Second stage issue caused by flying?

[boulderjohn]

The shop that has serviced my regs in the past has a policy that the reg owner gets a free post service pool practice session to check things out.

 

[Merfman]

Thanks to everyone for your replies. You've confirmed our concerns as well as our intentions to our LDS.

Additionally, I've contacted the TSA to confirm if it's their policy to dismantle regs in search of contraband, so I'm assured a full body cavity search on my next trip. If anyone is interested, I'll post the answer I get from them.

Thanks as well for the advice of testing the regs post service, it will be done henceforth.

 

[Thalassamania]

Better still, when you get new regs ... get HOG. There's a company that actually supports consumers with classes and parts so that they can service their own regulators.

 

[Doubler]

I have heard of 1st stage issues after flight, supposedly caused by some kind of internal pressure differential occurring if the dust cover is on tight. I have never seen or experienced it myself but would believe this more than a 2nd stage diaphragm moving.

 

[Thalassamania]

The potential energy available, even if you took the regulator to hard space is only 1 ATA times the area of the first stage diaphragm or piston cross-section, not much.

 

[fire_diver]

I have heard of 1st stage issues after flight, supposedly caused by some kind of internal pressure differential occurring if the dust cover is on tight. I have never seen or experienced it myself but would believe this more than a 2nd stage diaphragm moving.

If a first stage could be damaged by that change in pressure, then it would explode when exposed to the 3000 (or more) psi from a tank.

 

[Mr Carcharodon]

1) Ever hear of a second stage malfunction due to airline flights?

2) Ever heard of TSA agents disassembling a second stage, either for:
A) Stealing titanium?
B) Searching for contraband?

Inquiring minds and all, thanks for the info in advance!

Your second stage works because there is a different pressure on either side of the diaphragm. Once you take it out of your mouth (like when you put it in your luggage) the pressure is the same on both sides. So at that point there is no force acting on it, which makes it unlikely to move, or break. The reduced pressure of the flight is of no significance because the forces are always sum to zero.

Stealing titanium in your second stage? Seems like you would need an awful lots of bits and pieces to make that work out. Besides which does an S600 even have titanium in it? Sounds pretty contrived.

Searching for contraband. Who knows. I did come back from Hawaii and find a TSA sticker on my backplate. Apparently they x-rayed my checked luggage and then opened it to check it out. Scuba gear often gets a good look, but I think they are mostly looking for dive knives in carry on which apparently people forget about.

By the way there is a simple check you can do to verify the diaphram is seated. Attach your regulator to a tank that is turned off. With the second stage in your mouth inhale. You should feel the vacuum, and it should not leak down over time. If it does you've got a leak. Of course the shop really should test your regulator after putting it back together. Sadly that seems not to happen fairly often.

 

[Bubbletrubble]

By the way there is a simple check you can do to verify the diaphram is seated. Attach your regulator to a tank that is turned off. With the second stage in your mouth inhale. You should feel the vacuum, and it should not leak down over time. If it does you've got a leak. Of course the shop really should test your regulator after putting it back together. Sadly that seems not to happen fairly often.

You can do the above test without attaching the reg to tank. You just need to make an air-tight seal over the first stage orifice. A properly placed thumb or an air-tight dustcap would do the trick.

FYI, an improperly seated 2nd stage diaphragm is not the only thing that can cause a vacuum test failure as described above. Other issues include: missing/defective o-ring, cracked case, torn diaphragm, bent back/defective exhaust valve.

 

[Merfman]

Quick update from the TSA: Let's just say they didn't seem to be able to distinguish the difference between SCUBA related regulators and personal respirators. I specifically asked if SCUBA regulators were disassembled and got an answer regarding personal respirators. Horse is dead, no use in continuing the beating.

 

[moregooder]

Find a new shop!