Some ***** cross threaded my PVC pipe

[Gpag]

As the very last step of replacing my Irrigation PVB, when connecting a brass male threaded outdoor hose bib to a PVC tee I cross threaded the PVC threads. My only excuse is that it is close to the ground and I was working pretty much by feel.
Anyway, I do not want to have to cut off the PVC tee and connect a new one. Is there a way to repair the threads? If not, how can I connect the bib to the PVC and not have it leak? I don’t care if I have to make this a permanent connection.
If there is no way to repair it I would just eliminate the bib and cap the hole. How would I do that?
Thanks.

 

[havasu]

Many will say several wraps of Teflon tape may work, but without pics, it is hard to determine how messed up the threads are. I would also add some Rectorseal #5, which lubricates as it seals. Just understand, by screwing a male brass into a female PVC connection, you will be prone to cracking the PVC.

 

[Gpag]

Here are some photos. The bib is tight but I haven’t tested it. I expect it to leak.

 

[GReynolds929]

Depending on how bad the cross threading damaged the threads it mibe possible to carefully thread the bib in and recut the original threading. I would use pipe dope instead of thread tape in this case.
The bigger issue in my opinion is the brass male into a plastic female. It will eventually crack, the best option would be to remove the tee and replace with a solvent tee and couplings, then use a PVC x metal female, or a PVC male and brass coupling for the hose bib connection.

 

[Gpag]

I did it this way because that is the way it was with the old PVB. The plumbing supply dealer didn’t have such a tee but the irrigation supply did. That leads me to believe it is common on an irrigation system.
I think I’m going to have to bite the bullet, cut the tee off and cut the pipe inside the house so I can add a new tee.
Arggh, I was this close to being done.

 

[Twowaxhack]

Brass screwed into plastic isn’t a good plan.

 

[Ludington]

Brass screwed into plastic isn’t a good plan.

Is that because of the natural tendency to overtighten it ?

 

[Twowaxhack]

Is that because of the natural tendency to overtighten it ?

Brass expands at different rates than plastic. Plastic doesn’t do well when over tightened and it’s easy to over tighten.

 

[breplum]

Not only is metal threading into plastic a bad idea, my recollection is that UPC actually prohibits such joints…of course UPC doesn’t pertain to irrigation so it is not relevant legally…
But it is a practice that should be followed because of the reasoning and experience that plastic female threads have HIGH tendency to crack.
Dead plumbers trick would be to use a hose clamp on the FIP fitting.
NEVER USE PLASTIC FIP FITTINGS WITH METAL MIP ADAPTERS

 

[Ludington]

Not only is metal threading into plastic a bad idea, my recollection is that UPC actually prohibits such joints…of course UPC doesn’t pertain to irrigation so it is not relevant legally…
But it is a practice that should be followed because of the reasoning and experience that plastic female threads have HIGH tendency to crack.
Dead plumbers trick would be to use a hose clamp on the FIP fitting.
NEVER USE PLASTIC FIP FITTINGS WITH METAL MIP ADAPTERS

Hmmmm, how about down inside my well pump, the pump has a plastic female threads to attach to, and I believe the plastic attached pipe is using a metal connector (allthough I don't remember what I used , stainless i think) I will assume since I didn't crack it initially, and the water temp doesn't really change, that connection is fine.

 

[CT18]

Is that because of the natural tendency to overtighten it ?I was always told metal receives plastic. Plastic does not receive metal.

 

[Riickk]

AT a small depth (from 12 to 40 feet) below the surface of the earth the temperature is constant throughout the year.......

https://www.scientificamerican.com/article/the-temperature-of-the-earths-inter/