How much PTFE?

[oilman]

Well the gas ptfe manufacturer says one wrap with a 50% overlap.

 

[eddg]

ChrisR mentions you should you never ptfe the threads of a compresion joint, why is that?

 

[chr15]

ChrisR mentions you should you never ptfe the threads of a compresion joint, why is that?

Cos it aint gonna do no good, a waste of time and energy, if you put it anywhere it needs to be on the olive, I prefer to use jointing paste meself.

 

[eddg]

oh right, i didn't know you could do that, how many turns on the olive is recommended?

 

[chr15]

3 or 4, you dont always need it but some people prefer to do it anyway to save time dismantling the joint afterwards, once youve done a couple you will get used to how much to use. What you are trying to achieve is a water tight joint between the olive and the cap nut, where the pipe comes thru the centre.

 

[eddg]

oh right i get you, hadn't thought of that. Just done my first few bits of plumbing recently and did some compression joints which were ok, i will take your advice on the next lot! Fitting a new bath and shower soon and i think i'm going to have a crack at soldering with a blowtorch on the joints, should be fun!

 

[Softus]

When people say "put some PTFE tape on" - how much is some?

It depends on the type of fitting and the gauge of pipework.

How many layers of PTFE tape do people wrap round a thread to seal it?

A minimum of four, but more if the thread is parallel and loose or the pressure is high.

Or does it not matter?

It is mostly done by 'feel' - an art, not a science.

What you are trying to achieve is a water tight joint between the olive and the cap nut

Actually no - the wet joint is where the olive meets the fitting; the capnut should never get wet.

 

[chr15]

No, the capnut should never get wet, but if it does, and it often does, and if the olive is tightened to its full extent then ptfe will stop it leaking between the pipe and capnut, rather than putting it on the threads, thats what I was trying to say.

 

[holty]

often found if you put ptfe on the thread to a stranderd compresion joint, in time it could crack the nut ,due to the design.there not ment to have ptfe on the sole basis that the olive will do its work

 

[DCPlumbing]

Another use for PTFE!

Small cut on finger (comes with the job) No plasters in the first aid box (Surprise) a couple of wraps of PTFE followed by a couple of wraps of pvc tape. Fixed.