Minor Rant about DIN 1st Stage Dust Cap

[certainmisuse]

"Dust Cap"
Why would anyone expect it to be water proof?

I think it's what the manuals say that causes confusion/concern.

 

[MichaelMc]

Past posts said that pressurizing the system presses the o-ring into the corner of its grove and seals it there, as designed. Just smushing an o-ring with a screw on cap does not achieve the same effect.

That said, I've soaked Yoke with a cap on tight, and apparently broke the cap that way. And soaked DIN with a screw on cap, and separately found water in my high pressure chamber. ...?

 

[Divectionist]

The dust cap that came with the MK17Evo is not to be trusted to keep a watertight seal. The aftermarket screw-in caps that keep screwing until hitting the O ring, and can then be turned tight to form a seal, are good to go.

The MK17 is sealed so it is sufficient to rinse it with running water, although I do dip it in the water briefly sometimes, as I trust the seal of the aftermarket cap. You can still dip it in a way that keeps the valve opening out of the water. I never found any droplets inside.

If you then keep the 1st stage above the water and have the second stages etc. sitting in the water to soak, you'd be very unlucky to get any water up the hoses against the closed airspace, and anywhere near the 1st stage.

I keep the original dust cap attached because it's a convenient storage cover post-drying that can be flicked off before attaching the reg for the next dive. The aftermarket cap I keep unattached to the 1st stage so I can keep it dry and put it on whilst swapping tanks on a boat etc., and then again for rinsing, always making sure it is bone dry inside.

I keep the screw in cap with a small towel inside a little dry bag to take on boats.

 

[doctormike]

Very few divers that own their own regulator also own a cylinder, much less a tub large enough to,place one in. But failure to soak the salt out of a regulator after a vacation trip absolutely can result in premature deterioration of gear, or add a bit of a challenge to the next service.
Yes, you want to be sure to not press the purge while soaking unpressurized. There are also some brands with a “seat saver” feature that require a different protocol. Keeping the 1st stage higher than the 2nd stages is good advice either way.
Most yoke dust caps really are intended to make a water tight seal for soaking and rinsing. My DIN set gets soaked with the yoke adapter and dust cap in place.

You don't have to put the whole tank and first stage in, right? Just soak the second stage attached to the tank if you aren't happy with just flushing it with running water, and you want to soak it.

You don't need to soak the first stage, just running it under the hose should be OK. It's the second stage that is gonna have places where salt water can hide and dry. I wouldn't want to soak a first stage and rely on a dust cap. If you have a bad O-ring on a pressurized system (DIN or Yoke), you are going to know it from the gas leak. But how would you be sure that your dust cap seal was really watertight for a long soak?

Again, not an expert, correct me if I'm wrong. But I think that the key is to run the second stage under the hose to flush out the salt water before it dries. If you let it dry before rinsing, then maybe you should soak it.

Dunno, I have been doing it that way for 20 years, no soak, just a good flush with running water. Multiple regs, never had a problem, never a bad report when they were serviced.

 

[Bigbella]

Been soaking DIN regs with only the 'dust' cap for over 20 years. No problem.

Interesting people think you can screw a DIN reg into a tank and seal it against 3500psi-no problem, but get very concerned about screwing a dust cover onto that same DIN and putting it in a tub of water with trivial pressure differential.
Unless it's not made well they are designed to seal.

The seal, while under pressure is far more secure than when simply clamped to a tank or dust cap; and photographers will tell you that the biggest danger to their housed cameras, are to their static or dynamic o-ring seals, while at the surface -- relatively unpressurized..

Do not count on delrin plugs for DIN tanks; they are seldom ever watertight. I routinely service rigs which were clumsily soaked in that manner; and there are indications of water intrusion more often than not. Soaking your regs while pressurized is the best solution . . .

 

[W W Meixner]

Hey Doc...

As has already been stated...I too have been soaking/hose flushing 2nd stage regulators for years with no water intrusion problems...the key is not to press the purge button on the 2nd stage if it's not pressurized...the knife edge will seal out water against the LP seat...no problem...

For all DIN 1st stage applications...push/pull ''dust caps'' should be replaced with threaded DIN caps...with the hanger strings threaded through a diagonal drilled hole in the end of the cap...if the caps are of the type that are not drilled through...they will provide a water tight seal against the captured ''O'' ring on the male DIN fitting...soak and hose flush to your hearts content...

Delrin versions are the best...Delrin is very stable...not affected by heat/cold expansion/contraction...

Four dollars at DGX...plastic versions are $2.

Dive shop dunk/rinse tanks are only clean in the morning...if then...when salt water diving the most important thing when rinsing...regardless of what it is...to clean while everything is still wet...if you wait until everything has dried...and salt crystals have formed...you've waited too long...and you've just started a love/hate relationship...your gear will hate you...the dive shop service departments will love you...

Best...

Warren

 

[fmerkel]

I'm a photographer and don't believe that stuff about the cameras being more vulnerable under less pressure. That may been true on some of the equipment that actively relies on pressure to help seal, but the clamshell type derive no benefit from it.

I think the issue with that is jostling in the dunk tanks.

 

[markmud]

Hi OP,

I soak my regs u/w while under pressure only. Din or yoke. Water infiltrating upstream from my second stages is my biggest fear.

I have pony bottles. I soak the reg/pony combo in my basement kitchen sink. I have soaked a full-size tank in a tote bin full of water with a regulator attached. I like soaking my steel tanks to make sure all salt is dissolved from the boot area and around the neck where the O-ring does not mate.

I know...I am OCD and anal retentive at the same time. But, I am happy with my life as is. I hope all of us can accept our personal flaws.

markm

 

[MichaelMc]

I stole an idea from bone and got a $9 one gallon pump pressurized sprayer from Home Depot and hose down my kit once I take it off. (And soak all of it at home.)

HDX 1 Gal. Sprayer-1501HDXA - The Home Depot

Though if you’re packing a sprayer into the car, it might as well hold two gallons of fresh water, not just one.

 

[markmud]

I stole an idea from bone and got a $9 one gallon pump sprayer from Home Depot and hose down my kit once I take it off. And soak all of it at home.

HDX 1 Gal. Sprayer-1501HDXA - The Home Depot

Though if you’re packing a sprayer into the car, it might as well hold two gallons of fresh water, not just one.

I have thought about that.

I usually refill water bottles with tap water while on dive trips. I use the bottled tap water to rinse my first stages before changing tanks during the SI. I then use the remaining water to rinse the regs from top-to-bottom before depressurizing while on the boat ride back to the dock after the last dive.

cheers,
m