Mouthpieces coming off

[2airishuman]

I've been having a problem with mouthpieces coming off during dives.

It's happened twice, both times with Aqua-Lung metal 2nd stages -- the ones that were sold as part of Conshelf, Calypso, and many other regulator sets in the 70s and 80s. One of the things I've noticed, as I have a large number of them, is that there are two patterns for the outlet. One has a sort of a flare at the end, and the other has a ring closer to the box. The flare ones don't seem as secure, and those are the ones where the mouthpieces are coming off. The ring design seems to appear on earlier production.

I'm using modern mouthpieces that are sold under many brands, and a lay-flat style zip tie. The tie is as tight as possible without exceeding the strength of the lock mechanism in the zip tie.

In one case I was using an elastic neckband that was slightly too tight, which may have contributed to the problem. The other case had no neckband.

Any suggestions?

 

[Scared Silly]

My only thought would be to put some stair tread tape on the mouth piece as that will give it some roughness for the mouthpiece to bite into.

 

[KeithG]

i claim your zip tie is not tight enough.

this is a simple and reliable mechanical design. The zip tie is located inboard of the flair and then tightened to be smaller than the flair. This means the zip tie cannot come off. Since the zip tie is embedded in the channel on the the mouth piece, the mouthpiece also can not come off.

are you using a zip tie gun (or similar replacement device)? hand tight will not be tight enough

 

[USdiver1]

What giffenk said.

 

[Lorenzoid]

This seems like a good place to ask: Can someone point me to a zip tie gun that works well for this purpose? I see them at Home Depot, Lowes, Harbor Freight, etc., but I'm not sure if one is better suited for this use than another.

 

[tbone1004]

This is not a zip tie problem, you are using a mouthpiece that is too big for your regulator.

The "standard" size used by Hollis/Hog/DiveRite/new Aqualung, new Scubapro etc etc are 1 3/16x5/8". The conshelf regs are 1 1/8x1/2". The mouthpiece you are using is sized for the larger regulator orifice, not the old "standard" size. If the mouthpiece goes on and off easily without the zip tie, then it is the wrong size. Mouthpieces that are sized appropriately do not "need" a zip tie, it just makes it better.

Unfortunately the only modern regs using that old size are SEAC and Tusa. All of the "modern" regs, Atomic, Aqualung/Apeks, Dive Rite, Hog/Edge, Genesis, Mares, Oceanic/Hollis/Aeria, Scubapro, new Sherwood, XS Scuba are all using the bigger orifice size. Try a SEAC or Tusa dealer for their mouthpieces which should fit properly.

 

[kelemvor]

whoops I didn't see tbone1004's post until I posted a response. I think he nailed it.

 

[2airishuman]

Thanks so much for the replies.

I've replaced the "flat" style zip ties, for now, which were as tight as they can be before they would start to slip backwards through the ratchet mechanism. The standard ones are stronger, and those seem to work better.

@tbone1004, thanks for the insight on sizes. I'll find some mouthpieces that fit. They do fit loosely without the zip tie. I had no idea there was more than one size. Andy Tanenbaum once wrote, "The nice thing about standards is that you have so many to choose from," and I guess that applies here.

 

[Bob DBF]

i claim your zip tie is not tight enough.

this is a simple and reliable mechanical design. The zip tie is located inboard of the flair and then tightened to be smaller than the flair. This means the zip tie cannot come off. Since the zip tie is embedded in the channel on the the mouth piece, the mouthpiece also can not come off.

are you using a zip tie gun (or similar replacement device)? hand tight will not be tight enough

I always use pliers to tighten zip ties as I just now heard of a zip tie gun. This method has worked for as long as I've been using zip ties.


Bob

 

[2airishuman]

I use either pliers or my fingers. Zip tie guns have their place. They do not necessarily get the zip tie tighter but (the good ones at least) are like a torque wrench, where the tie is tightened to a particular, calibrated level of snugness. Some also cut automatically, saving a step.