DIN O-ring - can't live with it, can't live without it!

[looka]

So, a couple of months ago, my DIN O-ring popped while diving (previous post here).

I discusses the issue with my friend and equipment expert Danny, he reckons that tightening the reg on the valve a bit more, will reduce the gap and dramatically reduce the chance of the O-ring popping again. So I started tightening them much more, to the point they are hard to unscrew at the end of the dive. (if, in sidemount, I had to swap them underwater, it would be EXTREMELY difficult).

The other day, during my safety stop, I did my valve drill, shut my left post, breathed it dry (depressurized). When i opened it again, it wasn't sealing, quite a bit of air was coming out. I shut it again, opened it again and this time it sealed. I did NOT like that.

My question is: is it just my reg? is it supposed to be that difficult? I never had a regulator issue in 18 years of recreational diving qith Yoke valves, now that I have my own tech gear and take care of it religiosly, I have so many issues. What am I doing wrong?

Please share your thoughts.

Luca

 

[PfcAJ]

When you do the valve drill, its conceivable for your reg to become unseated, esp if there is any rotational pressure places on the reg from your hoses.

You shouldn't have to tighten the regs a bunch to get 'em to seal. Are you sure you're using the correct orings?

 

[looka]

You shouldn't have to tighten the regs a bunch to get 'em to seal. Are you sure you're using the correct orings?

i don't need to tighten them a lot to seal, but once it popped. So I am tightening them to prevent them from popping. They seal even if I screw them in softely, but the "gap" the O-ring would have to fill is bigger. So I am not sure what is best.

Is the un-seated reg during a valce-drill dangerous, you think?

 

[PfcAJ]

O rings fail from time to time. If it happens to you frequently, I'd look into it VERY carefully. Once is a 'fluke event' imo, and not worth worrying about.

If it unseats, just fix it. Ive had stage/deco regs unseat and leak a little more times than I can count. No biggie

 

[looka]

O rings fail from time to time. If it happens to you frequently, I'd look into it VERY carefully. Once is a 'fluke event' imo, and not worth worrying about.

If it unseats, just fix it. Ive had stage/deco regs unseat and leak a little more times than I can count. No biggie

Thanks

 

[Golo]

I'm no expert in regs, but I know a thing or two about O-Rings. Not exactly sure what you mean by an O-Ring "popped", do you mean it broke? Or did it get out of the groove but stayed intact? When I look at my reg, I can't really figure out where it would go (unless it breaks), though my reg might be designed slightly different?

Anyways, with O-Rings, you can theoretically have a blow-by event if you have a sudden high pressure hit, though if your O-Ring is in good condition and is properly sized (squeezed), I don't think that should be a problem. Did you try to turn on the air gently and abruptly, to see if that makes a difference?

Now, if the O-Ring is for some reason too small (or the groove of your reg is too deep for the O-Ring), so it doesn't get squeezed properly, then it's a bit different. Also, as the O-Ring ages, even if it looks perfectly fine the squeeze gets less and less, which could eventually also lead to a leak. The aged rubber might not be able to react as quickly to sudden pressure changes.

If you got dirt on your O-Ring or if imperfections in the sealing surfaces are too big (which I doubt), that could lead to a leak as well, but I am sure you know all that already.

The pressures used in Scuba are actually rather high for just an O-Ring, and exposure to salt water, plus scratching the surface when screwing in and out all the time means they age rather quickly.

By the way, you also don't want an O-Ring that is too big, as installation might then damage either O-Ring or worse, the metal part.

 

[macado]

What kind of first stages do you have? I usually have far less issues with DIN o-rings than I do yoke and have seen many more failures of yoke o-rings than I have DIN but that may just be anecdotal based on my own personal obersvations.

I know this may be slightly off topic but Apeks uses smaller size o-rings than traditional DIN o-rings.

E.G. I believe Apeks uses -111 where standard DIN o-ring is usually -112. This might be something to consider.

 

[looka]

What kind of first stages do you have? I usually have far less issues with DIN o-rings than I do yoke and have seen many more failures of yoke o-rings than I have DIN but that may just be anecdotal based on my own personal obersvations.

I know this may be slightly off topic but Apeks uses smaller size o-rings than traditional DIN o-rings.

E.G. I believe Apeks uses -111 where standard DIN o-ring is usually -112. This might be something to consider.

I am using Apeks and you might be right. Thanks

 

[Mr Carcharodon]

Try using a harder rubber. Viton in 90 durometer will be more extrusion resistant than 70 durometer. The softer rubbers are commonly used in the low pressure parts of regulators and harder in the high pressure parts. Also do get o-rings made of a known material. Some o-rings that are intented for low pressure applications like plumbing will not be reliable at high pressure.

 

[looka]

Try using a harder rubber. Viton in 90 durometer will be more extrusion resistant than 70 durometer. The softer rubbers are commonly used in the low pressure parts of regulators and harder in the high pressure parts. Also do get o-rings made of a known material. Some o-rings that are intented for low pressure applications like plumbing will not be reliable at high pressure.

Interesting. Where do you buy your O-rings? and get all the specs? I normally get them in a dive shop or online, never had access to all the data!