[Mr. Stealthy]

I was considering using some HNBR O-rings on some of the dynamic o-rings (ram, poppit, lpr/hpr pistons, bolt O-rings). The Durometer and sizes would be the same. Has anyone tried this or think I may have any issues? I have experimented with O-rings in the past with good results on spool valve guns and played around a little bit with O-rings on the bolt of my G6R as well. They are not much of a difference in cost and I figure they should last a bit longer than Buna.

[blueshifty]

HNBR is mostly used for environmental resistance. Viton and urethane are the only 2 materials with better abrasion, compression set and running friction properties than buna. I wrote a long essay about it in the MacDev oring thread.

[Mr. Stealthy]

Originally Posted by blueshifty

HNBR is mostly used for environmental resistance. Viton and urethane are the only 2 materials with better abrasion, compression set and running friction properties than buna. I wrote a long essay about it in the MacDev oring thread.

I will reference your essay then. I was uncomfortable using Viton in any of the internals due to the higher durometer and I am not really able to track down urethane in some of the sizes I need in 70 durometer. So essentially they will work fine but the only benefit would be some environmental resistance? Even if that is the case, this would still be benefitial in areas like the ram and bolt for me. I was also curious if they would swell like Buna O-rings do with Dow-55. Thanks!

[blueshifty]

Higher durometer usually just means a higher breakaway friction, but lower running friction. The harder material creates a tighter seal. 75 viton is still fine for most paintball applications.

[Mr. Stealthy]

Originally Posted by blueshifty

Higher durometer usually just means a higher breakaway friction, but lower running friction. The harder material creates a tighter seal. 75 viton is still fine for most paintball applications.

Thanks for your help.

[Cocker_Madness]

i use viton x-rings on the rammer, they work fine...

[Mr. Stealthy]

Originally Posted by Cocker_Madness

i use viton x-rings on the rammer, they work fine...

Thanks I may try some!