What is the most bulletproof 1st stage of all time?

[Jake 10]

ScubaPro hands down. Best overall customer service response, reliability, quality , and performance

 

[Nemrod]

No brainer, there are only two candidates.

The USD/AL "Conshelf" type first stage that was first found in the Royal Master DH regulator and then the Royal Aqua Master and then the Conshelf and then, leaving out several models, and then Titan LX and now the Core and the Legend (of all gens) with some extra parts for depth compensation. I can pretty much take them all apart and throw the parts on the table, mix them up and then reassemble them. And, the thing can live in saltwater without rinsing or cleaning even in the non-sealed versions. The sealed versions have been known to go decades without service. Sand, salt, no problem. A new ACD Supreme version might go forever without service, who knows!

The other would be the Scubapro MkV and it's many clone copies and up to the current Mk25. Does need to be rinsed and cleaned, does not like sand and salt though there are some sealed versions. If diving in sandy and foul conditions I slipped a bicycle tube over the holes and then poked a tiny hole with an awl. Kept the sand out. And the original turret had an issue that generated a recall.

There is an esoteric argument that with diaphragm regulators the seat is pushed open against tank pressure and it could fail closed. With piston first stages tank pressure pushes the seat open so it would fail open. Sorta like that. Esoteric.

N

 

[AfterDark]

I know little about servicing 1st stages. The Scubapro MK10 wasn't so bad, learning how to service it as a beginner & I ended up buying a collection of those. The MK5 and MK10 are nearly identical as far as servicing and layout goes.

The MK15 on the other hand ..... hell no! Can't find service kits for it anywhere, and it has a weirdly complicated brushing system. I mean, it looks like a nice regulator, just not to service & I traded my MK15 for a MK10.


"Today on Demolition Ranch, we're testing first-stage regulators. The question is, can first stage regulators be used as body armor? As usual, we'll be starting with a 22 caliber...."

I brought a MK15 to LDS owner that I've know all of his life and trust him. He told "waste of your money and my time".

 

[ThatDogDontHunt]

I assume you mean 'unbalanced' not 'unplanned'. The answer is no. The sherwood with a clogged dry bleed valve will not accurately compensate for depth changes, which makes the regulator almost useless at any sort of depth. I believe that you are confusing environmental sealing (that's the dry bleed part) with depth compensation, something that all regulators need in order to work. With the Sherwood design, as ingeniously simple as it is, if that little valve gets clogged, the pressure in the ambient chamber won't equalize and as a result you have no (or very sluggish) depth compensation.

For any regulator to work, IP must remain reasonably constant over whatever the ambient pressure is at a given depth.

I believe the reality is that a clogged Sherwood dry bleed works just fine at depth.

The small plastic one way valve is NOT capable of sealing out ambient pressure without the bleed air pressure behind it. It will let water in starting at very shallow depths - less than 30 feet.

The reason I know this is due to a LDS service tech doing a christolube pak of a first stage. The reg dove fine for a whole vacation week of dives, but had no "air leak".

That was when I started to service my own regs.

It required a bit of clean up afterwards since the ambient chamber was full of salt water. But that is fairly easy to do as the cap can be spun off by hand, no tool required.

 

[halocline]

I believe the reality is that a clogged Sherwood dry bleed works just fine at depth.

The small plastic one way valve is NOT capable of sealing out ambient pressure without the bleed air pressure behind it. It will let water in starting at very shallow depths - less than 30 feet.

The reason I know this is due to a LDS service tech doing a christolube pak of a first stage. The reg dove fine for a whole vacation week of dives, but had no "air leak".

That was when I started to service my own regs.

It required a bit of clean up afterwards since the ambient chamber was full of salt water. But that is fairly easy to do as the cap can be spun off by hand, no tool required.

Thanks, that makes sense to me. The one I had problems with was the genesis 1st stage with the schrader type valve.

However, in both cases, the reg might compensate adequately on that dive, but it's likely to damage the reg as a result, because the salt water (as you pointed out) is going to remain in the ambient chamber, and that could be pretty corrosive in short order.

 

[Hunter69]

Aqualung Conshelf XIV. Easy to work on, durable and reliable. Tried and true!

 

[Golan68]

MK2 not only because of it's simplicity but rather because both 2 orings "see" low pressure. making it very safe for oxygen too. mares R2 is even one less oring at the yoke retainer [something seen even before "Healthways"]. The thing is that I will probably use Mk20 just becuse of the best flow. as far as design you should see the internals of a Drager Shark.