Using paste on compression joints

[jase158]

Hi all I am wondering if it is legal to use paste on gas compression joints. reason I ask is because a friend of mine uses ptfe and paste on every single compression joint, I try not to as I would like to be able to do it without.

but this made me wonder, if we all learn to do compression with paste/ ptfe then what happens when we get onto gas and we can't use paste and then we all have gas leaks?

 

[dancinplumba]

compression joints dont require paste or ptfe

 

[PlumbBobBob]

:iagree:

 

[GrahamM]

In my opinion a new compression fitting should not require any sealing aid if done correctly. Only if it is a re-made joint do I use ptfe or paste.

Secondly, you should never use a combination of ptfe & paste together as the paste may react with the ptfe resulting in leaks.

 

[dancinplumba]

nicely put grahamm

 

[Best]

Why not use paste on olive, as long as it is recommended for gas, or whatever the pipe is for? I also wouldn't use ptfe + paste together, just paste. Compression joints dry, carrying water tend to seize & corrode, & no amount of care & experience will stop that, so not as good as pasted joints. Think of microscopic leaks! Belt & Braces, use paste.

 

[jase158]

and what about gas is it against regs to use ptfe or paste or not?

Thanks guys, this is a long argument we have been having, I said that it shouldn't be needed, he said he would rather use it as he wanted to be sure it sealed, bought myself a pair of Bahco adjustables the other day and my days of leaks are over I think. so much better.

 

[heliotrope]

Strange question.

PTFE tape on compression threads does absolutly nothing. It's the olive
that seals the joint.

Gas rated paste is ok to use on compression and threaded joints.

PTFE & Paste together on gas joints is not permitted according to
regulations.

 

[johnnyplumb]

i always ptfe olives, not required though, but lots of plumbers do it.

 

[jase158]

Why not use paste on olive, as long as it is recommended for gas, or whatever the pipe is for? I also wouldn't use ptfe + paste together, just paste. Compression joints dry, carrying water tend to seize & corrode, & no amount of care & experience will stop that, so not as good as pasted joints. Think of microscopic leaks! Belt & Braces, use paste.

My thoughts on this are that the paste is making a seal between the olive and the nut, which means the nut is not as tight as it can be which means in time when the paste wears away it will pin hole leak.

I guess there is arguments for both sides, but it feels right to me to be able to use just a nut and olive. seems a little more proffessional.

 

[GrahamM]

Most of the pastes are suitable for gas use. The main ones I have used anyway.
If using PTFE for gas, use the gas tape.

The discussion on to use or not to use paste on a new joint has been discussed a number of times here in other posts.

 

[johnnyplumb]

Strange question.
ptfe on compression threads
does absolutly nothing. It's the olive
that seals the joint.

Gas rated paste is ok to use on compression and threaded joints.

PTFE & Paste together on gas joints is not permitted according to
regulations.

aye, spot the diyer, ptfe on compression threads is usually the give away.

 

[Best]

i always ptfe olives, not required though, but lots of plumbers do it.

Either, you need it, or you don't, & the reason that many guys use paste or tape is because they know that compression joints need it. Tighten a water joint up properly & when water is on & you check the joint it may appear completely dry, but it could, & often is leaking microscopically.
Can't understand anyone not using non hardening paste. To say that a copper or brass olive tight to a copper pipe & the taper in a brass fitting will guarantee a complete seal, is dreaming.

 

[dancinplumba]

ask any manufacturer of compression joints they will tell you its not required, its time consuming and you should have confidence, just make sure its tightened right, not over tightened
imo

 

[Best]

My thoughts on this are that the paste is making a seal between the olive and the nut, which means the nut is not as tight as it can be which means in time when the paste wears away it will pin hole leak.

I guess there is arguments for both sides, but it feels right to me to be able to use just a nut and olive. seems a little more proffessional.

That's the wrong thought, IMO. The paste ( just a slight smear needed) will not stop the nut tightening tight to olive, how could it? Providing you use only a little paste, the metal parts will hit hard & the small smear of paste will fill the imperfections.
I would say that paste is the more professional job. Trust me, no leaks at all with paste.

 

[johnnyplumb]

if a compression fitting was leaking , you would probably wrap the olive in ptfe, so i think some plumbers , myself included wrap the olive as an extra safeguard. ie just in case. years ago olives where much thicker, the olives nowadays are light weight & are easily over compressed.

 

[dancinplumba]

no leaks without paste or ptfe

 

[Best]

ask any manufacturer of compression joints they will tell you its not required, its time consuming and you should have confidence, just make sure its tightened right, not over tightened
imo

Manufacturers of fittings are not hands on, heating / plumbing guys!
" Confidence " in the tightening the joint without paste, but not over tightening it, will do nothing to stop leaks.
Remember, green stains on copper pipe at compression joints are leaks, no matter how slight!

 

[dancinplumba]

never use paste or ptfe on em unless its two joints that were previously not together or over tightened, if you want to its fine
ps have posted that you have reached 1000 posts but misspelled name, put bset soz 🙂

 

[Best]

Thanks DP! Hard to believe 1000 posts already!

 

[dancinplumba]

Thanks DP! Hard to believe 1000 posts already!

yeah, did it myself the other day, time flies when havin fun, heres to the next 1000 lol

 

[Best]

yeah, did it myself the other day, time flies when havin fun, heres to the next 1000 lol

I had actually noticed earlier, that you are just ahead of me! And you joined the forum just after me. Addictive, must admit! :smile:

 

[dancinplumba]

time you joined the arms ??

 

[Best]

time you joined the arms ??

Only if I can use paste!

 

[SimonJohns]

I use jet blue plus. Only a small smear. It stops that awful screech and IMO gives a better joint.
It allows slight movement in the pipe. Easier to break fittings for future work
Ensures no future leaks