Suggestions on how I should correctly seal this value

[Crooksy88]

What should be a straight forward connection is proving to be something annoyingly different.

I have a 1/2 inch compression coupler which I am attaching to a new shower mixer valve (cold inlet).

The photo doesn't show this but I have applied what I thought was adequate PTFE tape (10 rotations) and before screwing the coupler in I inserted a 1/2 inch fibre washer into the valve.

Having tightened the coupler as much as possible there is a very small leak. I'm assuming the olive joint is OK but to be honest I'm unsure how to tell which joint the leak is coming from.

I'm wondering if I should be screwing the coupler in until it sits on the brass shower valve (i.e. it can't tighten any further).

Would anyone have any suggestions as to what I might be doing wrong or solutions for me to try (other than getting a plumber in 😀).

Thanks,

Mark

 

[Riley]

Use loctite or more wraps of PTFE. Plumbing isn’t about tightening everything up until it’s straining at the seams. It’s about having the experience to know when something is tight enough from feel

 

[Crooksy88]

Thanks for your reply @Riley

Something like this?
Loctite Threadlocker

 

[ShaunCorbs]

Loctite 577

 

[Crooksy88]

OK Cheers.

 

[rpm]

The coupling is touching the backplate, more ptfe required to seal the joint before this can happen.

 

[Pickwickpick]

Could just be my eyes/photo but looks like the copper pipe goes into the compression fittings at an angle, if that's the case the olive.prob isn't sealing properly.

 

[Ted808]

i think it's running down the back from the push fit

 

[Andy B]

I like to use gas PTFE tape- yellow rolls. It's thicker than standard PTFE tape.

Seems to seal better for me on things like radiator tails.

Make the tape 'cone' shaped so the first thread has little or no tape and it gets progressively tighter as you screw the fitting in.

 

[garygvl]

fitting tight down to vavle. worth a try to put two washers in as may not be seating on only one washer

 

[ShaunCorbs]

Don’t need washers

 

[Crooksy88]

Thanks for all the advice.

It does make sense that when using PTFE if I can tighten the coupler down to the valve without much resistance then I need to use more PTFE.

Looking into sealants like Tru Blu, Loctite 577 or 55 and considering these pipes are being boxed in I think I'm going to go for 577 to give my novice pipework the best chance of remaining leak free.

 

[Stigster]

It's a common problem with people DIY plumbing with PTFE. It seems like you are putting too much on when in reality it's actually not enough. I would start with around 15 or 16 wraps of PTFE tape and see how it tightens in. If I'm not happy with the feel of it as it tightens in I'll try it with another 4 - 5 wraps. Usually good by that point.

 

[Harvest Fields]

Loctite.

 

[offgridman]

Before applying PTFE to threaded joints I connect the joint counting how many revolutions until it comes to the end. Helpful if aligning taps, etc.
Apply PTFE and if there is enough on, the joint will lock up before maximum revolutions reached. On deep-cut threads, it may be be wise to try on fitting part way to seat tape into threads, then undue for a further wrap or two.
As previously said, experience can tell you when its right.
Valid point made about having pipe straight into olived joint. Finger tight first, to check if straight, and then apply elbow grease via spanner.

 

[Best]

I tend to also taper the ptfe amount on threads - build it up on last couple threads with an extra few wraps (with tape twisted to less wide) so to make a tight seal.

 

[Best]

I like to use gas PTFE tape- yellow rolls. It's thicker than standard PTFE tape.

Seems to seal better for me on things like radiator tails.

Make the tape 'cone' shaped so the first thread has little or no tape and it gets progressively tighter as you screw the fitting in.

Sorry Andy.
Great minds think alike.

I obviously didn’t read the last sentence of your above post and posted the identical thing.
Only you worded it better with the “cone” description. 🙂

 

[Andy B]

Sorry Andy.
Great minds think alike.

I obviously didn’t read the last sentence of your above post and posted the identical thing.
Only you worded it better with the “cone” description. 🙂

🙂 easier to do in practice than explain!

 

[peterwhayward]

Copper pipe does seem to be at a slight angle, have you made sure the pipe goes all the way through the olive ?.

 

[NickH]

Before you put any tape or string on the fitting roughen the thread with a file or hacksaw blade. The tape will then stay put when you wind the fitting in.
I do this on ALL threaded seals, it makes a big difference. Loctite 55 for me.