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Active Member

Posts: 9

Location: USA


Tuesday, November 18th 2003, 7:23pm

threaded connection wont stop leaking!

how many wraps of teflon tape do you use? I have tried 3 wraps, 6 wraps, 8 wraps. I hand tighten and it slowly leaks. Then half a turn with a wrench. Still leak. Another half turn with a wrench. Still leaking. Another half turn. Still leaks. Another half turn. Still leak. So then I try a new male fitting. 3 wraps of tape, then 5, then 6. Hand tight and then 1 to 2 turns beyond with a wrench. The slow leak just wont go away!

I know your not supposed to use pipe dope on plastic, but I have seen Oatey teflon thread seal compound that instructions on can says is safe to use on plastic and PVC threads. Do you guys agree it is ok to use on plastic threads or will it ruin it?

Or can you just tell me I am doing something wrong with the tape?

Or should I not worry about a slow drip. It is like one drop every 10 minutes. Is it your experience that these slow drips plug themselves up over time? Or is it your experience that slow leaks always get worse over time?


Supreme Member

Posts: 376

Location: USA


Wednesday, November 19th 2003, 6:12am

Great questions. I will Wait for the answers too. Sorry I can not help.



Supreme Member

Posts: 462

Location: USA


Wednesday, November 19th 2003, 5:16pm

What is the male fitting threading into? I backflow preventer, or another female adapter, valve? I put liquid teflon on the male fittings going into the PVB.


Active Member

Posts: 9

Location: USA


Wednesday, November 19th 2003, 6:31pm

I've got a 1" brass female threaded ball valve. Then a 1" x 2" long male PVC nipple. That screws into a 1" Rainbird RBY filter with female threads which is made of nylon or glass filled nylon I think. Its not made of regular PVC. Its rated to 150 psi I believe and is designed to be upstream of a drip zone control valve.

It was leaking on both male ends of that nipple. Today I took it apart again and tried a third nipple with 3 wraps of tape and this time after tightening close to 2 turns with a wrench beyond hand tight on both ends it seems that its not leaking anymore where it screws into the ball valve, but is still leaking V-E-R-Y S-L-O-W-L-Y where it screws into the filter. I checked it 2 hours after assembly and the ball valve connection was dry and the filter connection had 1 small drop hanging from it and nothing had dripped off yet (I put a dry bucket underneath).

Do leaks always get worse and worse? or do you think I could get away with leaving it? These connections are upstream of the valve, so they are under constant pressure.

Oh by the way... what do you believe is best when both male and female threads are metal, like a copper male fitting going into brass female fitting. (A) Teflon tape or (B) pipe dope thread seal compound?

Rays Sprinklers

Supreme Member

Posts: 493

Location: USA


Monday, December 29th 2003, 10:28am

wat way are you wrapping the teflon? YOu must wrap the threads BACKWARDS (opposite of the directions you thread them) otherwise it serves no purpose. Make sure you wrap tight, and rub you hands around the tape to make sure its tight,,,,,definatly make sure you wrap backwards!
Rays Above and Beyond Automatic Lawn Sprinklers


Advanced Member

Posts: 230

Location: USA


Tuesday, December 30th 2003, 8:02am

You might also have a small crack in the thread or chipped edge. Also be sure you are wrapping

rain man

Active Member


Monday, January 19th 2004, 3:04pm

Are you sure it's not cross threaded or was cross-threaded when you first put it together? If so you may need new fittings. I always turn my fittings counterclockwise until I feel the threads match up, then I start tightening. It takes a few times but once you get it down is assures that you will never crossthread again.

-rain man


Supreme Member


Monday, February 9th 2004, 5:40pm

I hate for my first post to be a contradition to someone else's post, but the following doesn't make any sense: "You must wrap the threads BACKWARDS...otherwise is serves no purpose"

It seems to me the primary purpose for the tape is to fill in tiny little gaps that will exist. I believe it accomplishes this by basically gumming up the works, because the tape itself is so thin that the treads should just cut right through it (after all, we can tear through this tape with our bare hands).

It seems like the MAIN trick to using teflon tape to seal all the leaks is to make sure you are using enough tape so that it will "gum up the works" and seal everything. I've even run into a commentary somewhere else on the internet that pointed out that today's tape it much thinner than it used to be, so where people used to use about 3 to 5 layers of tape, 5 to 8 might be more appropriate.


Supreme Member


Tuesday, February 10th 2004, 4:49am

What size teflon tape are you using? Don't use 1/2" width on 1" threads. I always use at least 3/4" or 1" width. I wrap 3 times, hand tighten, then wrench a half turn or so. You really develop a feel for this after awhile.

Liquid teflon on pvc seems to lead to overtigthening since it acts more like a lubricant.

If you want to go the paste route, use a teflon free paste on pvc

Big O



Sunday, October 3rd 2010, 11:46pm

Hi segask,

I have a similar situation where the thread to the valve leak very slowly (even though I used teflon tape) and tighted it very tight. I am starting to wonder if it is possible to over tightening it and possibly caused a crack (I used a wrench)?

Anyways, just curious if you found out if the small leak plugged itself up (got better) or if the leak got worst over time or if the small leak remained the same and you considered it good enough since it was out doors (in my case, the spinkler valve)?


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