Mk11 Split-off from Regulator Geeks, Part II

[Couv]

I'm getting lost here, but if you have a MK11 and want to upgrade it to a MK17 the kit is slightly different. The MK17 has a thinner diaphragm, 2 washers (rings) instead of 1, and of course the environmental seal.

MK17 sealed chamber diaphragm 10117119
MK17 main diaphragm 10117107
MK17 diaphragm ring 10705110

That is just the kit parts, the environmental cap/transmitter/diaphragm retainer etc also need to be installed.

I'm all for an environmentally sealed first stage, but if I do not have one I don't sweat it if I'm continuously diving. A dunk and rinse every day followed by a long soak after a trip is all that is needed. Salt crystals need time to form and generally speaking will not as long as the parts never dry out.

 

[Geo7]

It's an interesting idea if you really need sealing, but some of us prefer unsealed regs when it is not needed. I grew up diving in cold water quarries in Germany, and few people bothered sealing their Poseidons back then. So diaphragm regs are already very freeze resistant, even if Apeks and Scubapro do not certify their unsealed 1sts for less than 10°C, they do fine.

With regards to sand and salt, that might be a slight advantage, but I think corrosion would need more time to cause corrosion in a brass Mk11. Loss of chrome would not affect any sealing area in this kind of reg and require no restoration to make it functional again (unlike a coroded piston reg). And a Mk11T is most likely completely trouble free since not even sand can scratch any important surface (again, unlike a piston reg). Finally, sealing it would reduce one of its strenghts: the light weight. So: interesting idea, but probably not necessary...

 

[-JD-]

I'm beginning to think that really the only "risk" is more frequent replacement of the spring in the ambient chamber ... Is that correct?

 

[Couv]

There are 50 year old (+) unsealed regulators that have never had the spring replaced. Think Conshelf...

 

[-JD-]

Is there any real issue with Nitrox (<40%) and the SP MK11Ts?

Atomic says they uses Monel for Nitrox compatibility on their Ti regs, but I can't find any SP info on the MK11Ts (or much of any info that they exist at all for that matter.)

 

[lexvil]

I'm beginning to think that really the only "risk" is more frequent replacement of the spring in the ambient chamber ... Is that correct?

Normally it probably would, every third or fourth lifetime

 

[lexvil]

Is there any real issue with Nitrox (<40%) and the SP MK11Ts?

Atomic says they uses Monel for Nitrox compatibility on their Ti regs, but I can't find any SP info on the MK11Ts (or much of any info that they exist at all for that matter.)

I doubt it.

 

[Geo7]

Actually, I would not worry about that steel spring since the innards will dry eventually so that steel spring should be fine. An inexperdly sealed piston reg with air pockets in the lube that keeps salt for months on the spring is another matter, and Wookie reported that he had rusty springs. Those springs are fairly cheap anyway, in such regs the spring is the lesst of worries (see rsinglers post on restoration of piston regs).

Rsingler showed pictures of unsealed dipahragm regs that had sand and silt near the diaphragm and had corroded the base plate and retaining ring there (after months of neglect I assume). That retaining ring is probably cheaper to replace than the price of a christolube filling for an Atomic, and even if not replaced should not really have an impact on function.

When I am doing 3 week trips where I can't rinse gear, I just don't let my gear dry ever. Then at home I rinse and soak religiously for days (pressurized if need be). The result is no corrosion on my regs (but I also lube all threads well).

IMHO, the damage to regs is done by not rinsing and storing them like that for months (and especially getting saltwater inside the HPor LP area of a reg and ignoring it).

 

[lexvil]

one can always look at insane alternatives, like the MK 21 and silicone

 

[Geo7]

Is there any real issue with Nitrox (<40%) and the SP MK11Ts?

Atomic says they uses Monel for Nitrox compatibility on their Ti regs, but I can't find any SP info on the MK11Ts (or much of any info that they exist at all for that matter.)

Some early titanium regs caught fire, and Atomic wanting to be the best and offer their flagship titanium reg went to Monel to make their reg pass the fire tests. Apparently they keep the fire from spreading, but I think/guess the reg would still need expensive service and would not be diveable after a fire. Not sure if a Mk11T would catch fire. Prevention is paramount, and most regs taching fire would be trouble. Personally I'd keep nitrox below 30% in any titanium reg, and keep the reg clean.