Getting a good seal on compression

[curious_mal]

I am just about to put the finishing touches to adding a couple of new radiators and was wondering it there were and trade tricks to putting on compression valves. I have heard people say use jointing paste on both the threads and the olive, and I have also seen the same said but with ptfe tape.

Any tips and advice on how to do this would be greatly appreciated.

thanks

 

[kevplumb]

paste or tape on the olive it does jack on the threads hand tight then 1/2 to 3/4 turn with the spanner

 

[curious_mal]

Thanks Kev.

If I use tape do I wrap around the olive and overlap onto pipe and how much, a couple of times around?

 

[andytheplumber]

The manufacturers recomendations is that do not have to use anything on compression fittings. Just tighten with a spanner.

 

[kevplumb]

3 should do

most leaks on compression are caused by overtightening

 

[petit_pablo]

I just use a little silicon grease on the inside of the fitting where the olive would sit normally. Putting anything on compression threads is pointless

 

[curious_mal]

Well the layman has had a look at a valve and I can see the threads play no part in the seal at all, it is down to the olive etc.

Thanks for the advice. I will be careful not to overtighten.

 

[Gasguru]

The manufacturers recomendations is that do not have to use anything on compression fittings. Just tighten with a spanner.

What the f**k do they know about the real world. Run a suitable paste around the olive and a little on the threads to reduce the friction.

Went to a job today, half the 42mm compresion joints were leaking /scaled up after only 5 months...all due to lazyness.

 

[kevplumb]

I just use a little silicon grease on the inside of the fitting where the olive would sit normally. Putting anything on compression threads is pointless

so why do "conex sanbra" recommend a smear of jointing paste then

muppet

apologies gg crossed post

 

[Gasguru]

And I'd add that it's even more important these days with the reduction in quality of the fittings (ie the machining accuracy) and the fact that so many more systems are presurised.

 

[JohnD]

kevplumb

Joined: 18 May 2004
Posts: 12678
Location: Tennessee,
United States of America

On a trip, are we?

 

[kevplumb]

yup all 12 weeks

look on the map for ashland city clue its near nashville

 

[petit_pablo]

I just use a little silicon grease on the inside of the fitting where the olive would sit normally. Putting anything on compression threads is pointless

so why do "conex sanbra" recommend a smear of jointing paste then

muppet

apologies gg crossed post

Ive no idea why they recommend that. And how does me not doing what conex say make me a muppet?

 

[Balenza]

Conex state.....................

The Conex compression joint makes a metal x metal seal
which normally eliminates the need for jointing
compounds and sealants. On larger sizes, particularly
54mm, it may be necessary to use an additional WRAS
approved sealant. Jointing instructions, when using
sealant, are available from our Technical Department.

I 've always acheived a good joint just using ptfe lubricant on anything domestic. Domestic compressions joints are expensive and usualy used where dismantling is needed or should be.
So why paste them up with some sort of messy seizure inducing paste ?.

 

[kevplumb]

there ya go john