Compression joints: wrap PFTE around olive?

[mike004]

So far in my limited DIY plumbing career I have been using the following procedure for compression joints:

1 wrap of PFTE around the male connector
Hand tighten
Tighten 1 turn using spanners

It seems to work most times

But I have read a lot of posts from people who wrap a turn the PFTE around the olive, rather than the connector.

A matter of preference, or is there some technical reason

 

[gas112]

Here goes will it reach 3 or 4 pages this time

 

[mike004]

Here goes will it reach 3 or 4 pages this time

To stop a long thread, I willassume that it comes down to preference in the end.

 

[electronicsuk]

Here goes will it reach 3 or 4 pages this time

The last discussion was regarding whether or not it's worthwhile putting PTFE around the olive. This time there is absolutely no ambiguity - wrapping PTFE around the thread on a compression joint is a complete waste of time. It does nothing, as the sealing face is on the olive. The thread and nut are merely there to create pressure on the olive, not to create a seal.

 

[mike004]

Ok, I might think about changing my compression joint technique by using a wrap of PFTE around the olive.

 

[electronicsuk]

Ok, I might think about changing my compression joint technique by using a wrap of PFTE around the olive.

Here's the other discussion should you fancy some bedtime reading:

//www.diynot.com/forums/viewtopic.php?t=247447&highlight=

 

[xr4x4]

due to my experiences in the last few years, plus the appalling quality of compression fittings these days. i always put PTFE tape on the olive only.

its pointless on the threads.

they always seem to leak/seap without it at some point.

tbh i think its down to me overtighting the joints, even if only slightly, i think they need to be fairly loose to seal as to tight will deform the joint and leak.

 

[mike004]

its pointless on the threads.

To my amateur eye:
Surely, if the olive joint fails, then PFTE on the thread will keep the joint watertight. So the PFTE on the thread acts as a back up in this case.

Also, won't a wrap of FTPE on the thread make a tap connector connection more secure?

 

[1john]

Any amount ptfe on the thread will not stop water leaking from where the pipe enters the fitting if the olive join fails.

 

[JohnD]

the thread is not a watertight joint. If it was close enough to prevent water passing, it would be too tight to turn it. There are some threaded joints that are watertight, provided they have PTFE or paste on the thread; but these have a tapered thread that gets tighter as you go, and eventually is so tight that it will not turn. These are found mostly on radiator tails, and some shower connectors.

However, a couple of turns round the olive, after you have seated it, and overlapping slightly onto the pipe, is very good at making a compression joint leakproof. I am a DIYer, not an expert plumber, but since I started using PTFE on olives, they have never leaked.

Some of the old-timers will claim they never get leaks so it isn't needed. I have seen leaks so I use it. It is far less trouble than dealing with a leak later, or draining down a system to remake a joint.

 

[Axel]

Oh God no no NO! NOT AGAIN???!!!???!!!

 

[xr4x4]

the thread is not a watertight joint. If it was close enough to prevent water passing, it would be too tight to turn it. There are some threaded joints that are watertight, provided they have PTFE or paste on the thread; but these have a tapered thread that gets tighter as you go, and eventually is so tight that it will not turn. These are found mostly on radiator tails, and some shower connectors.

However, a couple of turns round the olive, after you have seated it, and overlapping slightly onto the pipe, is very good at making a compression joint leakproof. I am a DIYer, not an expert plumber, but since I started using PTFE on olives, they have never leaked.

Some of the old-timers will claim they never get leaks so it isn't needed. I have seen leaks so I use it. It is far less trouble than dealing with a leak later, or draining down a system to remake a joint.

spot on..