Plastic To Brass

dlcj

Ive searched the old threads and got some good tips but have not got my question answered specificly. What sealent do you use on a male cpvc fitting into a brass shower valve. Dad swears by only using sillicone on everything but i contest that this is not right and have never seen a plumber using it. But on the other hand he rarely if never has a leak while i have tried many kinds of specified pipe tread sealant and still have leaks. Someone said use teflon and pipe dope on threads will this work for cpvc-brass? Had a shower leak today didnt have time and supplies to fix, will redo it tomorrow.

stp57

dlcj,
Before the first plumber on this site tells you to hire a plumber (not a bad idea, really), go to the cpvc bin at the store and they carry a cpvc to metal coupler. This webpage is full of them, if you need a photo:
http://plumbing.hardwarestore.com/52...couplings.aspx

Steve

threaderman

Most plumbing is done by touch,contrary to popular belief,especially when referring to softer/pliable materials such as plastics or brass.Unless a manufacturer specifically calls for it ,putting silicone on everything is a joke.You're basically saying,I know my stuff is gonna leak.I use tape sometimes,dope sometimes,or a combo of both[applied sparingly].I RARELY have a leak.

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Ron The Plumber

Tape and dope together will ensure you 99.9% you will not have a leak.

Double-A

Pipe dopes and teflon tape are really designed to lubricate the threads and fill any imperfections. In a perfect world, the threads themselves would form the seal.

In an imperfect world, you get threads on CPVC that are moulded instead of cut, and hence, a less than perfect thread. Run that fitting in dry and by hand as far as you can. If the shoulder of the male CPVC fitting are up against the brass, you're going to have hell getting it to seal.

If you still have theads showing, then use a CPVC-compatible pipe dope and install it. If you want to use belt and suspenders, then put some teflon tape on it first (sparingly... two wraps max with the thin white stuff) and then some pipe dope and put it together.

Personally, I hate plastic threads and avoid them at all costs. The design in metal they are imitating calls for a full sized interior and a thin wall with threads cut into that wall. This leaves a very thin area of plastic that is quite subject to failure if it is not isolated from lateral forces. Even then, exposure to high pressure system over time can cause a fatigue failure.

Its just poor design engineering.

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highpoint

im sure you will need to solder on a 1/2 male sweat x 1/2 male threads and put on a FIp x cpvc. unless your shower valve already comes with MIP threads like the Delta valve.

dlcj

I ordered the valve npt cuz im not comfortable with soldering. I wanted male npt on the two valves in this house but one came female. Cpvc female adoptors have a rubber washer in them so that one is fine. The one that leaked the first time i just redone it and used silicone on the male cpvc threads. I know everybody will say thats a no no but it works and i didnt want to listen to dad bitch if it leaked again cuz i didnt use silicone. However i did use tape and dope on a couple galvanized nipples into brass/cpvc ells. That worked good. Thanks for the help anyway and for not burning me up on not hiring a plumber.

Grumpyplumber

NEVER use plastic threads on potable, trust me, you'll hate yourself.
Those unions with the rubber seal aren't exactly a step up in the food chain either, they're basically a garden hose adapter... but Home Depot carries them!
The ONLY way I adapt copper or IPS to CPVC is with threaded brass cpvc adapters.

dlcj

I tryed to get the cpvc/brass adaptors but the two local hardware/lumber yards did not have them. The closest H.D. or Lowes is 60 miles. Had to get it done. I also siliconed the rubber washer female adaptor threads. It worked and does not leak. I know for some reason its not right and i dont like it either but i must defend silicone and say that its been working for us for the last 15 years and no leaks still. On the next job i will order the brass adaptors early.