PTFE on compression joints or not???

[iceno9]

So...interesting debate time!

There are alot of plumbers who swear blind by using PTFE tape on compression joint threads (3 turns clockwise or whatever).

There are also many people who say you SHOULD NOT do this.

Reason:-
1) The seal is created by the olive crushing into the pipe and the olive against the joint - not the threads.
2) Using PTFE can clog the threads and thereby prevent the threads doing their job which is to compress the olive against the joint.
3) If the olive leaks, the PTFE does nothing anyway and the joint will leak.

So...whats everyones opinion? Use PTFE on copper compression joints or not?
What about where to apply PTFE...threads only or on the olive as well?

 

[Mindzai]

I use it whenever I have a screw thread in a plumbing joint, compression or not, and I've never had a leak caused by it. But then I'm not a plumber!

 

[Rico99]

Hi there lots of differieng theories on what to use with this.

Never PTFE on the threads does'nt do anything.

If needed then PTFE round the olives.

You could also use jointing compound on the olive.

Rico

 

[seco services]

as said ptfe on the thread is pointless just jams the thread.
abit of jointing compound will do the trick.

 

[iceno9]

ok then....so PTFE on the olive or not?

I could see the point when a crease gets on the PTFE, it creates a weak spot.....
SO if we believe that....when do you ever use PTFE?

I have also heard that PTFE acts as a lubricant on the threads....hmmm

 

[Burnerman]

If you're making a new joint, you shouldn't need it, but if you are re connecting an old joint, a wrap around the olive does no harm, together with some compound to be absolutely sure.

 

[Onetap]

It's not necessary with new joints. If you're remaking a compression joint, they will sometimes leak and a smear of PTFE paste (on the olive) will cure that. I think the olive work-hardens & won't reseal effectively. The manufacturers' recommend replacing the olives; they often won't come off.

I prefer copper olives.

 

[bathstyle]

The only time I would use PTFE tape is if I am changing a rad valve for example and the fitting has had it's neck 'wrung'.

I tend to cut the olive off, pop new compression nut and olive on and then a few wraps of PTFE tape around the olive.

I always chuckle to myself when I see PTFE around the thread of a com fitting, classic DIY territory

 

[electronicsuk]

I shouldn't think my say counts for much as I'm only a DIY plumber, but I always run a couple of wraps of PTFE round the olive on compression joints. It seems especially helpful to prevent leaking if, for any reason, the pipework does not come into the fitting 100% straight.

 

[seco services]

I shouldn't think my say counts for much as I'm only a DIY plumber, but I always run a couple of wraps of PTFE round the olive on compression joints. It seems especially helpful to prevent leaking if, for any reason, the pipework does not come into the fitting 100% straight.

then you haven't got the ideal situation for a comp fitting.

 

[notnoweric]

Gosh you live and learn
I was 'taught' to put tape on thread although could never really understand how it helps because the seal is as the olive is forced against fitting. Surely any tape on olive spoils this seal.
Also I have noticed a potential problem if replacing a com joint and using previous pipe with old olive. If the new joint has a slightly shorter 'well' your olive which is fixed is never going to butt well. You have to cut off olive.

 

[Aquaheat]

Never PTFE on any compression joint, before, after or over the olive!

Thin smear of jointing compound on the fitting side of the pipe and that's that.

Old fittings should have the olive replaced and remade. If this becomes impossible then paste will still do the trick.

If, as mentioned above, the pipe doesn't enter quite straight or is under undue pressure then the pipework should be altered accordingly.

Trade point of view not DIY.

Jon

 

[gigz]

I agree, never put ptfe on compression threads, waste of time and tape. Also never mix paste with ptfe, either one or the other, some compounds will rot the tape over time. Personally use ptfe on threads such as rad valve tails/cylinder tails. Paste on water/gas compression joints. I just smear the end of the pipe, push it in and the paste spreads over olive as you tighten. Works for me anyway. Got a mate who takes the olive out, smears the edges with paste then puts it back together. Works for him but time consuming if you've a lot to do.

 

[Steelmasons]

Always know a clueless idiot has been messin with pipes when I see PTFE on threads or olive.

 

[Whitespirit66]

Just a smear of jointing compound on the olive, if you must.

Karenolive160

• Whitespirit66
• 21 Nov 2015

A certain mod will be along in a minute to give his amateur advice on this old chestnut.