Help with PVC threaded to Brass without leaks.

[Charlie Bosco]

Ok so some of you are following my plumbing issues and now I need to redo the layout this weekend.. I am no professional but I did work as an apprentice plumber for 2 years as a teen. I did everything from sweating copper, gluing PVC and even threading and installing iron gas pipe.. the biggest enemy of a plumber is a frigging leak! Even when you do things right.. there are still gremlins.

So I want to make sure I do this right the 1st time.. My nemesis is always going from PVC to metal with threaded PVC adapters..
My reroute involves a few areas where I need to use a 3/4" PVC threaded Male adapters. For my Brass Ball Valve, Brass Spin Down, and Fleck Bypass valve. I hate installing these and always keep my fingers crossed.. I never do that with Primer and Glue..

I am ready for bear this time. I have my 3/4" Blue Monster tape and Thread paste. I really want to be specific here..

I read this from from Lasco site. I know if I followed these rules verbatim I would have a leak every time.. also WTF is finger tight? Also 1 or 2 turns, if the 2nd turn wont hurt then why not 2?

• Don't over-tighten joints by giving them "one more turn to be sure. "Do finger tighten plus one or two turns - No More.
• Don't wrap Teflon tape or Teflon paste or pipe dope to add bulk to or to lubricate the joint. Do use a sealant for threaded joints.
• Don't use "stronger" Schedule 80 threaded fittings on the assumption that they may solve the problem of splitting through over-tightening.
• Do use only Schedule 40 threaded fittings with Schedule 40 pipe and fittings.
• Don't over-tighten.
• Do finger tighten plus one or two turns.

Blue Monster also says 3 wraps.. But sometimes 4.. well which is it? is 4 better? also should I use a light coat of paste over the tape?

What procedure could I feel comfortable that a professional would use?

 

[Breplum]

PVC is not allowed to be run inside of any building (fyi). Never use inside a dwelling. 3/4" tape is for 1" pipe and larger, not smaller.
Sch 40 PVC is for outdoor irrigation or even water main if allowed and you like to make repairs as ground settles.
We use three wraps good teflon and sometimes a dash of joint compound just for lubrication purposes.
The tightening is by feel so that is just experience. Mfrs always say not to overtighten, but that doesn't help us stop leaks.
I am always getting calls to repair PVC threaded joints. PVC Sch. 40 is just cheap and soft and embrittles over time.

 

[Sponsor]

 

[Charlie Bosco]

PVC is not allowed to be run inside of any building (fyi). Never use inside a dwelling. 3/4" tape is for 1" pipe and larger, not smaller.
Sch 40 PVC is for outdoor irrigation or even water main if allowed and you like to make repairs as ground settles.
We use three wraps good Teflon and sometimes a dash of joint compound just for lubrication purposes.
The tightening is by feel so that is just experience. Mfrs always say not to overtighten, but that doesn't help us stop leaks.
I am always getting calls to repair PVC threaded joints. PVC Sch. 40 is just cheap and soft and embrittles over time.

I'm happy to say the job is done and NO LEAKS!

This in all inside of a climate controlled Storage building on my property. The PVC was there from when I purchased 3 years ago.

I had no problem with the 3/4" Blue Monster tape. 3 to 4 wraps and I left the first thread open. Then I smeared Blue Monster paste on that edge. Cranked em down by hand and then 2 turns. Not pretty. But I am not getting beauty award. Backwashing the Katalox as we speak.

I left the empty GE filter canister in the line so if I need to introduce any chemicals before the Katalox I can get it in there. Also have a gallon of Neutra Sol on standby in case I need to flush more.

 

[Eric Wesson]

It's a good questions. I too have struggled with threaded PVC joint leaks. I found that PTFE paste, along with a wrap of teflon tape, seems to work well.

I believe the reason the joints are so problematic is because the threads are cast and not cut. If you have to do this again, consider getting a tap and die for the appropriate size, and machine ("chase") the existing threads.

Bonus is you can make custom length sprinkler risers for essentially free.