Why ptfe tape on compression fitting threads

[fredyflame]

Could you tell me why I keep seeing tape round the threads of compression fittings all over the place where professionals must have fitted them?

Surely the seal is on the olive and if you tape up the thread you are working against that seal as the thread should never need to be water tight, or am I missing something?

As a DIYer I lightly paste the olive, never had a problem that a nip with the spanner didn't cure

Cheers

 

[REDSAW]

when you tape the thread it stops any seepage dripping down the thread, then diverts it up hill so it comes out of the pipe end depending which way you want the water to drip out of.

if neither, then a thumb full of lsx wiped all around the fitting will stop it coming out altogether.
it worked for the guy who installed a boiler i took out the other week, maybe if all the 5 fittings including the gas were more than finger tight he may not have needed it?.

 

[PlumbBobBob]

perhaps he was working to a rule of thumb? thumb size glob of lsx seals anything.

 

[Gray0689]

I've had to do it myself in the past, where someone before you has over compressed an olive, to such a point that they've compressed the copper pipe.

It isn't good practise. Then we've discussed putting jointing paste on olives, and the jury was split on that.

Totally agree Danny
And I use paste on olives

 

[Howsie]

Only used when necessary. Always try to stick to MI when fitting new, anything to make it work on second hand.

 

[leelister6]

Copper olives generally don't need anything on em but the brass ones always get a smear of paste after initial tightening. Based on bitter experience!

 

[thomas donovan]

amen to that leelister6 have had a brass olive on 28mm zone valve start to weep after months while owner was on holiday always wrap a bit of ptfe on olives now, belt and braces

 

[mactatty]

I only use paste on old copper tube (which might have a roughened surface) and never PTFE. PlumBlue or JetBlue is what I use, but B&Q do JetLube for £9.50 for 300g, Screwfix No Nonsense Jointing Compound £8 for 250g. Dear but a tub lasts a long time. Definitely not Boss Green - too lumpy and doesn't stick to pipework, you can't smear it on.

 

[aligorgon]

Shouldnt need ptfe or paste on a compression fitting unless its 28mm or above then i nip the joint loosen and put a dab of jet blue or boss white (heating only) on the olive and re-tighten.

Ptfe may be necessary on a old comp joint or over tightened one.

Only exception is chrome pipe i always use a dab of jet blue on comp chrome fittings.

Generally i try to avoid compression joints cos lets face they arent as reliable as sweated or even tectite fittings.

 

[ne1ls0n]

whats the big deal about ptfe'ing olives? if i dont like the connection it gets ptfe tape round the olive, peace of mind. surely its better to do it than not?

 

[barronbathrooms]

I jet blue every compression fitting/valve just habit I guess but very really get one passing. I hate boss green used to work for a firm that would supply Only boss green as a j/c could never get to grips with it! Alway ptfe magnaclean as well!

 

[SimonG]

As Dannypipe said a fortnight ago, it's one of those you'll never get agreement on. I paste olives and use a twist of ptfe and paste if remaking an old compression joint.

At the end of the day it's all about what works for you to get the job done. For me it works and I'm happy.

 

[glenno1]

I use our lass,nothing gets past her lol

 

[RPG 80]

there is no need to put PTFE tape on a olive as it is the olive which causes the fitting to be sealed Tight.

I find a wrap of ptfe round a olive going onto hep or speed fit plastic, helps prevents the fitting weeping.

 

[Howsie]

I wonder if NASA use PTFE on the o-rings on their shuttle boosters. Maybe they could learn a thing or two from this thread. :lol:

 

[Mike Jackson]

Probably used Boss white and hemp.