Compression joints and spinach.

[Freddie]

Hi all,

OK...compression joints...

Hand tight and then 3/4 turn using a spanner.

When I do hand tight and then attempt a 3/4 turn...I give up.

Do I need to each more spinach?

Freddie

[sm_jamieson]

Do it up until it creaks and judders slightly. Obviously hand-tight is relative. It may be that you need *less* spinach ! Simon.

[Staffbull]

I always find I "overcook" tightening things! and then I feel I'm holding off, then ask myself is it tight enough!!! so I use solder joints or pushfits !!!

[MikeH]

3/4 of a turn sounds a lot. It just needs to be 'nipped-up'. Given my average spinach consumption, that translates to about 1/4 to 1/2 a turn for me, but no more. I also usually wrap a turn or two of PTFE tape over the top of the olive before sliding it down the pipe into the fitting. I find it helps make a consistently reliable joint.

Mike

[Freddie]

Cheers for the info Mike.

Do you put the PTFE tape on the olive or on the pipe before the olive?

So, from the pipe end, you would have PTFE, olive and then the nut or pipe, olive wrapped in PTFE and then nut?

Cheers

Freddie

[Richard Conway]

The most important thing to remember is that you can always tighten it more if its not tight enough and it leaks - but if you do it too tight and damage the olive you're buggered!

I think its one of those things that no one can tell you how to do - you just need to do a few and you'll eventually be able to 'feel' when its tight enough.

[Dave Fawthrop]

|Hi all, | |OK...compression joints... | |Hand tight and then 3/4 turn using a spanner. | |When I do hand tight and then attempt a 3/4 turn...I give up. | |Do I need to each more spinach?

Use a longer spanner. More leverage :-)

Put a bit of tube on the end of the spanner to lengthen it

[The Natural Philosopher]

Depends on what PIPE you are using. With copper its 3/4 turn. With a chromed steel pipe is a LOT less.

[MikeH]

Freddie,

Technically you shouldn't need to use PTFE on a compression joint at all. The idea is that the nut compresses the chamfered edge of the olive into the gap between the chamfer on the fitting and the pipe. With the right level of tightness the olive is squeezed into the copper pipe and forms a watertight seal. I guess if you're a professional using the things all day you quickly get a feel for just how tight it needs to be. The secret is to ensure that you don't overtighten - otherwise you'll deform the pipe and/or the olive to the extent that it will never seal. Without PTFE I found that I would occasionally get a leaky joint, but that never happens when I use a bit of PTFE. An amateurs bodge really, but it works for me - consistently.

To answer your question, no, the tape just goes over the olive so that it covers both edges of the olive. A couple of turns is enough. Once the tape's in place, slide the olive up to the fitting, slide the back-nut into place and tighten as normal. You can't put tape round the pipe *under* the olive - there just isn't room.

You can also use a sealing compund instead of PTFE tape. I've used the silicone-based Fernox one (it's called ZX or something like that - comes in a yellow cardboard box), but I find PTFE just as good and a bit less messy.

I may have misled you with my assertion that a 1/4 to 1/2 turn with a spanner once it's finger-tight will be enough. It may need a little more than that. The point I was making is that it is important to ensure that you don't overtighten. You can always give it another 1/8 of a turn if it weeps, but if you overtighten in the first place (and it leaks) you're knackered.

Mike

[Pete C]

Hi,

See also:

cheers, Pete.