Mk25 Question

[Tekkie]

Hi,
I just got a Mk25 (which I am very happy about) and I was wondering if the piston can be dry sealed for cold water use?
Is there a kit I can get to seal it?

Thankz....

 

[oxyhacker]

SP traditionally used a grease to enviromentally seal their piston regs - you'd fill the ambient chamber with silicone grease. Messy but very effective, and it also gave some protection from from corrosion.

With the Mk20/25 SP started looking for a cleaner method doing so and came up with the TIB (Thermal insulating bushing) later to become the TIS (thermal insulating system); various combinations of plastic bushings and sleeves that were supposed give added insulation. Many serious cold water divers felt they were less effective than the old grease, and started packing their Mk20/25s with the grease, and SP eventually said it was all right to do so but only for the actual cold water dives - it should be cleaned out afterwards and not left in year round as most of us did with the MK5s and 10s.

So the answer is yes there is, but your reg isn't supposed to need it and its a lot of hassle since it means an extra trip or two to the shop every year (unless you can do it yourself. But how cold are you really diving? I'd check around and find out what other divers diving the same sort of water as you are with the same reg before I started pumping in the grease. If you want to seal it for maintenance rather than cold water reasons, don't bother - just be scrupulous about rinsing the reg and you'll be fine.

Oh and grease packing is not a good idea with high FO2s thought I haven't heard of anyone having trouble at recreational nitrox levels.

Tekkie once bubbled...
Hi,
I just got a Mk25 (which I am very happy about) and I was wondering if the piston can be dry sealed for cold water use?
Is there a kit I can get to seal it?

Thankz....

 

[RSdiver]

It sounds like you are looking for an environmental seal kit. SCUBAPRO does make them for the Mk16 and 18 but those are balanced diaphragm models not piston designed like your Mk25.