Compression joint leaking

Sep 26, 2004 14 Replies

Just been doing a bit of plumbing in the bathroom. I've fitted a 15mm isolator valve in the feed to the wc. I suspect the copper pipe is the old imperial 1/2" dia but I understood that the 15mm fitting would be ok. I've tightened the nut on the isolator valve as much as I dare but I've still got a small leak. It seems to be coming from between the pipe and the nut rather than from the threads of the nut. (I put PTFE tape around the thread). What's the best way to get a watertight seal?



Nodge


PTFE tape should be put around the olive not the thread, after all it's the olive that seals.

Dave Jones

I know that people *do* put PTFE tape round olives - even though it's really meant for sealing tapered thread joints. For difficult compression joints, I prefer a smear of Boss White or Plumbers Mait round the olive.

Did you use PTFE around the olive ?

Nodge formulated on Sunday :

Copper olives are best used where an old imperial pipe is to be connected to, copper has more 'give' than the usual brass olives.

No, I only put the tape on the thread. I'll try unscrewing the nut and putting tape on the olive. I would think this would only give a seal between the mating surfaces of the nut, valve body and the olive. I suspect the leak is between the olive and the copper pipe. Nodge

"Nodge" wrote in news:0%E5d.149$ snipped-for-privacy@newsfe6-win.ntli.net:

Compression joints don't require anything at all; I use a bit of grease on the moving parts, and they shouldn't need a terrible lot of tightening.

Worst case - you may have a deformed pipe, (and you may have just deformed it) in which case a new bit will have to be inserted, or replace the run if reasonable.

It may have been a faulty olive; the olive certainly will be faulty by now! Try again with a new olive. (You can buy them separately, in case you weren't aware)

mike

That is a good idea!

Another thing to look for is a scratch / groove along the pipe under the olive- enough to give a slow leak (been there etc).

Don't use PTFE tape on compression joints, a bit of "boss white" or "hawk white" is OK. Also make sure the mating surfaces are clean and undamaged.

(Oh, and Harry is another radio amateur lurker. This group is full of us!)

Reminds me -- standing in a plumbers merchant, dressed in suit for wedding, whilst we try dropping olives on the floor. You'll find a

22mm brass olive gives the best impression of a gold wedding ring for bounce and sound, if you're the best man and you intend to pull a stunt where you drop the wedding rings on the floor at the last moment (not the real ones, obviously). Copper ones don't sound right, and aren't the right colour. 15mm ones sound too tinny, and the audience at the back might not see them so well.

Try Fernox sealer. It's the dog's dangly bits - works on any mixture of materials I've tried. Pricey but worth every penny.

The thread has no sealing effect on a compression fitting.

The seal is between the olive and the pipe, and the tapers on the ends of the olive and the corresponding ones on the fitting. If there is any damage to these - deep scratches etc, it won't seal. Worth also looking at the tapers on the fitting to make sure they have actually been machined - I've come across one that wasn't.

I checked again this morning and it seems to have stopped leaking. Maybe the olive compressed a little more overnight. I think I'll leave well alone and see how it goes.

Nodge

That's also one of the few benefits of hard water. Normally takes a few days for it to seal up a slow dripping joint though.

snipped-for-privacy@cucumber.demon.co.uk (Andrew Gabriel) wrote in news:cj7h15$hem$ snipped-for-privacy@new-usenet.uk.sun.com:

Also helps to have a few spares when you drop the real ring down the crypt

mike

"mike ring" wrote | > Reminds me -- standing in a plumbers merchant, dressed in | > suit for wedding, whilst we try dropping olives on the floor. | Also helps to have a few spares when you drop the real ring | down the crypt

Or when the bride's got swollen knuckles from a catfight at the hen night and it's a shame to cut the real ring so it slides over the bruises.

Of course, you don't have to marry a Glasgow lass.

Owain

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