Liquid PTFE or Compression radiator valve - or both?!

[shabbaranks]

Hi guys,

After some searching and Googling it seems Im not the only person who is or has had this issue. Fitting a tail into a radiator you can literally screw it all the way past the end of the rad given the tolerance of the tail and the thread in the valve they can be off slightly and weep.

I know I can wrap PTFE around the thread to fill the gap but this method seems a bit of a faff and it would seem others have used liquid PTFE or a compression valve. Not to over engineer but is there an issue if I use both (given just the compression valve on its own may not be enough - unless Im wrong?)

Thanks!

 

[johnny2007]

Wrap ptfe tape in the anti clockwise direction so it doesn't come off when you screw the tail in.
Give it around 20 turns and then screw the tail in leaving just one line of the thread out.
It shouldn't leak.

 

[johnny2007]

If you use gas ptfe tape you can get away with 8 rounds of wrapping.

 

[shabbaranks]

Any reason you wouldnt use liquid PTFE? (Just out of interest as I guess there's no right or wrong)

 

[fixitflav]

Wrap ptfe tape in the anti clockwise direction so it doesn't come off when you screw the tail in.
Give it around 20 turns and then screw the tail in leaving just one line of the thread out.
It shouldn't leak.

Anticlockwise? Which way round are you holding it? This was discussed on here recently https://www.diynot.com/diy/threads/...w-rad-thermostat-wont-fit.606475/post-5418528

 

[shabbaranks]

Anticlockwise? Which way round are you holding it? This was discussed on here recently https://www.diynot.com/diy/threads/...w-rad-thermostat-wont-fit.606475/post-5418528

I guess what they mean is so its tightening as you screw it in rather than un-tightening. What if I was standing on my head whilst doing it then things get really confusing

 

[fixitflav]

I guess what they mean is so its tightening as you screw it in rather than un-tightening.

Definitely

What if I was standing on my head whilst doing it then things get really confusing

Exactly. Wrap it clockwise with the end you're taping pointing towards you. The pic in the earlier thread shows it right, despite the confusing words

 

[Madrab]

Here we go again.

OP ... Wrap the tape around the tail threads, the opposite way to how the tail would tighten into the radiator. Whether you think the wrapping direction is anti clockwise or clockwise is entirely up to you and really just a moot point, as long as it is against the way it is tightened to ensure it doesn't unravel.

PTFE paste/liquid isn't a well used method of sealing rad tails, would it work, don't see why not but do you want to experiment?

 

[fixitflav]

Here we go again.

Your pic shows the right way (clockwise!) however you describe it

PTFE paste/liquid isn't a well used method of sealing rad tails

There's plenty of thread sealing compounds out there, eg Loctite, which AFAIK aren't PTFE paste

 

[Madrab]

Your pic shows the right way (clockwise!) however you describe it

There's plenty of thread sealing compounds out there, eg Loctite, which AFAIK aren't PTFE paste

Oh please @fixitflav, lets all be adults and not start this again. My picture shows, when the tail is held in my left hand, the tape is heading opposite to how the fitting would be tightened into the rad. Call that what you want but ultimately it depends on how it is looked at.

@shabbaranks the important point here is the tape is wound on to the thread opposite to the way the tail tightens into the radiator.

 

[shabbaranks]

Thanks guys - it was more to the fact (and yes there will always be a multitude of opinions) wrapping PTFE around the joint 20 odd times is a bodge? Also when I put liquid PTFE I mean (and its my fault) thread seal.

Basically as said (and correct me if Im wrong) the issue is down to the tolerance on the thread of the tail and the bored hole in the radiator. All I want is a nice sealed joint which isnt going to leak

 

[fixitflav]

Oh please @fixitflav, lets all be adults and not start this again.

I'm just agreeing with your pic, and trying to make sure the OP isn't confused

 

[Madrab]

and trying to make sure the OP isn't confused

TBH - I don't think the OP nor anyone else would be confused when it is advised to wrap the tape opposite to the way the tail is tightened, so the tape tightens as it is screwed in.

I guess what they mean is so its tightening as you screw it in rather than un-tightening

Anyway ... moving on swiftly.

Thanks guys - it was more to the fact (and yes there will always be a multitude of opinions) wrapping PTFE around the joint 20 odd times is a bodge? Also when I put liquid PTFE I mean (and its my fault) thread seal.

Basically as said (and correct me if Im wrong) the issue is down to the tolerance on the thread of the tail and the bored hole in the radiator. All I want is a nice sealed joint which isnt going to leak

You are more than correct and whatever medium is used, it is to take up the gap between the thread on the tail and the threads in the tapping to create a watertight seal. Using PTFE tape was the next standard method to seal threads once hemp and paste went out of fashion. I do agree that the 20 odd turns of tape is excessive and it tends to leave a hugs bunch of tape at the end, that's why I use gas tape that only uses 6-7 turns. I also run a blade around the tail once it's tightened and peal off the excess tape, just to neaten it up. Thread is now a well used method and tends to be a lot neater too.

 

[shabbaranks]

TBH - I don't think the OP nor anyone else would be confused when it is advised to wrap the tape opposite to the way the tail is tightened, so the tape tightens as it is screwed in.

Anyway ... moving on swiftly.


You are more than correct and whatever medium is used, it is to take up the gap between the thread on the tail and the threads in the tapping to create a watertight seal. Using PTFE tape was the next standard method to seal threads once hemp and paste went out of fashion. I do agree that the 20 odd turns of tape is excessive and it tends to leave a hugs bunch of tape at the end, that's why I use gas tape that only uses 6-7 turns. I also run a blade around the tail once it's tightened and peal off the excess tape, just to neaten it up. Thread is now a well used method and tends to be a lot neater too.

Just to check - when you say gas tape. PTFE tape but yellow used for gas ? Guessing its thicker or something?

 

[Madrab]

Just to check - when you say gas tape. PTFE tape but yellow used for gas ? Guessing its thicker or something?

It is the tape in the yellow reels, yes. It is the same tape just thicker so less is used. I just use it as it's the stuff I carry all the time, rather than specifically water tape.