Minimum temperature at which you can use Teflon pipe dope?

[Sawyer]

Does anyone know if there is a minimum temperature at which you can use Teflon pipe dope?

It is too cold here to use PL400 so I cannot put the final plate down on the last wall of my enclosure; I have to wait for 10 degrees. I thought this would be a good time to install the black pipe on the Garn but it will be down to -20 tonight and just above zero (hopefully) tomorrow.

I plan to wrap the threads with Teflon tape and apply the Teflon pipe dope after.

Thanks, George

 

[tbsdolmar]

Just warm up the dope itself . As long as it spreads on evenly and doesn't clump up I don't see that you would have any problems.

 

[Hunderliggur]

There was a discussion in the forum within the last month about tape and dope. The answer from the pros was that you use one or the other, not both. I have had better (not perfect) luck with the dope, but I learned something about applying tape better. Black pipe at 0F? Sounds like fun! At least with copper you can warm your hands ;-p

 

[rkusek]

I agree with keeping the dope warm and I think you will be fine. I know the pros in that discussion earlier said either tape or dope but not both but I don't agree with that. Someone last year suggested the tape & dope yields no leaks but I went with just the dope since my father-in-law suggested that too. Last winter we made just a simple loop to heat the barn and had about 4-5 leaks. We tried tightening and finally ended up tearind down a portion and doing the tape & dope method. My new primary loop this year is far more complex with probably 5 times as many fittings and I was a little worried about leaks. The only leak is had was a union that I somehow forgot to fully tighten. I would definitely recommend tape then dope (Rectorseal 5)

 

[Hunderliggur]

Real world meets theoretical world again! I'll try both.

 

[jf254]

I agree with everyone else keep the dope warm and you should have no problems..(Im the one that supported both tape and dope)

 

[Sawyer]

Thanks for the information, at least i will be able to do something in this weather. The good news is..........not one mosquito bite!

 

[pybyr]

I agree with everyone else keep the dope warm and you should have no problems..(Im the one that supported both tape and dope)

The quality of threads in many modern fittings is dismal compared to even 5-10 years ago (stuff being made overseas by whoever will make it the cheapest-being made with poorly set or worn out tools) and they seem much more prone to leaks.

I've taken to following the suggestion I read on here of dope-tape-dope-- and it seems to compensate for the poorly fitting threads.

 

[Sawyer]

Trevor and others, I would rather be safe than sorry. I called a licensed plumbing shop and they use both on black pipe. They too said the threads they cut are superior to supplied fittings at times.

 

[Wallyworld]

If I was going to use both and I have before, its dope first and then the tape over it. I use Rectorseal no 5 nearly everyday and have so for 30 something years. Had a few leaks but not very many. As far as temps for use, keep the dope warm and you won't have a any issues. I work outside all the time in Maine so I've fit a pipes in below zero weather.

 

[chuck172]

Hasn't anyone heard of wicking?
I use wicking and cover it with a permatex type of dope. Grip is one type.
That is what we use in the trades.

 

[timberr]

Dido for me, I used dope then tape on all of my black pipe. My only leak was on a fitting I forgot (ok maybe too lazy) to tape, luckly it was an easy fix.

Funny how temps can be relative, waiting for the temps to warm to 0*!

Good luck, glad my system is all inside. I remeber when I was installing my wife got the woodstove going a little too good and I was working in sneakers and shorts!