O-ring expansion?

robinfante · 10th October 2007, 15:24

I seem to be having a bit of a problem with O-ring deformation in my Meg. I noticed the other day that the o-ring where the inhalation hose leaves the head had expanded, enough that I had to change it out to assemble the unit. The other one looked fine. I'm also having the same problem with one of the orings on my cis canister. Normally I associate this kind of thing with media contamination (I manufacture hydraulic/pneumatic cylinders for a living), but there is no evidence of that. Has any one else experienced this? Any idea why? I never saw it on my prism or kiss units after roughly 130 on each (the Meg has about 100). Both distorted orings appear to be of the same material, even though they are different manufacturers - some sort of orange low-durometer rubber, nitrile perhaps?

I also was wondering if anyone knew the correct sizes for the cis canister o-rings. Its easy enough for me to get replacements from my seal suppliers, but now that the one has expanded I don't want to mis-spec it.

tia
rob infante

York · 10th October 2007, 16:20

Rob,
check out http://www.rebreatherworld.com/megal...tml#post136495

There was some discussion as to the material. I presume you are asking for the specs of the 2 locking-plate O-rings?

J

robinfante · 10th October 2007, 16:35

yes exactly. The outer o-ring on the top piece of the cis canister is the one that expanded. The inner one has not so far.

The 3 little jobs for the screws are fine. Speaking of which, if anyone has found a source for them I'd like to get spares too, before I snap one.

USSMEG · 10th October 2007, 18:17

Quote: (Originally Posted by robinfante)

yes exactly. The outer o-ring on the top piece of the cis canister is the one that expanded. The inner one has not so far.

The 3 little jobs for the screws are fine. Speaking of which, if anyone has found a source for them I'd like to get spares too, before I snap one.

I have the sizes at home, And see below.

I picked up one of these cones (to measure the O-rings) 9440K41 from http://www.mcmaster.com/
years ago after having used one @ work, Its the best $20.00 you'll ever spend. I've now given a couple to friends at X-Mas. And they Love em.
Later
Paul

we should come up with a contest and give a few of these away, I'll work on it at the party...

USSMEG · 10th October 2007, 23:10

Quote: (Originally Posted by USSMEG)

I have the sizes at home, And see below.

I picked up one of these cones (to measure the O-rings) 9440K41 from http://www.mcmaster.com/
years ago after having used one @ work, Its the best $20.00 you'll ever spend. I've now given a couple to friends at X-Mas. And they Love em.
Later
Paul

we should come up with a contest and give a few of these away, I'll work on it at the party...

Outside one is 2-245 Silicone 65D
Inside one is 2-228 Silicone 65D
and the screws 2-202 and you need 6 of these Buna 70D

Paul

robinfante · 11th October 2007, 19:25

perfect. thanks so much

JCdesign97 · 11th October 2007, 20:22

Interesting - I just noticed this thread and I have had the mysterious expanding o-ring issue going on now for a while now myself. It only happens on the OMS 1st stage DIN fitting on my argon bottle, though, so I never really made a big deal about it. Every time I take the reg off the bottle to fill it the o-ring pops out and when I try to stuff it back in it's easily 1.3 times it's original size. I have a baggy full of the brown (Viton?) ones so I haven't switched to a buna, but it never happens on any of my other 1st stages. I just assumed that maybe it was some reaction with the argon, but I gave up trying to figure it out some time ago ...

brandonmc · 11th October 2007, 21:04

Reactions with Argon... now Ive heard it all

JCdesign97 · 11th October 2007, 21:20

Quote: (Originally Posted by brandonmc)

Reactions with Argon... now Ive heard it all

Oh, it's like that eh McJangles?? Hey, you never know - maybe you should switch your thesis to that, since ...

10th October 2007, 15:24	#1 (permalink)
robinfante I have a smoking gun Current Rebreather/s: Megalodon Prism Topaz MK 15.X Other Rebreather/s: Sport Kiss Join Date: Nov 2005 Location: mountain lakes nj Posts: 133	O-ring expansion? I seem to be having a bit of a problem with O-ring deformation in my Meg. I noticed the other day that the o-ring where the inhalation hose leaves the head had expanded, enough that I had to change it out to assemble the unit. The other one looked fine. I'm also having the same problem with one of the orings on my cis canister. Normally I associate this kind of thing with media contamination (I manufacture hydraulic/pneumatic cylinders for a living), but there is no evidence of that. Has any one else experienced this? Any idea why? I never saw it on my prism or kiss units after roughly 130 on each (the Meg has about 100). Both distorted orings appear to be of the same material, even though they are different manufacturers - some sort of orange low-durometer rubber, nitrile perhaps? I also was wondering if anyone knew the correct sizes for the cis canister o-rings. Its easy enough for me to get replacements from my seal suppliers, but now that the one has expanded I don't want to mis-spec it. tia rob infante __________________ Homer to Bart: “When a woman says nothing’s wrong, everything is wrong. And when a woman says everything’s wrong, EVERYTHING is wrong. And when a woman says something’s not funny, you better not laugh your ass off!” Check out www.robinfante.blogspot.com for trip reports and pics.
(Online)

10th October 2007, 16:20	#2 (permalink)
York probubbly not Current Rebreather/s: Megalodon Other Rebreather/s: Join Date: Mar 2005 Location: Bristol, UK Posts: 118	Re: O-ring expansion? Rob, check out http://www.rebreatherworld.com/megal...tml#post136495 There was some discussion as to the material. I presume you are asking for the specs of the 2 locking-plate O-rings? J
(Offline)

10th October 2007, 16:35	#3 (permalink)
robinfante I have a smoking gun Current Rebreather/s: Megalodon Prism Topaz MK 15.X Other Rebreather/s: Sport Kiss Join Date: Nov 2005 Location: mountain lakes nj Posts: 133	Re: O-ring expansion? yes exactly. The outer o-ring on the top piece of the cis canister is the one that expanded. The inner one has not so far. The 3 little jobs for the screws are fine. Speaking of which, if anyone has found a source for them I'd like to get spares too, before I snap one. __________________ Homer to Bart: “When a woman says nothing’s wrong, everything is wrong. And when a woman says everything’s wrong, EVERYTHING is wrong. And when a woman says something’s not funny, you better not laugh your ass off!” Check out www.robinfante.blogspot.com for trip reports and pics.
(Online)

10th October 2007, 18:17	#4 (permalink)
USSMEG USSMEG Current Rebreather/s: Megalodon Other Rebreather/s: Join Date: Mar 2005 Location: Mass Posts: 271	Re: O-ring expansion? Quote: (Originally Posted by robinfante) yes exactly. The outer o-ring on the top piece of the cis canister is the one that expanded. The inner one has not so far. The 3 little jobs for the screws are fine. Speaking of which, if anyone has found a source for them I'd like to get spares too, before I snap one. I have the sizes at home, And see below. I picked up one of these cones (to measure the O-rings) 9440K41 from http://www.mcmaster.com/ years ago after having used one @ work, Its the best $20.00 you'll ever spend. I've now given a couple to friends at X-Mas. And they Love em. Later Paul we should come up with a contest and give a few of these away, I'll work on it at the party...
(Online)

10th October 2007, 23:10	#5 (permalink)
USSMEG USSMEG Current Rebreather/s: Megalodon Other Rebreather/s: Join Date: Mar 2005 Location: Mass Posts: 271	Re: O-ring expansion? Quote: (Originally Posted by USSMEG) I have the sizes at home, And see below. I picked up one of these cones (to measure the O-rings) 9440K41 from http://www.mcmaster.com/ years ago after having used one @ work, Its the best $20.00 you'll ever spend. I've now given a couple to friends at X-Mas. And they Love em. Later Paul we should come up with a contest and give a few of these away, I'll work on it at the party... Outside one is 2-245 Silicone 65D Inside one is 2-228 Silicone 65D and the screws 2-202 and you need 6 of these Buna 70D Paul
(Online)

11th October 2007, 19:25	#6 (permalink)
robinfante I have a smoking gun Current Rebreather/s: Megalodon Prism Topaz MK 15.X Other Rebreather/s: Sport Kiss Join Date: Nov 2005 Location: mountain lakes nj Posts: 133	Re: O-ring expansion? perfect. thanks so much __________________ Homer to Bart: “When a woman says nothing’s wrong, everything is wrong. And when a woman says everything’s wrong, EVERYTHING is wrong. And when a woman says something’s not funny, you better not laugh your ass off!” Check out www.robinfante.blogspot.com for trip reports and pics.
(Online)

11th October 2007, 20:22	#7 (permalink)
JCdesign97 My unit can beat up yours Current Rebreather/s: Optima Other Rebreather/s: Join Date: Mar 2007 Location: PA, USA Posts: 350	Re: O-ring expansion? Interesting - I just noticed this thread and I have had the mysterious expanding o-ring issue going on now for a while now myself. It only happens on the OMS 1st stage DIN fitting on my argon bottle, though, so I never really made a big deal about it. Every time I take the reg off the bottle to fill it the o-ring pops out and when I try to stuff it back in it's easily 1.3 times it's original size. I have a baggy full of the brown (Viton?) ones so I haven't switched to a buna, but it never happens on any of my other 1st stages. I just assumed that maybe it was some reaction with the argon, but I gave up trying to figure it out some time ago ... __________________ Cheers, John
(Offline)

11th October 2007, 21:04	#8 (permalink)
brandonmc New Member Current Rebreather/s: Megalodon Other Rebreather/s: Join Date: Oct 2006 Location: Philadelphia Posts: 76	Re: O-ring expansion? Reactions with Argon... now Ive heard it all __________________ http://mcjangles.blogspot.com/
(Offline)

11th October 2007, 21:20	#9 (permalink)
JCdesign97 My unit can beat up yours Current Rebreather/s: Optima Other Rebreather/s: Join Date: Mar 2007 Location: PA, USA Posts: 350	Re: O-ring expansion? Quote: (Originally Posted by brandonmc) Reactions with Argon... now Ive heard it all Oh, it's like that eh McJangles?? Hey, you never know - maybe you should switch your thesis to that, since ... __________________ Cheers, John
(Offline)

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