# Pipe dope, or teflon



## Bill

on any plastic fittings do you use pipe dope or tape? I have always been told not to use pipe dope on plastic as this lubricated the threads and will cause the fitting to go too far and crack.


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## user4

I use both on just about everything but gas pipe.


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## Ron

You are right, however, I always apply pipe dope on top of tape, even on plastic threads, never had a leak.


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## A Good Plumber

Both nearly aways, even on gas. Especially on 2-4" screwed.


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## Ron

You will find using the thicker of the tapes will give you a knowing feeling you won't have a leak. That white thin crap, is just that, crap.


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## Bill

so you never had a problem with the pipe dope acting as a lubricant to the threads on plastic? I had one that cracked, could had been me tightening too tight. Or a bad fitting. I thought maybe the dope made it hard for me to feel just how much pressure i was applying. Noe any metal threads, yes, I use both. Just not on plastic, tape only.


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## Ron

You don't want to use just dope on plastic alone, threads get to slick and will cause you to over tighten and not know it, I use very little dope on top of the tape with plastic threads. You can use just tape and it will seal just as good, I have just cone accustom to use both no matter with.


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## service guy

I use teflon tape and Megaloc™ on my threaded joints. Except on gas pipe, then I just use Megaloc™.


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## 22rifle

service guy said:


> I use teflon tape and Megaloc™ on my threaded joints. Except on gas pipe, then I just use Megaloc™.


Exact same thing I do.


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## ILPlumber

Megaloc gets hard as concrete after about a week. Any vibration and I think you will have problems. I use the white permatex teflon dope. Good stuff and stays pliable. My teacher forever ago told me NOT to use tape on plastic threads due to the fact it goes in so easy , it's easy to overtighten. I look more at the number of threads showing instead of the feel on plastic. I had an engineer one time that made us have 3 threads showing when it was made up or redo it.:blink:

I have had superb luck letting the dope set a while before putting the pressure test on it. That and getting every bit of cutting oil off the pipe after threading. I use PVC primer to clean my steel pipe cut threads. Dope sticks much better.


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## service guy

ILPlumber said:


> Megaloc gets hard as concrete after about a week.


No it doesn't. It is a soft compound like teflon paste, You must be thinking of something else.










> Multi-purpose thread sealant made with DuPontTMKEVLAR®for use on
> metals including steel, stainless steel, brass, copper, aluminum, and on
> plastics including PVC, CPVC and ABS.Leak-free joints can be tested
> and put into service at once.MEGALOC wipes clean from hands and
> tools with a dry rag, is odor-free, grit-free, and will not separate or
> settle.*MEGALOC does not harden, crack or become brittle;joints can
> be disassembled without damage to pipe, fittings, or threads years
> after the joint was made. *
> MEGALOC is applied easily with a natural bristle brush even at
> temperatures as low as -25°F, and performs over a temperature range
> of -50°F to +400°F.It provides leak-proof hydraulic resistance to 12,000
> psi and withstands gas pressure up to 2,600 psi.MEGALOCis
> non-toxic, non-hazardous, and non-flammable.It contains no lead,
> heavy metals, or volatile solvents.


You are thinking of BLUE BLOCK maybe? I hate that stuff, is gets hard as rock.


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## Ron

I use only megaloc


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## rex

white pipe dope cleans up much eaiser.....tape for plastic fittings or metal to plastic


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## A Good Plumber

"so you never had a problem with the pipe dope acting as a lubricant to the threads on plastic?"

Sorry, I didn't read that you were asking about pipe dope on *plastic.*

Rectorseal #5 says never to use it on plastic, it breaks down the polymers in the plastic and makes it brittle.

You need to read the label, or have you wife read it to you (jus kiddin), on all pipe dope to find out what it "should never" be used on.

Teflon pipe dopes, like rectorseal #100, are ok for plastics.


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## ILPlumber

service guy said:


> No it doesn't. It is a soft compound like teflon paste, You must be thinking of something else.
> 
> 
> 
> 
> 
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> 
> 
> You are thinking of BLUE BLOCK maybe? I hate that stuff, is gets hard as rock.


Yup, that's the stuff. Bout 5 yeaars ago I used it for a year. Had trouble with it. And it did get uber hard. Maybe they changed the make up of it since. I love how the can says easy clean up:laughing: I got pants with that crap still on em.


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## service guy

I still think you're mistaken. I've been using the stuff for 10 years, its as soft as white teflon paste and easy to clean up.

Its blue, so people mistake it for BLUE BLOCK. That stuff gets really hard and sticks to everything! I hate it.


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## service guy

Megaloc and teflon paste are virtually the same in consistency. They both stay soft for years. If you leave a can open, they do not get hard, even after a long time.

I am not a salesman of this stuff, just been using it forever!


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## uaplumber

I use only teflon for plastic or plastic to metal. For all metal to metal I use tape and dope,. It just gives me peace of mind that my tests will hold.


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## 22rifle

ILPlumber said:


> Megaloc gets hard as concrete after about a week.


You must use a different brand of Megaloc than I use. -wink


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## threaderman

I use rector-seal for my gas work.Sometimes I just use the thick yellow gas tape[if new pipe and fittings].
I avoid pipe-dope on plastic threads though tape makes it easier to cross thread.I think now though there are plenty of pastes that won't break down plastics or nylons.
For other NPT type threads,white or blue paste with teflon seems fine.


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## Plumberman

Just a little bit of Megalock and no tape on plastics. I only tape and dope water lines... Like on an adapter coming off a meter.


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## GrumpyPlumber

*Recently I learned silicone does wonders.*


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## Ron

GrumpyPlumber said:


> *Recently I learned silicone does wonders.*



Recently, like as in today. :laughing:


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## gear junkie

I tried megaloc and didn't care for it. I switched over to real tuff and it works much better.


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## 22rifle

gear junkie said:


> I tried megaloc and didn't care for it. I switched over to real tuff and it works much better.


+

What did you like better about it?


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## gear junkie

It just seemed to seal better. Megaloc has some friction, probably due to the kevler, and the real tuff just seems to glide tighter. I started out using oatey great white and maybe real tuff just seemed familar.


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## Double-A

RectorSeal T+2 or Number 5. 

And ya, I'm a belt and suspenders kind of guy on underground stuff sorta like Ron is. Call me anal.

Gas gets #5, anything under a sink gets T+2 as well as all brass. Plastics, same. Actually, I only use #5 on steel pipes. Go figure.

Oh, and I never use Teflon tape on plastics. I try not to ever use plastics.


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## GrumpyPlumber

*I used to like Rectum seal, until one summer in mid July a can tipped over in my tool bucket.*
*I use Pro Dope now, I like it's consistancy...the fact that I don't have to break out the rotary hammer to get it off my tools is a perk.*


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## nhmaster3015

I hate teflon tape. Buy it by the case.:blink:


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## 3KP

I use slic-Tite paste with teflon. on everything I use teflon and pipe dope on all water threaded connections. I usually don't dope my plastic threads though. some times I do put it on plastic but very rarely.


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## MACPLUMB777

*Pipe Dope Or Teflon Tape ? ? ?*

*I USE TEFLON TAPE AND SLIC TITE ON EVERTHING AND WHEN I WAS MARRIED I EVEN USED IT FOR THAT ! ! :thumbup:*


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## jeffc

I have used teflon pipe dope and teflon tape on every threaded joint that i put together except gas. then I use the yellow tape and dope or Rector-seal


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## I'mYourTourGuide

Killertoiletspider said:


> I use both on just about everything but gas pipe.


 
No joke, tape then dope everything. I've never had a leak like that.


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