putting diaphragm back in the 2nd stage

[reefvagabond]

So I dove a site that required me to crawl out of the surf during which I got some sand and rocks in my 2nd stage. I couldn't shake them out so I unscrewed the top, removed the diaphragm and dumped the sand/rocks out. I have put the diaphragm back and followed the instructions provided in the regulator's manual. It seems okay, however I would like some feedback because I have never done this before.



That's the instructions for my Dive Rite 2nd stage. Is it as simple as just laying the diaphragm on top and screwing the rest of it on? Am I supposed to do anything more, like does the diaphram have to be air tight when I put it on and if so how would I do that? Any recommended procedures for testing it after I'm done?

 

[DevonDiver]

Yep, it's pretty simple.

Don't over-tighten, or you can damage the thread.

Do ensure that the diaphragm is properly seated.

You can test the integrity by putting the regs onto a cylinder and trying to draw breath (without the cylinder on - you've got a closed system). If you can draw a breath through the regulator, then the system isn't closed (you've got a leak). I do this at the beginning of every diving day, as part of my kit assembly.

 

[herman]

Or just put your thumb over the inlet filter. You are looking for small leaks. Don't pull a hard vacuum, just a gental inhale to see if any air is leaking in. If not done, if you detect a leak you have to find and correct it. Overtighting is not likely to damage the threads unless you use a wrench but what it can do is twist the diaphragm causing it to leak. In any case, snugg is fine. You have now preformed rocket science on life support equipment.

 

[DevonDiver]

Overtighting is not likely to damage the threads unless you use a wrench

...or if you have good grip strength and the fine-motor skills of a clumsy gorilla. Ahem... :blush:

 

[Hatul]

I had the same problem: after crawling out on a shore dive, my pony reg second stage was packed with sand and I had to open the cover and flush out the sand.

Adam

 

[reefvagabond]

Thanks for the info so far guys. So with a closed system when I draw a normal breath I cannot, but if I try and breath hard I hear a bit of air seeping through the 2nd stage. Does that mean the diaphragm is not seated properly? I just put the diaphragm on top, didn't press the sides in or anything. I also tried testing it in the bath tub and it seems fine but don't know how it will handle under pressure.

 

[ClayJar]

I also tried testing it in the bath tub and it seems fine but don't know how it will handle under pressure.

The second stage body (diaphragm, exhaust, etc.) never has significant pressure across it. There's a significant pressure difference between the hose and breathing sides of the actual valve in the second stage, but the diaphragm and body will have at most a few inches of water pressure on them. The second stage is delivering air basically at whatever the ambient pressure is, no matter where you are, so unlike a first stage, there's virtually no difference what depth you're using it. If it breathes dry in the bathtub, it should breathe equally dry in that orientation at any depth you may scuba.

 

[LeadTurn_SD]

Thanks for the info so far guys. So with a closed system when I draw a normal breath I cannot, but if I try and breath hard I hear a bit of air seeping through the 2nd stage. Does that mean the diaphragm is not seated properly? I just put the diaphragm on top, didn't press the sides in or anything. I also tried testing it in the bath tub and it seems fine but don't know how it will handle under pressure.

If you hear some air seeping into the reg with a normal inhalation effort (assuming the reg is not on a tank):

1. Make sure the 1st stage dust cover is on securely. Make sure mouthpiece is zip-tied firmly.
2. Put your thumb over the end of the inflator quick release fitting.
3. Inhale with a "normal" amount of effort. Not like your trying to suck an egg through a straw

Sometimes you can draw a little air through the 2nd stage when doing the "vacuum" test, and it may coming from "elsewhere", so you need to check 1 and 2 above.

Repeat the test.

If you are still able to draw air, you need to check if the diaphragm is seated properly, does not have any small tears, etc. Also take a peak at the exhaust valve to make sure it does not have a small piece of sand, grit, salt crystal, etc. preventing it from sealing completely.

To completely isolate an apparent "leaky" 2nd stage, I remove from the hose, and repeat the test (blocking the now-open fitting where the hose was attached with my thumb).

Best wishes.

 

[reefvagabond]

Just wanted to say thanks to everyone for their help. It turns out I was worried for nothing; I was just trying to suck an egg through a straw as lead said. Cleaning out the 2nd stage and putting the diaphragm back is not hard at all, I was just a bit worried having never done it before.

Took my regs on 3 dives today, one to 130 feet and they breathed just fine, nice and dry. Thanks again!