Teflon Tape on Union Threads?

kristof

Active member
Jun 8, 2009
37
Pittsburgh, PA
What's the consensus about using teflon tape on union threads. I know that it's the union o-ring that seals and not the threads but I've heard it said that the decreased friction on the threads allows the union to be tightened better which compresses the o-ring better which makes for a better seal. Also, it supposedly makes it easier to disassemble the unions when the time comes.
 

JasonLion

TFP Expert
Platinum Supporter
LifeTime Supporter
May 7, 2007
37,880
Silver Spring, MD
I suppose it might help a little, but I don't bother. A properly made union goes together and comes apart again very easily.
 

Durk

Well-known member
Jun 14, 2007
654
New Jersey
I used to use Teflon tape on galvanized unions and Dresser couplings as those would lock up due to corrosion. I have never done it with PVC. You can crack a PVC union nut by over-tightening with or without Teflon.
 

Terry

Well-known member
Jul 8, 2008
128
Dallas, Tx
JasonLion said:
A properly made union goes together and comes apart again very easily
Can you tell me what constitutes a properly made union? I bought some unions to allow removal of my mpv, but I bought the glue in version. Do I need the screw in version? Never installed a union before so any pointers are appreciated!
 

JasonLion

TFP Expert
Platinum Supporter
LifeTime Supporter
May 7, 2007
37,880
Silver Spring, MD
For swimming pool use, you normally use "slip" style unions, which glue to the pipe.

Some of the super cheap unions can be slippery when you try to grab them, or have threads that bind up. A good union will have a large textured area where you grab to tighten or loosen it and will have threads that smooth and turn easily.

They are reasonably easy to install. The key thing is to make sure the two pieces of pipe that the union is connecting together line up well. If the two pieces of pipe meet at an angle, even a very slight angle, it will be difficult or impossible to get the union together properly.
 

X-PertPool

TFP Expert
In The Industry
Jun 12, 2009
1,385
Exeter, PA
I'd recommend something similar to jack's lube as an anti-seize (if anything), i wouldn't use teflon tape in this situation.
 
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