Piston regulators and the environmental goo!

[beanojones]

Corrosion is corrosion, tropics or elsewhere, if you dive it a lot, then clean it a lot.

N

The air itself is salty in the small island tropics. (I guess it is imprtant to add the "small island" tropics.) Cars rust through from the top down here. Even if it rains every day, and it does, the air itself has so much suspended salt spray, every thing rusts/corrodes/craps out. Same with rinsing, I guess.**

Pistons crap out. I have retired personal gear and overhaul'd gear from piston crap out. I have never had to retire diaphragm 1st stages from the same thing.


**But really why shouldn't the gear be made to handle not being rinsed? Why should I have to make up for a materials (or design) defect? In my particular case, 'proper' rinsing won't even help. But in general, why not just make the gear out of proper materials, or make it so the fragile bits are never salt water bathed?

Just got back out here to the wilds of the Pacific, and someone gave me a reg back that I had given them for storage that I had completely forgotten about. Stored for 5 years, maybe. Apeks tx100 first stage, Atomic Ti second, Oceanic console. Rinsed before storage. THe Ti second stage is pristine. The hoses fitting are crusty and green. The SPG needle rusted in half. The TX100 is etched in green.

 

[beanojones]

Some but not all diaphragm regs are environmentally sealed. In "unsealed" diaphragm designs, the spring and spring pad are still exposed as they are in the unsealed ambient chamber - but the seat carrier and other moving parts are on the sealed side of the diaphragm as it is an upstream design.

The bits that are exposed environementally even in the old style (pre Apeks) Dipahragm design are
1. Cheap
2. Not moving

Compares this to the mk10, where the salty sandy Large piston o-ring is scraping away at the the wall of the reg.

 

[fnfalman]

The air itself is salty in the small island tropics. (I guess it is imprtant to add the "small island" tropics.) Cars rust through from the top down here. Even if it rains every day, and it does, the air itself has so much suspended salt spray, every thing rusts/corrodes/craps out. Same with rinsing, I guess.**

Pistons crap out. I have retired personal gear and overhaul'd gear from piston crap out. I have never had to retire diaphragm 1st stages from the same thing.

Beano,

If memory serves, you have a preference toward Atomic regulators, especially the titanium ones. But aren't AA regulators all piston operated?

I'm not trying to bust your chop here but I'm trying to understand your experience vis-a-vis regulators longetivity in the tropical area.

 

[beanojones]

Beano,

If memory serves, you have a preference toward Atomic regulators, especially the titanium ones. But aren't AA regulators all piston operated?

I'm not trying to bust your chop here but I'm trying to understand your experience vis-a-vis regulators longetivity in the tropical area.

I only use their second stages, and their alternate inflator regs. (Anyone want to buy four Atomic brass first stages cheap that I got for the B1 (Ti2) second stages?)

I was a big fan of Apeks firsts when they were the only truly, fully env-sealed first stage. If I was buying new (I cannot afford to, but if I was), I would be going for the Oceanic or Aqualung sealed diaphragms with the DVT/ACD.

 

[redacted]

The hoses fitting are crusty and green. The SPG needle rusted in half. The TX100 is etched in green.

Hose fitting and other threaded connections are just very difficult to clean. Pressure drives the SW into them and about the best you can do without disassembly is dilute it. A good coat of lube on those threads is probably especially important in your environment where it may never fully dry. But the SPG needle is a little surprising. The SPG is sealed as well as any sealed diaphragm. But once the seal fails, the internal bits probably have little to no resistance to corrosion. So once that seal fails, it's days were numbered even if it were in Arizona.

 

[DA Aquamaster]

The bits that are exposed environementally even in the old style (pre Apeks) Dipahragm design are
1. Cheap
2. Not moving

Compares this to the mk10, where the salty sandy Large piston o-ring is scraping away at the the wall of the reg.

In theory you are correct that the o-ring bearing surface is potentially exposed. In practice it is very rare for either the piston stem or piston head o-rings to fail for that reason. Rare as in I have never seen it in a reg serviced on anything approaching an annual or biennial basis.

If a leak occurs it is more likely to occur due to corrosion of the bearing surface in the swivel cap itself - and that is a cheap part to replace on a Mk 5, Mk 15, Mk 20 or Mk 25.

More importantly, the Mk 20 and Mk 25 use a piston with two piston head o-rings. The first does the work and the second serves as both a scraper o-ring to keep the surface clean and as backup in the event the primary o-ring failed. The range of piston movement is such that the primary o-ring never reaches the portion of the swivel cap not fully protected/sealed by the back up o-ring.