PDA

View Full Version : O-rings



seasnake
04-25-2007, 05:55 PM
What's everyone prefer for o-rings? Do I understand correctly that EPDM would be the superior material for o-rings in scuba applications?

Ron

fredob
10-30-2007, 01:16 AM
epdm has always worked for me;)

Sarah
10-30-2007, 02:46 AM
I prefer fluoropolymer elastomers such as Viton.

;)

Papa Bear
10-30-2007, 05:30 AM
I prefer White Gold for my rings!

BamaCaveDiver
10-30-2007, 05:36 PM
The thing to remember is that any oring will burn under the right conditions (same guys who discovered the leaky cylinder that passed hydro got bored one day and put this to the test), so you need to look at what is given off should that happen. Viton is a good choice for oxygen service, but when it burns it does give off some nasty gases. EPDM does not seem to be as bad when it burns.

acelockco
10-30-2007, 10:16 PM
I use the el-cheapo o-rings you can get at the local hardware store. They don't last as long as the other o-rings out there, but they are so cheap that you can replace them on every dive and never even think about it. You can get a 100 pack for just a few bucks.

By the way, they still do last a long while, but I am really careful with my gear.

amtrosie
10-31-2007, 01:13 AM
Ah yes, but the right O-ring is always the answer. The last thing I want is a cheap O-ring ruining a good dive. Or better yet, failing at a critical time of the dive, on a critical piece of gear. That old rule of coming up as many times as one goes down comes into jeapordy. If one is willing to scrimp on something as small and cheap as an o-ring, how much more on something more expensive. God forbid, it is a life sustaining piece of gear.......Oh wait,!!! thats what scuba is all about!!

acelockco
10-31-2007, 01:29 AM
It has never been a problem for me in the past. It is also something most of my dive buddys do. I have only had one o-ring fail on us the entire summer, and it was operator error that caused the problem. It happened before the dive and of course I had plenty of extra.

By the way, do you really think the hardware store o-rings are not as good as the ones from the dive shop? My thought is the "standard" o-rings (like the ones from Trident) that you buy at the dive shop are IDENTICAL to the ones from the hardware store. I bet they are most likely made in the same factory, but have different packaging. Of course as soon as the SCUBA name is added, the price goes up.

Now if you are not using standard o-rings then that is another thing altogether. I still have about 60 dives on the same hardware store o-ring without any problems.

And don't fool yourself, ALL o-rings will fail, even Papa Bear's White Gold ones. It is really not a big deal because the large majority of the time this happens before the dive and is corrected.

amtrosie
10-31-2007, 11:37 PM
It has never been a problem for me in the past. It is also something most of my dive buddys do. I have only had one o-ring fail on us the entire summer, and it was operator error that caused the problem. It happened before the dive and of course I had plenty of extra.



I bet they are most likely made in the same factory, but have different packaging. Of course as soon as the SCUBA name is added, the price goes up.




And don't fool yourself, ALL o-rings will fail, even Papa Bear's White Gold ones. It is really not a big deal because the large majority of the time this happens before the dive and is corrected.


Your argument is that a majority of the time an o-ring will not fail?

I refuse to play the odds (call it the cheap Jew in me), or leave something so easily attended to, to chance!! A simple service call will ward off those failures and virtually guarantee a fail safe-dive. Nothing is 100% (except death and taxes), so let's dispense with everything will fail, eventually argument!


As for the cost esculating when annotated as "For SCUBA use", I have to chuckle. The scuba industry has nothing on the aviation industry when it comes to prices! :eek:

lottie
10-31-2007, 11:54 PM
Your argument is that a majority of the time an o-ring will not fail?

This also depends on whether you're an optimist or a pessimist - is the glass half-full or half-empty?



I refuse to play the odds (call it the cheap Jew in me), or leave something so easily attended to, to chance!!


Wouldn't that be the other way around? The cheaper the better - keep all the money in the pot and count it each night? (i'm thinking scrooge)
So does that mean you have a big nose??? :) ;)

I'm off to eat some latkes...(2 months early!! :D)

acelockco
11-01-2007, 12:12 AM
As for the cost esculating when annotated as "For SCUBA use", I have to chuckle. The scuba industry has nothing on the aviation industry when it comes to prices! :eek:


I know you are dead on with that one!

amtrosie
11-01-2007, 05:03 PM
This also depends on whether you're an optimist or a pessimist - is the glass half-full or half-empty?



Wouldn't that be the other way around? The cheaper the better




Am I pessimist? Nah, you have to think there to be something in the glass to begin with!!! :eek: :eek: I am of the firm belief that there is a hole in the bottom of the glass, and that all the water drained out!

My training and experience within the aircraft industry has taught me to leave nothing to chance. That includes, letting pilots play with buttons in the cockpit, for they ALWAYS BREAK SOMETHING!!!!! leaving me something else to repair. :eek: and I have enough to do without their assistance!!

When one deals with life support equipment, your approach is totally different. It is not IF something will break, but rather WHEN something will break, and it always does!!! So, one must view all mechanical things in that light. My approach then, is to set myself up for the FEWEST failures, and leave as little to chance as possible.


As for being cheap, that is just genetics, and can not be helped. My nose has been rubbed down by the application of said appendage to the grindstone! :rolleyes:

lottie
11-01-2007, 07:10 PM
My nose has been rubbed down by the application of said appendage to the grindstone! :rolleyes:

Oy vey - that must have been painful :)

seasnake
11-07-2007, 07:18 PM
I prefer fluoropolymer elastomers such as Viton.

;)

Although I know viton are supposed to be more durable, my understanding is they are a bit of overkill for scuba, especially if you service your gear regularly. And then there is the point brought up by Bama that they get kinda toxic when they go poof.

Amtrosie, isn't it true that viton is not the common material for o-rings in aircraft applications, even in the presence of 100% O2? I thought I read that it is more common to see EPDM?