O-ring size for M3 power plenum

[Airgunmann]

I'm looking for a viton o-ring to replace pur 90 I made a peek washer for it M3 lists as a 2.84x2.62 pur 90 and I'm having trouble figuring out which is Id and od and what size viton o-ring to get thanks for your help I thought I'd have one in my kits but I don't

 

[cwcarrera]

It is a metric O ring. 2.62mm is the cross section of the O ring and 2.84mm is the ID of the O ring. That O ring crosses over to a -104 in standard AS568 specs. Not sure what benefit you are looking for by going to Viton instead of sticking with the specified Urethane 90 durometer O ring?
Here is a link to the specified O ring...

AS568-104 U90 EU Polyether Urethane 90 Duro O-Ring [U90104] : The O-Ring Store LLC, We make getting O-Rings easy!

The O-Ring Store LLC AS568-104 U90 EU Polyether Urethane 90 Duro O-Ring [U90104] - 1/8"ID X 5/16"OD X 3/32"CS Description: Polyurethane Polyurethane rubber is notable for its combination of hardness with elasticity, outstanding abrasion resistance and tear strength. Elastomeric urethane rubber...

www.theoringstore.com

 

[Airgunmann]

Thanks there is a sticking issue if you leave the gun sit for a while which drops the first couple shots 20 or more fps using a tight tolerance peek washer and a viton o-ring takes care of it

 

[cwcarrera]

Viton is most typically associated with chemical and hydrocarbon resistant applications, I guess I don't see how it will help with your application but I hope I am wrong. Good luck, I hope it works out for you.

 

[Airgunmann]

There was a big post on it it moves easier and doesn't cause the sticking issues that the mk2 with impact and M3 have after sitting several hours which causes 20 or more fps loss in first couple shots but you have to use a peek washer with tight tolerance so it doesn't extrude

 

[cwcarrera]

There was a big post on it it moves easier and doesn't cause the sticking issues that the mk2 with impact and M3 have after sitting several hours which causes 20 or more fps loss in first couple shots but you have to use a peek washer with tight tolerance so it doesn't extrude

Good luck, I hope it all works out for you and your problem is solved.

 

[Airgunmann]

Well I got the correct o-ring which I think it was 104 in viton assembled the 720 with the peek disc and viton o-ring installed the 720 on my mk2 and also installed a brass piston the amp regulator reassembled the mk2 with the upgrades I was able to get the same fps or power level at 10 bar less with the 720 plenum when I was testing it aired it up and left it set for 12 hours took 6 shots slowest fps I got was 8 fps in the first 6 shots every thing is holding air like it should I also all ready added a airmarksman back bone to it a barrel holder and made a shroud which I have tested for clipping and it's good I have to paint it yet so the 720 kit with the M3 springs it came with the M3 valve adjuster to but I'm not using it I installed the new spring and used mk2 valve adjuster because I've read the M3 makes a clicking noise but the M3 valve spring is stronger I noticed that I'll get some picks I have it set at 150 at my huma first reg which I added and 110 at the amp reg adjusted the speed averaging 903 fps with 33.95 jsb mk2 seems to be easier on air but I haven't shot a whole tank through it yet to tell so far I'm happy with the upgrades