Are viton o-rings really necessary?

[redacted]

I have little experience with BDs. On my balanced pistons and balanced barrel poppet 2nds, I load up the dynamic o-rings with lube. Those that use a double o-ring design (a sealing ring and a scraper ring) seem to have little problem holding lube between the rings. Even the single ring piston heads don't seem to have any problem with a proper lube lasting many years. The HP piston o-ring may have some problem, but it resonates and lets you know if it is time to re-lube. Scubapro Mk10s seem to be a bit more problematic in this area than the Mk5 or Mk20 designs.

Sorry we can't continue. Unfortunately, it time to go diving for a few days.

 

[halocline]

I find it VERY comical that the same people proposing to stretch service life also propose to use the regulator design that most needs the service. The lubercation on pneumatic piston seals only lasts so long, when its gone, you have issues.

When you made this comment, to whom were your referring as "the same people", and what regulator design needs the most service?

 

[fppf]

Dive Safe.

I have no experience with SP regs, as I said. Just used the design base as an example.

Wipers will help the issue, but you also need to be careful of over lubrication. To much lube and it collects dirt and becomes rubbing compound. This is not as much of an issue in the case we are discussing because the area should only seen clean breathable gas. But in a second stage that gets flooded in areas when its out of the mouth attention needs to be paid.

 

[fppf]

When you made this comment, to whom were your referring as "the same people", and what regulator design needs the most service?

"the same people" was referred to those that contest yearly service is over kill and like to stretch there service intervals.

IMO piston regulators tend to need service sooner, which is the design most guys are using in these talks. The dynamic piston seals for the sensing element is a wear point that a diaphragm regulator just does not have. If its a flow through design there is also a dynamic seal that separates the HP from the IP side. If the piston design is not a sealed design then you have water entering the reference chamber that can introduce debris into the dynamic seals. The diaphragms have a leg up there because the diaphragm is not a sliding seal, it flexes. So if water is let into the reference chamber its not that big of an issue. And most diaphragm designs seal the reference chamber and use another transfer pin assembly.

 

[halocline]

So lets continue the education

Now, even more important is that the seal stresses on THIS dynamic piston seal are going to be MUCH higher then the dynamic piston seal your thinking of, the one that senses on a "Piston Regulator". This is because the pressure delta with a full cylinder is very high, the inside of the balance chamber is at the IP pressure and the pressure around the "HP Valve" is cylinder pressure. Making a pressure delta of over 3,000 PSI at times. Where in a standard "Piston Regulator" the pressure delta is very low (in relative terms) at IP pressure vs ambient.

This is also why I did not want to go into the failure analysis, its very technical and most don't understand it anyway and get confused.

Sorry, you're wrong, but you're doing fine keeping up the arrogance.

The pressure gradient on a diaphragm reg balance chamber o-ring is lower than on a BP HP o-ring seal. On the diaphragm balance chamber, one side is supply, the other is IP. On a piston reg, one side is HP, the other is ambient.

The only way friction in the balance chamber o-ring could freeze up the HP seat (which is the "piston" you keep talking about) would be if you used glue for lubricant. Maybe there was something wrong with the spring in your reg, maybe something blocked the seat/orifice sealing surface, who knows. Maybe the pin from the main diaphragm got dislodged and kept the seat from seating properly. But your explanation is just not accurate.

Imagine if it were true that poor lubrication at the balance chamber o-ring could cause HP seat failure. Do you really think someone would design something in such a faulty manner, and that it would be then successfully used on millions of dives for decades? Do you think that your reg was the only one to have old lube or no lube in that o-ring?

 

[fppf]

Are you really reading everything?
In the section you quoted I think I was clearly comparing a dynamic seal with high pressure across it and a dynamic seal between IP and ambient. That is why I said

"Now, even more important is that the seal stresses on THIS dynamic piston seal are going to be MUCH higher then the dynamic piston seal your thinking of, the one that senses on a "Piston Regulator"."

Please note I referenced the SENSE piston, meaning the large round thing between IP and ambient.

I take it you now understand that there is a dynamic piston seal even in a "balanced diaphragm" regulator because your not bringing that up anymore.

And if we are calling names, I would much rather be arrogant then ignorant.
You clearly don't understand seal design and failure modes, and that's ok. Its a very complex subject not to be taken lightly. Just take the little baggy of parts and install them per the service manual and all will be fine.

 

[fppf]

Maybe we should have a Mod split this thread, we dragged it WAY off topic from the OP question.

 

[rhino3201]

WOW did this discussion take a turn since I posted. Did everyone read the part where I said "DUMB LUCK"? Or maybe just good equipment. I keep my equipment well cleaned after every dive and store it properly. I also only average about 10 dives a year. Maybe that has a little to do with it. The implication that some of us are too stupid to know when to service or gear is a little agrivating. Fact is, I wouldn't recommend ANYONE waiting as long as I have to service their regs. I also regurlary inspect the O rings in my B.C., have extra straps for my mask and fins, and have emergency equipment to help in the event they are needed. I am not a moron, and I am taking my regs to be serviced this week before I start diving this season.

All I wanted to know is the same thing as the origional post, are Viton rings really necessary? Not to be insulted and for everyone to thump their own chest about how smart they are or how stupid everyone else is. Stick to the subject.

 

[aquaregia]

I have another thought. I have no personal experience sky diving but from my understanding is that you are always taught how to pack a parachute because no sane person would trust such an important job to a stranger. Now should not the same thing apply to regulator repair?

That's why I do my own car maintenance too. I let a mechanic replace my rotors once because I was in a time crunch and my power assist hasn't worked right since.

 

[Mike Boswell]

Is there even REALLY a difference between viton o-rings and the generic, your gear will blow up if them come in contact with 02 o-rings? Or is that just yet another way for them to overcharge you for something that's not really necessary?

Looking at them side by side I can't even see a difference. If I was to dump all my BAD o-rings in the pack with the vitons, they'd get mixed up, and I'd have no idea which ones I was using. S**t is there even such a thing as vitons or did they just make up a word and put in on the package. How do do I even know that pack of vitons are even vitons other than just the magic word on the box...considering they look the same as the other ones?

WOW did this discussion take a turn since I posted. Did everyone read the part where I said "DUMB LUCK"? Or maybe just good equipment. I keep my equipment well cleaned after every dive and store it properly. I also only average about 10 dives a year. Maybe that has a little to do with it. The implication that some of us are too stupid to know when to service or gear is a little agrivating. Fact is, I wouldn't recommend ANYONE waiting as long as I have to service their regs. I also regurlary inspect the O rings in my B.C., have extra straps for my mask and fins, and have emergency equipment to help in the event they are needed. I am not a moron, and I am taking my regs to be serviced this week before I start diving this season.

All I wanted to know is the same thing as the origional post, are Viton rings really necessary? Not to be insulted and for everyone to thump their own chest about how smart they are or how stupid everyone else is. Stick to the subject.

Viton has exceptional heat and chemical resistance, and is applicable in Scuba products where higher oxygen levels (e.g. Nitrox) are used.

There is a good discussion of various o-ring materials here: Oxygen Compatible O-Rings, Lubricant and Tools - Dive Gear Express

I'm handy. Been doing maintenance for more than 50 years. I service my own stuff generally - everything you would find in a house or on a ranch -including diesel engines, toilets, trucks, electronics, trailers, electric systems, tractors, pumps, computers, irrigation systems, and so forth.

But I won't service my regulators. Not "can't", "won't". I simply cannot do as good a job as a good professional who services regulators for a living.

Others can do as they wish and more power to them. As long as they are competent, experienced, trained, current, have the tools, receive regular factory updates and service bulletins, have a factory rep to talk to about any problems, and obtain good quality, trustworthy parts, they should be fine.

Me, I let the professionals service my regulators.