[Jamesonc]

The mixing valve seal makes sense to me. The one on the left which is meant for the plumbing where a shower head is does not make sense, at least to me.


I have two of their seals here, the 1/2 inch and the 3/4 inch. They are clearly for copper pipes or any rough plumbing that is no larger than 1/2 or 3/4.



A shower arm is not going to connect to that pipe.

 

[XSleeper]

45 degree shower elbows are generally 1/2" npt pipe (that measures .84" o.d.) so the pipe that is stubbed out should be a 1/2" galvanized nipple (.84" o.d.) with a cap. That way whoever the plumber is, he can simply unscrew the nipple from the female drop ear 90 fitting that was roughed in and screw the new 1/2" shower head 45 elbow into the drop ear fitting.

 

[Jamesonc]

I'll be playing the role of the plumber. This is what I have done so far. Will this work?

 

[Jamesonc]

45 degree shower elbows are generally 1/2" npt pipe (that measures .84" o.d.) so the pipe that is stubbed out should be a 1/2" galvanized nipple (.84" o.d.) with a cap. That way whoever the plumber is, he can simply unscrew the nipple from the female drop ear 90 fitting that was roughed in and screw the new 1/2" shower head 45 elbow into the drop ear fitting.

You're saying it's a temporary piece of plumbing? Once everything is said and done, remove it and put your finished elbow and shower head on? If that's the case, it makes sense.



However the 1/2 inch elbow does not fit into the half inch seal. It fits in the 3/4 inch seal but it's not a tight fit.

 

[XSleeper]

You use the 3/4" seal. And yes you put on the temporary nipple and you cap it so that you can pressure test the system while you can still see and inspect it. You dont want to get done tiling then discover you have a leak. Once that has been done, the finish elbow "could be" applied and caulked. Most tile layers want a temporary nipple that can be removed.

Penetrations can be sealed with kerdifix at finish.