Why is a Conshelf so reliable long term?

[herman]

Alright, well.. I'm curious and they seem to be cheap. Which model is the good conshelf? All of them? I see XIV, 20, 21, 22, SES, SE2 on ebay. Are they all created equal (or close)?

If you are talking about the first stage, the only difference between all of them are more to less cosmetic external differences. The very early ones had lighter yokes but will still handle 3000, the later yokes can be put on them, some of which were marked 4000psi (most were 3000). The very early ones also used a yoke retainer nut and yoke as opposed to a threaded yoke but even those parts are interchangeable and from a performance standpoint are cosmetic.
Port size and number of them is the real difference between them. The early ones had a couple of LP ports, later ones had more LP ports and some even had 1/2 LP ports (you need 1/2 to 3/8 adapters to use these with standard hoses). The HP ports were 3/8 in the early models and 7/16 in the later ones, again really cosmetic, adapters can be used to go either way if you like. The later SE3 also had a removable HP seat (same one as in the Titan). Performance wise, there is no difference in them, the second stages are a totally different matter.

 

[Nemrod]

When people ask about bullet proof/bomb proof regs almost exclusively either the conshelf or MK2 are mentioned and not much else except the occasional shout out to some Sherwoods. On SB the conshelf seems have attained legendary status, not saying it's underserved but "perhaps" there are others worthy of equal status.

No, the "others" do not have the longevity in the market and in use. They do not have the parts support either or they have some other complication that resulted in their being also rans instead of the King of the Hill.

N

 

[Nemrod]

Alright, well.. I'm curious and they seem to be cheap. Which model is the good conshelf? All of them? I see XIV, 20, 21, 22, SES, SE2 on ebay. Are they all created equal (or close)?

The brass and chrome one, the latest version, which still spanned years and years with little change, the XIV/14.

I look for the ones with the nylon feet on the lever, the grey silicone diaphragm, slip on exhaust tee, and for the first stage the very last ones with the "normal" hose routing. I also prefer the final exhaust T that was on the 14. Of course condition is everything.

My early, 66 (?, I forget exactly when I bought it) has the tiny exhaust valve and the screw on exhaust tee that most people for some reason installed upside down.

N

 

[buddhasummer]

It'll be interesting to see what's still about relatively unchanged in 20 years, unfortunately I'll likely not be around to see.

 

[Centrals]

Any modern copy ie. Conshelf, available in the market?

 

[rhwestfall]

it's more the "brain wash" that you need to annually service them.... then again, some of the plastic crap these days.....

 

[buddhasummer]

I have two such second stages, gray diaphragms, nylon on the levers with new stock OEM kits, new decals, new 14 exhaust Ts, new exhaust diaphragms and re chromed face plates and clamp rings. I also have a very good condition XIV 1st stage with 3x3/8 LP and 1x 3/8 HP port with new stick OEM service kit. It's a project I started but will likely not complete as I now have brand new ones. I'm going to sell the project as a whole if anyone's interested. It all needs to be put together etc it's in pieces.

 

[buddhasummer]

Any modern copy ie. Conshelf, available in the market?

A new Conshelf 14 with 4/ 3/8 LP ports and 1x 7/16 HP port, if you know the magic hand shake they can still be purchased new.

 

[Luis H]

Iain (post #20) hit one critical design feature that that has not been mentioned. The HP seat design. I didn’t follow some of the rest of the post, but the points about seat design is extremely important when talking about long term reliability.

The early Conshelf’s and Royal Aqua Master used a hard rubber seat. I used to service them a lot in the 70’s. When they worked, they were extremely reliable a lasted a long time. I have tried 40+ years old Conshelf that still lock the IP like no other regulator.

That wasn’t always the case while servicing a regulator back in the 70’s. Some of the rubber seats just didn’t work well and there has been more than one regulator that I had to try 2 or 3 seats before the IP held good enough to send it out the door.

I should add that IP gauges were not as common back then. We did not attached them to the QD hose… We didn’t have QD hoses. We had to attach them to a second 3/8” LP port if there was one. So IP checks were not done as often and a bit of IP creep was acceptable a probably very common.

Variations in the volcano orifice would have had a big effect, but the hard rubber seats were definitely not always reliable, but when they were, they would last for decades.

Fast forwarding to the late 80’s or maybe early 90’s. US divers (now Aqua Lung) went through a big research/ development project for the new seat material. I am not sure how long it took, but the new blue HP seat is a close to bullet proof as a seat can be.

I am not as familiar with the Mares line, but because their heritage/ roots of some of their first stages, the seat design in the MR-12 (and I think a few others) is interchangeable with US Divers/ Aqua Lung. Mares also went to a seat development program and they came out with what they call their “tri-material” seat. I have not used it, but my understanding is that it is just as reliable and long lasting.

Now you can also buy an aftermarket seat from Trident (and there are other sources) that will fit Aqua Lung and Mares. Some are now as reliable as the Aqua Lung seat, but AFAIK Aqua Lung seat was the best for a long time.

When I designed the Argonaut Kraken, I made a conscious decision to use the most common seat design available. The manufacturer (VDH) was not going to have the resources to source a new seat design and to be honest, why re-invent the wheel. My understanding is that Bryan (at VDH) now has a new supplier for very reliable seats, but the material science behind the seat synthetics is probably not a secret anymore.

I should add for the piston regulator fans (I used to be one). The seat in most piston regulators tend to be much thicker and they used to be just a solid chuck of Teflon (or similar).

 

[Centrals]

A new Conshelf 14 with 4/ 3/8 LP ports and 1x 7/16 HP port, if you know the magic hand shake they can still be purchased new.

I was wondering if the Conshelf is so good then why no one is making(copying) them? Surely the manufacturers in Republic of China should have known about it.

Thank you for the offer but I love my Apeks.
The seats in both Apeks 1st and 2nd stages are the weakest link in the whole set up. There must be some reasons for choosing inferior material!! The dealers have to earn some money every now and then!