Wanting to Service My Own Regs

[halocline]

If I have the early version MK-10 with the really small ambient holes, I assume that it must be packed with silicone grease as the holes are not large enough for proper rinsing and water flow. Is this correct? Is there a nitrox-compatible equivalent for this process?

Are you sure your reg is not a late model MK5? I've never seen a MK10 with the small ambient chamber holes. According to the photos in the scubapro museum, the latest MK5s had the tiny holes, no early MK10s did. To make it a little more confusing, the photo of the latest MK5 has the yoke knob, while the earliest MK10 has the old-style yoke screw.

Anyhow, I've packed one of my MK5s with tribolube, I think it's #66. It's the heavier (and cheaper) of the two types of tribolube. It holds pretty well, I bet silicone is a little stiffer. I mostly did it out of curiosity; as awap said, there's no problem keeping the ambient chamber clean if you soak. The best MK10s to pack are the later SPEC models that have the groove for the boot. Good luck finding a boot; it took me a long time to find mine.

 

[windapp]

It is a MK-10 for sure. It is, I believe the earliest model, and they did have tiny holes to keep the greese in. The later models had bigger holes with a SPEC boot. Thanks again for everyone's response. I like the idea of buying a cheep 1st stage to sacrifice as my practise reg, and maybe I would get some parts out of it (like a still-good piston) in the process.

So now a question. Which second stage is best for servicing and breathability a 109 or a Conshelf XIV. My wife can't stand the dry air using plastic regulators and I would like to get her a metal one. I am thinking the Conshelf is best for servicing since I can still get service kits. Can it be tuned to breath as well as the 109?

 

[herman]

All in all, the 109 is most likely best breathing of the 2, mainly because you can adjust the cracking pressure on the fly. Service kits are not a problem if you don't mind aftermarket ones (and I see no reason not to use them). Vintage Double Hose has started selling kits for the 109s (unbalanced and the balanced versions) plus he has the seprate parts for the Conshelf- since there are so few parts in it, there is no need for a kit. Looking at the site, he does not list the LP seat but since it is the same one that is in the DA Aquamaster and Roylal AM, you can order those, which he does stock. Single Hose Parts : Vintage Double Hose!, Your online source for all things related to vintage diving

 

[Zung]

I believe the quality of air delivery is related to the technology of the second stage: all my barrel poppet second's (109, 156, G250, M5) breathe better than my classic down stream's (R190, R290, R390 & AL XL).

Why, I don't know. Any ideas?

 

[halocline]

It is a MK-10 for sure. It is, I believe the earliest model, and they did have tiny holes to keep the greese in. The later models had bigger holes with a SPEC boot.

So now a question. Which second stage is best for servicing and breathability a 109 or a Conshelf XIV. My wife can't stand the dry air using plastic regulators and I would like to get her a metal one. I am thinking the Conshelf is best for servicing since I can still get service kits. Can it be tuned to breath as well as the 109?

The 109 uses current parts for a rebuild; you can convert it to balanced/adjustable and it's basically a G250 in a nice metal case. You need the G250 spring, balance chamber, s-wing poppet, and rebuild kit. The NOS kits you sometimes see on ebay might include the poppet and balance chamber. You also might do better with a current lever, but that seems to be variable from reg to reg. There was a lengthy and informative thread a while back on the lever generations for these regs. If you don't want to convert it to balanced, just use a G200 (duro) poppet, the original spring, and the current non-balanced seat.

I'd like to see a photo of your first stage. The SPEC boot generation of the MK10 has a big groove for the boot; all the earlier ones I've seen lack the groove but still have the same size ambient chamber holes. The late MK5s have tiny holes that are set in larger drillings.

 

[windapp]

I bought it on ebay so follow the link Scuba Pro Regulator | eBay. The first stage is in the third picture. As you can see, the ambient ports are on the body, which, according to what I have read, is the distinguishing characterstic between the MK5 and M10.

 

[redacted]

Yes, that is a Mk10. The confusion is the idea of "small holes". This is a picture of the Mk5 spec which had much smaller holes: First

 

[windapp]

The holes you are seeing on my MK-10 are actually the larger holes counter-bored in to the smaller holes. Up close, it is just like your picture of the MK-5.

New question. The Conshelf IV first is unbalanced correct? I was looking at the charts in the repair guide, and unless there is some sort of balance chamber hidden to me, it looks like a pretty standard unbalanced diaphram first.

Is an environmental seal necessary to prevent freeze-up of diaphram regulators. If it is necessary, what part would freeze if you didn't have it?

 

[halocline]

New question. The Conshelf IV first is unbalanced correct? I was looking at the charts in the repair guide, and unless there is some sort of balance chamber hidden to me, it looks like a pretty standard unbalanced diaphram first.

Is an environmental seal necessary to prevent freeze-up of diaphram regulators. If it is necessary, what part would freeze if you didn't have it?

The balance chamber would be right where the HP seat post ends, you probably already know that. I don't know much about the lineage of the conshelfs, but I do know that the US divers diaphragm 1sts descended from the Aquamaster and Royal Aquamaster 2 stage double hose regs. So, you could head over to vintagedoublehose.com and find schematics of both the aquamaster and royal aquamaster (RAM). If yours looks like the RAM, it's balanced, if it looks like the aquamaster, it's not. I've never heard of a non-balanced conshelf 1st, but again I don't really know the lineage. I'm certain Luis H on this forum (and vdh) would know.

Diaphragm 1sts are generally considered more freeze resistant than balanced piston 1sts. In both cases it would be freezing in the ambient chamber around the main spring that would cause problems, I suppose. In the BP design, the piston shaft runs through the ambient chamber, so there's cold depressurizing air moving very close to the water. With the diaphragm, the cold air is separated from the water by the rubber diaphragm, which I suppose is much more insulating than the thin metal piston shaft. Sealed diaphragm regs also seal off the ambient chamber with another diaphragm and either a liquid fill or piston to transfer the pressure to the internal diaphragm.

So, when you say "is it necessary" I guess the answer depends on how cold the water you're talking about using it in is. I'm sure there have been some instances of non-environmentally sealed diaphragm first stages freezing.

 

[herman]

All Conshelfs are balanced, the balance chamber is also the spring guide. They are decendents of the Royal Master and exactly like the Royal Aquamaster. There is a small hole running up the shaft of the HP seat (as opposed to the DA Aquamaster seat which has a solid shaft) that vents air into the spring carrier/balance chamber. It is sealed with an oring and a backup ring. The same design is used in the RAM double hose, all Conshelfs, Titan, SEA, Royal and Legend plus a number of other brand like Voit and Dacor.