for it! Report back.

Agree!

 

[halocline]

Well, that's not exactly true ... I did use silicone grease rather than Christolube.

Maybe I should be really daring and add a fourth 0.015" shim???

It's possible that using silicone grease is increasing the amount of IP swing from 3000 to 300 PSI. I don't know if it's likely, but it is possible, in the same way that using silicone could raise the overall IP.

 

[fmerkel]

So....ignoring the other (O2) issues, people are seeing silicone lube as superior to Christolube, as a......lubricant?
Can't say I've done a +/- comparison, so running on ignorance here.

 

[Couv]

So....ignoring the other (O2) issues, people are seeing silicone lube as superior to Christolube, as a......lubricant?
Can't say I've done a +/- comparison, so running on ignorance here.

As a lubricant, PTFE is better, but it's not as tenacious as Silicone. If you rebuild your regulators every year or two, PTFE is great. However, if it will be a few years in between service you'll find the silicone will outlast PTFE. The trouble with PTFE is the oil separates from the Teflon and leave behind "cookie dough."

Having said that, if you pack a sealed ambient chamber PTFE will last years.

I also find some of the older MK10s I've bought that were serviced with silicone grease to be better protected from corrosion than the ones that were lubricated with PTFE.

 

[Rusty Shackleford]

Is not 125 at the bottom edge of Scubapro specs?

I would tune the second to it and rock on.

My experience is I have seen IP increase after service but never the reverse.