US Divers Metal second stages, Why not?

[Scott G. Bonser]

Kirby Morgan offers a composite, adjustable version of the Connie, complet with hard boxtop and purge valve!

I have purchased the Kirby Morgan guts, specifically the diaphragm, roller demand lever, inlet seat and exhaust valve and Exhaust Tee; and installed them into my metal 1085's. I also purchased a new, OEM, Aqualing rebuild kit to get Apples to Apples comparisons of the KM and Aqualung parts and they match up. The KM diaghphram outer Edge is nearly 2x as thick as the Aqualung. It fits perfectly otherwise and works well but that extra material makes installing the box top clamp a bit more of a workout than normal.

I have a bunch of cracked plastic Connie 21's and one of theses days im going to buy a KM replacement body to see if i can assemble a set of "New" Plastic Connies to be my travel rig. Im realy curious to see if the original, threaded diaphragm cover on the old 21's screw into the KM housing to complete that full vintage look.

 

[Scott G. Bonser]

Thx, PartFish. KM always a reliable source..

 

[John C. Ratliff]

This reminds me on another one of my favorite metal second stages, the Voit MR12-II [Bullseye purge button]. One of the most beautiful second stages ever made, and with that Venturi tube a great performer. Mares continued the line for years, eventually morphing into the Abyss, all fine and well. However recently, probably because of SP, Mares started to add features that were not really necessary. By this I mean the adjustable breathing knob, which I will call an unnecessary complication to a near perfect design. IDK, just my opinion on the demise of one of my favorite second stage designs.

The only thing I don’t like about the MR12-II is that they tend to freeze up and free flow in very cold water.

SeaRat

 

[Scott G. Bonser]

The only thing I don’t like about the MR12-II is that they tend to freeze up and free flow in very cold water.

SeaRat

…mine as well. I have two that I have for octo regs that I overhauled. Some parts not easy to find, but I did….

 

[USdiver1]

The only thing I don’t like about the MR12-II is that they tend to freeze up and free flow in very cold water.

SeaRat

That is what the US Divers Supreme silicone cold water kit prevents. [See my post #33 above].

 

[Nemrod]

Today I glided over the reefs of Cozumel sipping air from an extraordinary G250 Graphite/Mark 11 that is so effortless and sublime it is simply the best.

But, I would still be in the the market for a titanium and composite Conshelf 14, call it the 14TA (titanium adjustable) with adjustable orifice and adjustable spring tension with the KM roller lever. Really the legacy Kirby Morgan is 90% there. Thing is, there is the regulator called the G250!

On the flight down I watched what might be the stupidest movie ever, King Kong and Godzilla!!!!! The G250 is the Godzilla of regulators, the Kirby Morgan might be the King Kong. King Kong is just a big monkey, Godzilla has atomic bad breath and is like a lizard bad aXX!

And the movie is awful, I should have asked the flight attendant for a barf bag but was afraid they would toss me off the airplane so I managed to hold it back.

 

[John C. Ratliff]

That is what the US Divers Supreme silicone cold water kit prevents. [See my post #33 above].

Not really, as the US Divers Supreme silicone will prevent ice-up on the first stage, but the problem with the MR-12 II (and the III) is that the Venturi tube is exposed to the very cold water, and forms ice in the second stage, causing the leak. I noticed this decades ago in a lake dive on the Oregon coast.

SeaRat

 

[Nemrod]

Not really, as the US Divers Supreme silicone will prevent ice-up on the first stage, but the problem with the MR-12 II (and the III) is that the Venturi tube is exposed to the very cold water, and forms ice in the second stage, causing the leak. I noticed this decades ago in a lake dive on the Oregon coast.

SeaRat

And the Venturi of the 1085 second stage is just as effective as that of the MR, maybe more so.

Going back in this thread, yes, USD/AL did suggest that the 1085 type with the two screw exhaust tee be retired. The exhaust valve is too small and is exhausting if I might say, sort of like blowing up a balloon, after a dozen or so it is tiring. My two are retired to pool duty or demo purpose only as I have had them since childhood. The later 1085s with the large exhaust valve, be it the plastic tee or the wraparound tee, are completely adequate regulators.

Two, two screw 1085s:





And two no screws 1085s:

 

[John C. Ratliff]

Nemrod, we were issued these Calypso regulators while in the U.S. Air Force Pararescue in 1968. I have used them in many different dives during my service days. I never had the same impresssions you have of the smaller exhaust. I think if you look at the U.S. Navy Experimental Diving Unit’s tests, they were rejected by the U.S. Navy, mostly because of the difficulty with the exhaust at depth. We in the USAF rarely used these regulators beyond 120 feet (we had a quarterly requirement to dive two dives, and one had to be beyond 60 feet). So I don’t have the same impression as you about the smaller exhalation opening.

That said, the best regulator I have ever dived is the Scubapro Pilot, and the next best the Scubapro A.I.R. I. Both these regulators have the entire surface of the inhalation diaphragm as the exhalation opening. You simply cannot beat that.

SeaRat

 

[Nemrod]

Here do this, Mr. John, put on your running shoes and get a straw and stick it in your mouth. Now take off running, breath in through your nose and then ONLY exhale through the straw! No cheating, in through the nose, out through the straw. Tell me how far you get. Well, your neighbors might call the funny men, hey, that fin swimming dude has finally gone off the edge . Yeppers, that would be a good simulation.

The Navy might not have noticed it but as a 12 yo I probably did not know any better and the 15 feet depths of Steinhatchee, Florida were more my depth limitation that a stiff neoprene dime size exhaust valve inside a rudimentary restrictive tee, oh, and my mother's booming voice, Jimmy, you come up from down there right now and I mean it!!!!! My mom was not in the Navy, had she been, she would have told you guys the same thing, get your axxes back on this boat right now you frog men .

Yeah pool duty. I was chasing a large green moray Monday, free swimming, into the usual too strong Cozumel current, my G250 was huffing and I was about to go into grey out, the thought of doing that with an old two screw 1085 makes me think I would be dead now, not typing this as a tropical storm beats down on us . I need a day or two to dry out anyways.