SP MK25/S600 Freezeups

[roamer]

Most folks seem to run an S600 off of one SP's piston first stages. Conversely, I tried running it off from a MK18 diaphragm 1st stage and have had similar problems. I was never sold on running a piston reg in the Great Lakes, with all the particulate in the water. It is possible, as Genesis states, your piston 1st stage may have froze. It may behave much differently than a diaphragm 1st stage. One thing I will note, the S600 was much worse when already wet from a dive.
I hate to tell u this netmage, but I had the excellent tech at our LDS tweak and fiddle with that reg multiple times. It just isn't a deep and cold reg, that's my opinion. This is based on seeing and hearing of multiple people with the same problems. I know I have had great luck with the Poseidon Jetstream 1st stage coupled with Poseidon's Odin 2nd stage primary and octo. They have taken me places the S600 hasn't. I have heared good things about Apeks. Anyone else know anything on those?
After thinking about it won't be hooking up an Odin to my MK18, with the S600 as an octo. The slightly higher IP with the S600 would be suicide. Probably buy an another set of Odins and hook them up to the MK18.

 

[Genesis]

I have had mine down to 140 without a single hint of trouble. It breathes just fine when deep.

However, cold is another matter.

Seconds can freeze. All-plastic ones can freeze more easily than metal ones, all other things being equal, simply because if your exhaled breath (which has quite a bit of moisture in it) gets cooled by incoming gas sufficiently, the water will turn to ice and that ice can jam the mechanism.

A metal air tube and/or other metal parts tend to work against this, in that they absorb some of the heat from your breath and re-radiate it into the incoming air stream, thereby tending to melt any ice that would otherwise form.

Piston firsts can freeze too, for a slightly different reason but the effect is the same (ambient water freezing .vs. water vapor in the air in the regulator's second stage space freezing)

For cold water, these simply aren't the regs I'd choose.

 

[roamer]

One other point I forgot to mention netmage, especially if you continue to dive the S600. A 30 or 40 cu ft pony bottle with regs (aka redundancy) I carry one anytime I have the possibility of going below 60ft in fresh cold water. It's my best buddy

 

[roamer]

Same here Genesis, 131' in Truk on the S600 no prob. 84F water temp. I concur on the the cold, it just isn't its territory. What's your opinion on the SP MK18 1st? Seems like mine have always been good, after all diaphragm is tried, tested and true I would think.

 

[roamer]

Apology Genesis, u already answered my question earlier.

 

[Genesis]

for its piston firsts.

If you want a diaphram reg, consider a brand that has built its reputation on those. Apeks comes to mind....

 

[DeepScuba]

As much as I appreciate and accept Genesis's knowledge, which I refer to constantly, it seems...............

I beg to differ for one reason..........I have done about 2 dozen dives on my Mk20/G250HP.......actually I SHOULD be saying Mk25's but I get used to writing Mk20.......sorry for my previous posting errors, but as stated, tehy are the same reg with the exception of about 3 pieces......

I have NEVER dove them at tepertaures ABOVE 50 degress, and I can say I've never had them free-flow/freeze.

I have been down to 200ft, and as cold as 38-39 degrees for sure........but probably colder, I just can't remeber the specifics, cause DAMN it's cold enough anyways!!!!

Mine have the composite piston...my IP is 140PSI (high end of spec), my 250HP are wound to full BREATHE position , an I am not known to inhale lightly...read HOOVER

tehe


So what gives???

I am not alone, as I dive with several other SP piston divers, either S600 or whatever else for 2nd's and we have not had a single problem.

Maybe our LDS IS giving very dry air???? Maybe this one-sided anti-piston thread is getting a little over-done??

I dunno, but first hand experience being what it is, and in colder conditions more regularly than most here, I can only think that we would have had a certain amount of freezes if it really was that much of a problem.

I dunno.........

As I've mentioned before, I've even felt the "Ice-chunk" thing happening in my mouth once, but no other problems. And that was in 110ft of damn cold water..I nearly froze my nutts off.

Now Mares Axis free-flows.....there's a problem most divers have seen...........


Comments Genesis????

 

[Genesis]

and the 101st it burns you.

The problem with freezeups is that much matters on the particulars of the dive, especially with firsts.

How the reg is mounted, how much water flow through the balance chamber happens (more = better), salt .vs. fresh water (salt = harder to freeze), how much breathing you do, how careful you are not to inhale and inflate the BC at the same time (or not), if you ever have an OOA where you have to donate air (double the flow instantly, or perhaps even more), etc all matter.

I like the SP 1sts, especially the older ones (the Mk10 and MK10+ in particular.) Simple, solid, excellent materials, fairly direct airflow path, etc.

Composite pistons, by the way, aren't completely composite, unless you've got something that I haven't seen (quite possible.) The "composite piston" is a sleeve over the big end that (in theory) keeps water away from the big end's metal part. There are a pair of O-rings that theoretically isolate the metal (which is the cold part) from the water, thereby preventing freezes. In theory.

The same theory applies to the funny sleeve they put in there on the piston shaft for the HP O-ring end.

The problem with all this is that its theory, and far too many people have these things freeze on them in cold water.

I don't dive cold water, but if I was to schlep my dry suit up to the north some time, I would bring a diaphram first, and my G250s for seconds (metal airtube.)

 

[DeepScuba]

No it's the same composite that you have, or have seen.
Sure I know you're gonna say 100 dives OK, 101 dives BURN>>>>

But, like I've said, i have lots of guys doing lots of dives in lots colder water and ZERO on the freeze-ups!!

I think it's way over done, or you guys have pooched set-ups or you guys have high moisture air or, or ,or.......I dunno???

Almost all fresh water (Especially the coldest ones)

Like I've said, I'm a bit of a Hoover.....

My adjustments are FULL OPEN

My IP is 140PSI (high end)

I guess, like I said, I DO DIVE cold water, all the time, all year long. Stinking ICE diving!!!!!

I am the guy that it's supposed to happen to, me and my buddies, in droves it should happen, and it doesn't. I'm actually going to TRY and make it happen......

I'll keep ya informed.

 

[Soggy]

I've also had no problems with mine in cold (38 degrees) and deep (100+ ft) salt water.