Second stage design

[James-S]

Hi everyone. I am possibly thinking of buying another regulator for a pony/stage, and I would like to know if people think that you need to have a second stage with a front face plate that you can remove without tools so that you can clean it underwater or not. The reg could also possibly be used at some point as my primary, so this refers to having a removable face plate on a regulator for any purpose.

My thinking is that it would make sense for you to be able to clean it underwater, but so many regulators now, like most of the scubapros, don't have a second stage that you can take apart without a screwdriver, so if manufacturers aren't making them, then does that mean that there isn't the demand for them? On the other hand, how would a second stage actually get blocked to the point of malfunction? the diaphragm is held in place by the face plate or something else, so how could silt of whatever get in there and dislodge it?

Thanks for any replies

 

[LeadTurn_SD]

Disclaimer: I'm not a cave/wreck diver, and I do not dive in a high-silt environment, so take everything I say with a grain of "silt"

The reasoning behind being able to remove the front cover on a 2nd stage underwater is to clear sand, silt, debris that may have entered and fouled the 2nd stage (probably due to being dragged in silt, mud, sand, etc.). Silt/sand can foul the exhaust valve, diaphragm..... This would most likely be the regulator on a stage bottle or pony, not the one in your mouth (hopefully you are not dragging your face through silt ).

So, the questions you'd need to answer regarding your own diving:

1. Do you dive in environments where dragging the pony's 2nd stage through silt and sand is possible?

2. If it is a pony regulator you are concerned about.... would you only discover the 2nd stage was "fouled" when you needed it? A pony is considered a "bail-out" bottle; if you discover the 2nd stage on the pony is "fouled" with silt/sand when you need it, well, how will you fix it? What will you be breathing while you take it apart?

3. Do you know how to remove & replace the purge cover and diaphragm on a 2nd stage? It is easy (on the surface), but you do need two hands, need to handle the diaphragm carefully, and need to seat it correctly.... you would not want to practice this the very first time underwater.

So, for non-technical diving, my opinion is that it is not an issue if your 2nd stages can't be easily taken apart underwater.

Best wishes.

 

[halocline]

All of my 2nd stages are scubapro, and many of them can be taken apart without tools; the exceptions are the old 109 metal case regs. But G250s, D400s, and R190s all have faceplates (or in the D series, a soft rubber case) that can be removed. The G250s and R190s have a little plastic pin that you'd have to remove with a knife or your fingernail, but you don't even need that pin; you can leave it out and just tighten the faceplate hand tight.

Debris can get in the 2nd stage under the diaphragm via the mouthpiece, although you could easily just leave a plug in it. On the outside of the diaphragm it could accumulate through the vent holes in the cover, and I suppose if enough got in there it could prevent the diaphragm from fully closing the valve. I've never understood the real-world necessity of disassembling and cleaning a 2nd stage underwater, but I suppose it could happen. I'm sure it's extremely rare, though. I would not worry too much about it, but if you are, just get a R190; cheap and reliable, and then you can take it apart if you ever find yourself in need.

 

[James-S]

Thanks for the replies guys. Out of interest, has anyone ever actually had to clean out a second stage underwater? I don't mean chose to because the breathe was a bit wet, but actually had to in order to get anything out of the reg?

 

[LeadTurn_SD]

Some of the cave divers on this board have reported that they needed to. I believe it was on stage bottles that they had "dropped" on the cave floor, came back to on their exit, and found sand/silt had been swept into the mouthpieces and fouled the 2nd stage.... in those types of envirnoments, it would certainly be prudent to have a 2nd stage with an easy-to-remove cover.

For recreational dives, I don't see the necessity.

Best wishes.

 

[herman]

I agree with the rest, it's rare you need to open a second stage, esp underwater. For pony bottles, just use a mouthpiece plug or one of the octo holders that cover the mouthpiece.

 

[knowone]

There is a second stage pouch available that incorporates with the sling or if a pony the oft mentioned around the neck or clipped to a shoulder where they should be safe unless as already mentioned you are mining.

 

[maxguru]

I had to clean one out once when I puked into it. Green pepper was keeping the exhaust port open, making the reg breathe wet.

Max
DSAT 198186

 

[ianr33]

Only ever taken a reg apart once underwater,failed to fix it!

I dont see any reason to have a reg that requires tools to take the faceplate off. What possible advantage could that have? KISS