Compression fittings

Marvin · 19 Oct 2010 at 19:25

I ordered some of these: 16/10mm & 16/11mm compression fittings - black nickel and some XSPC 7/16" ID 16mm OD tubing. Apparently they are compatible, but I can't see how. The tubing is a loose fit on the 'barb' part of the compression fitting, and the union nut doesn't compress the tubing in any way, so I can simply pull the tubing straight back out.

According to my measurements, the tubing is a perfect 16mm OD, so presumably the compression fittings require 16.5 or 17mm OD tubing or something?

Any ideas before I get on OcUK's back?

Also noticed the packaging was a little sub-standard - opened the box to find a good amount of 'air space' and my NZXT cables rattling around, as well as my new GTX480 waterblock...

Come on OC!

Oh, and I also tried some 7/16 Masterkleer tubing I have, and that was no better, neither was some different XSPC 7/16 tubing. 1/2" is too big in both ID and OD, so what these fittings are designed for I have no idea...

JonJ678 · 19 Oct 2010 at 21:36

The tubing should fit snugly over the inner barb section, but come off readily if pulled. However the nut should definitely compress the tubing. It takes me considerable effort and a couple of spanners to tighten the nut down on my compressions, and occasionally when removing them I find the tubing has been forced between the threads.

That's using 10/8mm generic compression fittings with 11/8mm tubing, though 11/8 on both is also a tight fit. I'd avoid the ones you've picked based on the image as there's no way to grip them with a spanner, suggesting they're intended to be finger tight only.

I'd much rather have the tubing - fitting joint so tight that I can lift the case up using one of them (I've verified that I can do this with mine) than be able to put the tubing on bare handed. I'd return those and buy uglier, better designed ones.

Marvin · 19 Oct 2010 at 21:40

I've sent them a webnote asking what tubing they reckon actually works, considering I've tried the two most common brands of 7/16" tubing, but I take your point. The thing is they also do 1/2" compression fittings, but I decided not to, as I couldn't get the right colour tubing - curse my colour matching! Which fittings would you suggest? (From OCUK's current stock)

JonJ678 · 19 Oct 2010 at 21:51

I can't in good faith recommend any of ocuk's range as there's no way to get a firm grip on one, which I think is important, and finding a photo which doesn't have a competitor written across it is proving tricky. The 90 degree fitting below should show what I mean by a place to fit a spanner though.

I've got stacks like that, no leaks or problems from any of them. Sorry I can't be more helpful

Marvin · 19 Oct 2010 at 22:25

Thanks for your help Jon - much appreciated. Just got to see what OCUK say now...

Biffa · 19 Oct 2010 at 23:35

You want 3\8" ID - 5\8" OD tubing for those fittings.

Such as the Masterkleer tubing PVC 16/10mm (3/8"ID) which comes in black, blue, green and red.

Marvin · 20 Oct 2010 at 09:45

The point is that they're advertised as being suitable for 16/10 and 16/11mm tubing. 16mm is 5/8", 10mm is 3/8" and 11mm is 7/16" - the tubing I have is 16/11 and so should work.

I've put some heatshrink around the barbed part - which makes the tubing a good fit now, and the union nut actually clamps it down. So it looks like this should work, but I'll do some more testing today. It was pretty difficult to pull the tube out as it is now, so I'll see how it goes.