# Teflon tape on compression fittings?



## CarpenterSFO

New angle stops on copper pipe in a remodel. Compression fittings. I've never used teflon tape for them; every once in a while after putting the water back on I have to tighten up; maybe once I've had to take a fitting off and redo it.

A friend says I'm nuts - he uses Teflon tape every time. Any opinions?


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## toluene_hawk

I would not, unless they are stainless. generally those only need to be snug, not torqued.


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## The Coastal Craftsman

Plumbers paste only. If someone strangled the olive then i would just cut the olive out and put a new one on. Never seen anyone use PTFE tape on them.


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## dielectricunion

I would never use tape on any kind of compression fitting (that I've ever worked with). The threads on the compression serve to compress the mating parts, not to seal the joint. I feel like adding tape can keep the threads from tightening to their full potential and/or get between mating parts.


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## Inner10

You are probably over tightening them. The threads don't seal the ferrule does, tape or dope is pointless. If anything a little grease wouldn't hurt.


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## CarpenterSFO

Inner10 said:


> You are probably over tightening them. The threads don't seal the ferrule does, tape or dope is pointless. If anything a little grease wouldn't hurt.


Yes, usually. In one development we're often replacing 40-year old angle stops because the existing are frozen open. We strongly prefer not to change anything in the walls - we pay cash money for a couple of hours of building water shutdown, to replace a dozen angle stops and a couple shower valves, and we have to hustle. Sometimes the old fixture was cranked on and the olive is mashed into the copper. Even if we can get the old olive off without making things worse the new one doesn't always seat very well. Sometimes the old olive stays.


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## Golden view

I've had several plumbers tell me they use paste on compression threads more like a thread lubricant so it's easier to tighten and loosen. Kind of the opposite of locktite.


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## PoleBarnsNY

CarpenterSFO said:


> A friend says I'm nuts - he uses Teflon tape every time. Any opinions?


Yea. My opinion is he's the one that's nuts and does not understand how they work. 

That's like wearing suspenders to hold your pants up AND adding a belt without the buckle. :laughing:


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## The Coastal Craftsman

CarpenterSFO said:


> Yes, usually. In one development we're often replacing 40-year old angle stops because the existing are frozen open. We strongly prefer not to change anything in the walls - we pay cash money for a couple of hours of building water shutdown, to replace a dozen angle stops and a couple shower valves, and we have to hustle. Sometimes the old fixture was cranked on and the olive is mashed into the copper. Even if we can get the old olive off without making things worse the new one doesn't always seat very well. Sometimes the old olive stays.


That happens pretty often when a lubricant ain't used. People struggle to tell how tight them have the olive then over tighten/strangle it. I use plumbers paste for 2 reasons. One it lubricates the surfaces and it fills voids in the surfaces. PTFE tape can do the same thing as the Teflon helps the threads slip better but it pulls it self from surfaces that touch tight. Paste stays put much better.


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## CarpenterSFO

I'm waiting for the building folks to drain the water out of the 5 stories above us so we can get started. In order to shut off the water in any unit they have to go into a tenant's office space on the first floor, remove ceiling tiles, open some valves, and drain the 11-floor plumbing stack for 3 or 4 condos on every floor. Major PITA to get some simple work done. Scheduled weeks in advance.


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## Inner10

CarpenterSFO said:


> I'm waiting for the building folks to drain the water out of the 5 stories above us so we can get started. In order to shut off the water in any unit they have to go into a tenant's office space on the first floor, remove ceiling tiles, open some valves, and drain the 11-floor plumbing stack for 3 or 4 condos on every floor. Major PITA to get some simple work done. Scheduled weeks in advance.


Screw that go to a welding shop, get some dry ice and freeze the line. Cut the pipe and propress on a new shutoff, just leave the old pos on there.


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## dielectricunion

Inner10 said:


> Screw that go to a welding shop, get some dry ice and freeze the line. Cut the pipe and propress on a new shutoff, just leave the old pos on there.


Have you actually done that before or are you kidding?


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## CarpenterSFO

Inner10 said:


> Screw that go to a welding shop, get some dry ice and freeze the line. Cut the pipe and propress on a new shutoff, just leave the old pos on there.


It's an idea.... Some of the 11 angle stops are right on tees running up the full height of the building. It would be the end of my business here.

Maybe I'll try it in a different situation sometime. No danger of breaking a line?


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## KillerToiletSpider

A drop of oil on the threads to keep the nut from squealing when you tighten it is all I've ever used.


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## CarpenterSFO

The ones I was thinking about are all done now anyway. No teflon tape, water's back on, no leaks. Spent a couple minutes putting an ice-maker box in the wall. Seems to me refrigerators used to have a recess around the bottom foot maybe. New ones don't, and the icemaker angle stop 2 1/2 inches out of the wall doesn't work any more.


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## The Coastal Craftsman

dielectricunion said:


> Have you actually done that before or are you kidding?


It does work. I have used pipe freeze kits a few times in the past. Sure gets worrying when you start heating the pipe up lol.


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## Eaglei

Inner10 said:


> Screw that go to a welding shop, get some dry ice and freeze the line. Cut the pipe and propress on a new shutoff, just leave the old pos on there.


Yes dry ice does work ,that's what we use when replacing a water main in a finished area .


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## Inner10

dielectricunion said:


> Have you actually done that before or are you kidding?


Never, I just watched in amazement as a plumber did it.


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## KillerToiletSpider

Inner10 said:


> Never, I just watched in amazement as a plumber did it.


We always subbed out the pipe freezing to a company that specialized in it, it put the burden of liability on them instead of us.


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## dielectricunion

That's pretty crazy stuff. Never seen it done but it seems like a smart way to cut off supply when you have no better options.


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## MarkJames

A smear of plumber's grease on the threads and that will make tightening a breeze. Nothing else - no paste, no tape on the ferrule or anything. If there's a rubber o-ring inside the nut (eg. toilet supply lines, the grease can "wet" the ring, too.)


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## m1911

I never use tape on compression fittings, you aren't supposed to. I replace a lot of angle stops on older homes around here. I install quarter turn angle stops, and I only use a small amount of white plumbers dope on the treads, mostly as a lubricant, otherwise sometimes it's difficult to tighten the nut. As mentioned already, don't over-tighten.


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## MarkJames

I'm not sure if I shared this story somewhere before, but anyway....

One of my clients had just moved into their very nice, newly-built home. Hardwood, finished basement home office, walk-out, the works. Well, a pedestal sink on the first floor had a pex riser (connecting the "stop" to the fixture) simply pop out in the night, with the resulting huge amount of damage. They didn't use chrome since it didn't match. The plumber (licensed, bonded, experienced, etc.),who does a lot of that builder's homes, had installed that sink himself, and couldn't understand how it came loose. That sink had even been installed and under pressure for several weeks.

Just my hunch, but I suspect he got faked out by a nut that seemed tight, but wasn't. If he had lubed the threads first, it probably wouldn't have happened.


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## dielectricunion

On copper, I've always used sweat fittings, but I guess compressions are a lot easier to change if they're near finished or flammable surfaces. Most compressions I've removed marred the pipe so it needed to be cut back or added a coupling in order to get a fresh end. With sweat, most times you can clean up the end and sweat new valve right on.


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## hdavis

CarpenterSFO said:


> Yes, usually. In one development we're often replacing 40-year old angle stops because the existing are frozen open. We strongly prefer not to change anything in the walls - we pay cash money for a couple of hours of building water shutdown, to replace a dozen angle stops and a couple shower valves, and we have to hustle. Sometimes the old fixture was cranked on and the olive is mashed into the copper. Even if we can get the old olive off without making things worse the new one doesn't always seat very well. Sometimes the old olive stays.


Pipe dope on all the threads usually works if the seal isn't great. Old time plumber taught me that one.


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## The Coastal Craftsman

It's strange for me not to see any plumbers paste aka pipe dope on threads or compression fitting over here. Not once have i removed a fitting and found it. seen it on a couple of gas lines once on a 120 year old house. 

The stuffs good to over 10k PSI on liquid lines so should have zero issue with residential lines lol


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## Inner10

BCConstruction said:


> It's strange for me not to see any plumbers paste aka pipe dope on threads or compression fitting over here. Not once have i removed a fitting and found it. seen it on a couple of gas lines once on a 120 year old house.
> 
> The stuffs good to over 10k PSI on liquid lines so should have zero issue with residential lines lol


I've never seen a pipe fitter use anything but ProDope.


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## Marven

There are lots of different freezing systems. The best use is out in the field when you cant turn off the water.


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## The Coastal Craftsman

Marven said:


> There are lots of different freezing systems. The best use is out in the field when you cant turn off the water. Video Link: http://www.youtube.com/watch?v=jGgJ7P40-9Y


That's the kit my old boss used to have. That looks like a newer design though. They work good.


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## Inner10

Marven said:


> There are lots of different freezing systems. The best use is out in the field when you cant turn off the water.
> 
> http://www.youtube.com/watch?v=jGgJ7P40-9Y


For the money you spend on that or cold shot you could go through a wack of dry ice and Styrofoam.


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## huggytree

i use pipe dope on compression fittings...it lubes it enough to make things slide where they are supposed to...w/o it sometimes it binds up.....

your teflon tape is most likely acting the same way...letting the brass slide onto the copper


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## Quad Racer

Compression fitting require no tape or dope. If water makes it past the ferrule or the ferulle seats, the joint is no good anyway.

I can see using the dope to lube the threads but it will offer no waterproofing aid at that level of the joint. The threads of the compression fitting aren't supposed to hold water theyre designed to hold the water proofing components (the ferulle and tapered ferulle seats) of the compression joint together.


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## flashheatingand

I put dope on the ferrel, the thought is that it helps make for a better seal between the ferrule and the nut.


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## The Coastal Craftsman

flashheatingand said:


> I put dope on the ferrel, the thought is that it helps make for a better seal between the ferrule and the nut.


It don't really help that. What it does is stop the friction between the surfaces which means you can feel much better how tight you have it. When they are brass ferrels/olives it makes even more difference. Cooper is much better without the dope. 

I have seen a lot if people stop way to early on tightness and some way way too much because its hard to tell when to stop without dope.


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## flashheatingand

All I know is that I was helping a plumber, once, and he told me to put some dope on the ferrule. Previously, I would have issues with drips or leaks (gas). Have never really had an issue since heeding his advise.


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## The Coastal Craftsman

flashheatingand said:


> All I know is that I was helping a plumber, once, and he told me to put some dope on the ferrule. Previously, I would have issues with drips or leaks (gas). Have never really had an issue since heeding his advise.


I always use it. I have a few times not used it and they didnt leak but they didnt feel no where near as nice to tighten. That horrible noise the metal makes as it's grinding against it's self is reason enough for me to use it :laughing:


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## MarkJames

I just replaced a couple faucets and was cursing the guy who doped all the threads 15 years ago or so. I thought it would be a quick job and didn't have some of my cutting tools with me to speed it up underneath - the nuts to hold the faucet in place were glued to the underside with dope, etc. Threads all gooped up. Oh...and one of the angle stops (pasted ferrule) was crusty from old leaks.

Anyway, here's a plumbers thread on the subject.

http://www.plbg.com/forum/read.php?1,482429


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## Quad Racer

Yeah its always fun to find a mess with dope and tape where it doesn't belong. 

And in the thread you pasted the "plumber" wanted to move the joint after it was tightened?

You just can't teach mechanical aptitude. You either understand how things work or not. In the meantime I will just get a chuckle when I see tape or dope on a fitting that would have been dry anyway.


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## hdavis

Quad Racer said:


> I can see using the dope to lube the threads but it will offer no waterproofing aid at that level of the joint.


That's the theory. Reality is, pipe dope can seal it water tight long term. Like 20-30 years. The last one of these that I took apart was probably put together in 1986, and I took it apart in 2007, I think. No leak, ever.


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## madmax718

pipe dope in large quantities cant seal- but it can fill in areas of imperfections on the surface. Heck, you can use just about anything, (as long as it doesnt break down). You could use your boogers temporarily- it lubricates, and seals. Lol


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