2nd Stage Swivel Failures for Sidemount/Independent Cylinders

[jtsfour]

So I have been rethinking my sidemount regulator setup.

When diving a few weeks ago I had the swivel on my long hose come partially apart and extrude its O-ring when I was dressing my tank. I was looking at the swivel last night and realized that it is entirely held together by a single screw in the center.

(As a disclaimer this particular swivel is 2 years old but only has 30 or so dives on it.)

I looked up the type of swivel it was I was surprised to find that it actually seemed to be a cheap swivel. https://www.amazon.com/Degree-Swivel-Adapter-Connector-Scuba/dp/B00376VIZU I bought it when I was setting up my sidemount regs originally (From a shop not amazon). No idea it was so cheap...

Sure enough I found an ancient thread here on SB about what appears to be similar ball swivel failures. ball swivel question

Thinking about this setup this seems to be a significant failure point. The gap in the swivel is so gaping that I am not sure feathering would be possible due to the size. I am not sure any gas would make it to the second stage. Does anyone know if this is the case? I'm not a regulator expert by any means.

What are others opinions and experiences with swivels while dealing with independent cylinders? It seems to me that the swivel failing could cause you to lose all access to gas on one tank. What do you guys use?

I could just keep using the same swivels but check bolt tightness as part of pre-dive.

After this I will probably lose the swivel on the short hose and use a 90 degree angle.

However, a swivel seems to make long hose donations easier on the receiving diver. Does anyone recommend swivels that are designed better?

 

[grantctobin]

So I have been rethinking my sidemount regulator setup.

When diving a few weeks ago I had the swivel on my long hose come partially apart and extrude its O-ring when I was dressing my tank. I was looking at the swivel last night and realized that it is entirely held together by a single screw in the center.

(As a disclaimer this particular swivel is 2 years old but only has 30 or so dives on it.)

I looked up the type of swivel it was I was surprised to find that it actually seemed to be a cheap swivel. https://www.amazon.com/Degree-Swivel-Adapter-Connector-Scuba/dp/B00376VIZU I bought it when I was setting up my sidemount regs originally (From a shop not amazon). No idea it was so cheap...

Sure enough I found an ancient thread here on SB about what appears to be similar ball swivel failures. ball swivel question

Thinking about this setup this seems to be a significant failure point. The gap in the swivel is so gaping that I am not sure feathering would be possible due to the size. I am not sure any gas would make it to the second stage. Does anyone know if this is the case? I'm not a regulator expert by any means.

What are others opinions and experiences with swivels while dealing with independent cylinders? It seems to me that the swivel failing could cause you to lose all access to gas on one tank. What do you guys use?

I could just keep using the same swivels but check bolt tightness as part of pre-dive.

After this I will probably lose the swivel on the short hose and use a 90 degree angle.

However, a swivel seems to make long hose donations easier on the receiving diver. Does anyone recommend swivels that are designed better?

I’m generally opposed to their use. Edd seems to observe way lower failure rates on the Cave Adventurers ones than I do. The Omni-Swivel 2 is an improvement, but on the whole kind of unnecessary. I’ve had a couple blow up underwater.

No need for one on long hose, though there are static 110/70° elbows. Short hose on a fixed 90° on bungee necklace.

 

[Marie13]

I only use the 90 degree fixed ones. Never had an issue.

 

[lostsheep]

90 degree static elbow for me.

I believe any dynamic seal will be less reliable than a static seal. Is it reliable enough? Only you can decide that for yourself.

 

[tbone1004]

I have seen some of the elbows actually strip the threads and blow out before which is cute.

Anyway, the way to prevent that, and it is in the service manuals for these things, is to use a drop of blue loctite on the screw that holds the two halves together. No issues if you follow their service procedures. Some of them do not have loctite on them from the factory, but they very much benefit from it.

 

[jtsfour]

I have seen some of the elbows actually strip the threads and blow out before which is cute.

Anyway, the way to prevent that, and it is in the service manuals for these things, is to use a drop of blue loctite on the screw that holds the two halves together. No issues if you follow their service procedures. Some of them do not have loctite on them from the factory, but they very much benefit from it.

What brand swivel are you referencing? The little service manual that came with mine doesn't mention loctite.

How the hell did an elbow fitting fail structurally? Was it related to high pressures in the LP hose? How?

 

[tbone1004]

What brand swivel are you referencing? The little service manual that came with mine doesn't mention loctite.

How the hell did an elbow fitting fail structurally? Was it related to high pressures in the LP hose? How?

the omniswivel branded ones as well as the ones that Edd sell both mention it. One drop of blue loctite, you won't regret it

The threads that hold the swivel part of the regulator side are very fragile, usually due to cheap metal being used. If you overtighten them a hair too much, any sort of jarring can cause thread failure.

 

[jtsfour]

the omniswivel branded ones as well as the ones that Edd sell both mention it. One drop of blue loctite, you won't regret it

The threads that hold the swivel part of the regulator side are very fragile, usually due to cheap metal being used. If you overtighten them a hair too much, any sort of jarring can cause thread failure.

You mean the threads on the elbow fitting not the threads on the regulator correct?

 

[tbone1004]

You mean the threads on the elbow fitting not the threads on the regulator correct?

yes, the elbows are made in 3 parts. The main body screws into the hose, then the regulator side is 2 pieces. The piece that swivels is retained into the body by a hollow screw with the o-rings on it to seal against the inside of the second stage barrel. That screw is easily damaged if you over tighten it.

 

[jtsfour]

yes, the elbows are made in 3 parts. The main body screws into the hose, then the regulator side is 2 pieces. The piece that swivels is retained into the body by a hollow screw with the o-rings on it to seal against the inside of the second stage barrel. That screw is easily damaged if you over tighten it.

Thanks for the clarification.