Compression fittings - no O-Ring?

[Gianluca]

Hello,

I am designing my custom loop liquid cooling system for my new PC. I decided to use soft tubes 10?13 (Corsair PN CX-9059001-WW) and the relative compression fittings (Corsair PN CX-9051002-WW). However, when I received the fittings today I noticed that there is no "external" O-Ring (i.e. the O-Ring that slides on the tube and that is compressed when the two parts of the fitting are tightened together.

I assumed that an O-Ring is needed for soft tubes as well as for hard tubes, is that the case? Or, rather, with soft tubes all is needed is to just plug the tube on the "male" fitting and then tighten over the "female" part? It seems wrong.

 Any help would be very much appreciated.

Thanks,

Gianluca

[LeDoyen]

there is no compression oring with soft tubing. it is the tube itself that gets squeezed against the fitting. it works like garden hoses basically 🙂

[Gianluca]

1 hour ago, LeDoyen said:

there is no compression oring with soft tubing. it is the tube itself that gets squeezed against the fitting. it works like garden hoses basically 🙂

I see, thank you, I completely missed that!

[Latharion]

Just to add a little more insight. Soft tubes attach to their fittings via "barbs".  The barb is larger than the inner diameter of the tube so it creates an initial pressure seal.  The outer part of the fitting is mostly there to keep the tube from working it's way off of the barb.  Technically, the outer part of the fitting isn't necessary, although highly recommended.  Back in the dark times, we used barb fittings that did not have outer fittings.  We used things like radiator clamps, zip ties, compression clamps or other things to secure the tubing to the barbs.

 

Hard tubing needs both pieces of the fittings to function properly, as well as an O-ring that slides onto the tubing.  There is nothing holding the tubing in the fittings except the O-rings (there is another O-ring inside the "inner" fitting).  When using hard tubing, remember to add the outer fitting, then the O-ring.  Most users have forgotten an outer fitting at one time or another.

 

[Gianluca]

15 hours ago, Latharion said:

Just to add a little more insight. Soft tubes attach to their fittings via "barbs".  The barb is larger than the inner diameter of the tube so it creates an initial pressure seal.  The outer part of the fitting is mostly there to keep the tube from working it's way off of the barb.  Technically, the outer part of the fitting isn't necessary, although highly recommended.  Back in the dark times, we used barb fittings that did not have outer fittings.  We used things like radiator clamps, zip ties, compression clamps or other things to secure the tubing to the barbs.

 

Hard tubing needs both pieces of the fittings to function properly, as well as an O-ring that slides onto the tubing.  There is nothing holding the tubing in the fittings except the O-rings (there is another O-ring inside the "inner" fitting).  When using hard tubing, remember to add the outer fitting, then the O-ring.  Most users have forgotten an outer fitting at one time or another.

 

Thanks, Latharion, all super clear now. For my first custom loop I am going with soft tubes but it's good to know what comes next 😉

G.