Is Scubapro Mk2+ a cold water reg? I tried to search more info about TIS but could not find much details. How does TIS work? It seems that it's a coating on the spring but will the coating last? For those who have dove it in cold water, how cold do you think it could handle?
Is SP Mk2+ a cold water 1st stage
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halocline
Contributor
It has a good reputation for cold water use. The TIS is basically a coating on the spring and a couple of plastic bushings in the ambient chamber that are designed to help keep the piston from freezing. The lower flow of this reg helps.
It is not a fully sealed reg, though. Most ice divers will want to use a reg that never allows water in the ambient chamber.
It is not a fully sealed reg, though. Most ice divers will want to use a reg that never allows water in the ambient chamber.
hudson
Contributor
I've "abused" mine in 42F in similar air temperatures (without any consideration to avoid excessive cooling..that is breathed them on the surface, breathed them while inflating etc) and they work fine. With TIS they should be good for even ice diving based on past reports here.
It's a piston reg and diaphram regs have a better track record in cold water applications. The SP MK 2 is a "low end" regulator by any means.
Several divers I used to hang with used them for ice diving with no problems.
The TIS system in the Mk 2 uses a bushing to provide thermal insulation between the main reg body and the spring. The teflon coating on the spring also prevents any ice that may form from sticking.
In the Mk 2, there is very little air flow in and out of the compression chamber, so no special effort is needed there, the cooling occurs in the reg body near the orifice, so the TIS kit works to insulate that end of the piston and ambient chamber.
The TIS system in the Mk 2 uses a bushing to provide thermal insulation between the main reg body and the spring. The teflon coating on the spring also prevents any ice that may form from sticking.
In the Mk 2, there is very little air flow in and out of the compression chamber, so no special effort is needed there, the cooling occurs in the reg body near the orifice, so the TIS kit works to insulate that end of the piston and ambient chamber.
halocline
Contributor
SP used to have an anti-freeze system called SPEC, (silicone protected environmental chamber, I'm guessing) which was basically packing the ambient chamber with silicone grease, and using a rubber band-sort-of-thing to keep the grease from leaking out. It was reputed to have worked very well, and if I could find a couple of MK10 SPEC boots, I'd pack my MK10s just to give it a try. I don't know if they ever used it on the MK2, but they did on the MK5, using really small holes rather than the boot to keep the grease in place, on the MK10, and if I remember, early MK15. After that they went to the TIS for the MK20 and 25.
All of this is somewhat academic to me because I never dive in cold water.
All of this is somewhat academic to me because I never dive in cold water.
No argument with any of what you said. I use plenty of SP MK 2's in entry level classes and for argon regs when diving dry. Scubatoys sold em for $49 a few years ago when they dropped SP. I stocked up.
I would not use it deep, or in cold water. Too many better choices. Why take the chance?
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