Green vs black o rings. Is there a difference?

[ImpactX]

Anyone who owns one of the big tuxing gold filter knows they come with the green o rings instead of black. Sometimes when filling up your tanks, the green o ring would get squeeze out from the gap. Even when it doesnt, you open the cap and the o ring is like flaking off or shedding its skins like a snake. It would get crusty and break up and not rubbery like the black o ring. 

Is there a difference between the green o rings vs black o rings. Is there a reason why tuxing is using the green o rings? I am thinking of ordering some black one same size to replace. Would that be a good idea or not? Why would they use these type of green o rings when it see so bad.

 

[Peashooter]

I am not sure about the colored ones, but O-rings do come in a few different materials, such as nitrile ( NBR ) - butane ( IIR ) - Ethylene ( EPR ) - Ethylene propylene (EPDM ) - Silicone, and so on.

I found a short what is what on O-ring materials. https://www.thomasnet.com/articles/hardware/o-rings-material-makeup/

 

[dizzums]

i think green is generally rated for 'air use' but that isnt really hpa, more like refridgerant lol .. i think mainly we need to worry about the hardness ..not to hard or theyll chip ...

 

[Camaro454]

O ring colour/O ring material 

Black/FFKM, NBR, EPDM, Viton, Alfas, Neoprene 

Green/HNBR, HSN, Viton 

Blue/Fluorosilicone 

High Visibility Green/NBR 

Brown/Viton 

Red/Silicone, PFAS, TES 

Clear/Urethane 

White/NBR, Viton, Silicone, EPDM, PTFE 

Yellow/NBR 

Each o ring material offers various properties, making them suitable for different applications and processes. It is important to opt for the most suitable material to provide the best seal for your application. 

If I was to guess, I would say Tuxing used viton orings for these static seals. Because of the pressure and temp. 90 durometer would be my guess.

 

[nervoustrig]

Color does not provide a 100% iron-clad guarantee to ID the material but most likely the green is hydrogenated buna nitrile (HNBR), which is a more durable compounding of the more typical "plain" black Buna-N (NBR). Better, all things being equal...which may not be the case. Obviously a poor quality HNBR can easily be worse than a good NBR.

The wisps and flakes are usually an indication of either extrusion failure (too soft) or the O-ring having been pinched and sheared. Based on the pictures I think it is extrusion. There may also be a snowball effect at play here. If the cylinder has been disassembled and reassembled, some of the loose material can get trapped in the gap, preventing the two halves from threading together fully. The resulting gap will then make extrusion ever more likely.

Anyway assuming the pictured O-ring isn't already 90 durometer, that would be the thing to try. Plain black Buna-N, green HNBR, or Viton will work perfectly well in this application.

 

[Motorhead]

If not mistaken ? .. these filters, pumps etc are coming out of China and that said ALL BETS ARE OFF as to the "If or Not" color coding of o-rings follows any established Metric or SAE standards.

Buna/N has been proven time and time again to work very well in HPA applications ( 70 Duro )



JMO ... your thoughts may differ.

 

[ashikaru]

Seconded on seeking Buna/N O-rings. These things are so cheap to begin with there's no real reason to not buy good ones.