best way to ensure leak proof joints? All aspects of plumbing questions and answers, help, tips and information

[chris_on_tour2002]

hi,

installing a new shower valve for the mother-in-law. its being fitted to a solid wall that i am going to stud, box in and tile. as its a solid wall, access will not be possible.

so i want to ensure leakproof joints. obviously i shall test everything before i box in and all pipework will be soldered. i am concerned about the ¾" copper to iron connections to the shower valve. they will not be fully tightened as i cannot get the necessary angle to connect up to the pipes.

there are two male threads that receive female iron connections (h&c inlets) and one female that receives a male iron that goes off to the hose.

simple question, what is the best way of making these joints watertight?

ptfe is the obvious but can leak over time. or would fernox jointing compound be a better option? i've even considered hemp and boss white but most modern threads are not the type with the grooves to receive the hemp.

i'm wondering if there is a concensus of opinion out there. i suspect that ptfe would be the most popular choice...?

[htg engineer]

For male to female joints all you need is PTFE tape. The only worrying thing is - 'they will not be fully tightened' that'll be the main cause of not having a watertight seal.


htg

[chris_on_tour2002]

thanks for that htg - the fact that i cannot fully tighten the irons is my biggest concern. if i do fully tighten them they end up pointing in totally the wrong direction as they are 90° bends. the flanges in the irons are stopping me from turning them any further. one points up, the other straight out into the room. i could replace for straight irons i suppose but i am tight for space and would have a lot of pipework to redo!

[htg engineer]

If you have a problem getting them pointing in the direction you want, try a few more turns of PTFE tape, this will make a tighter joint and you will find it'll also change the direction the fittings face.


htg

[chris_on_tour2002]

thanks htg, i went with ptfe in the end and have leak free threads. gonna leave it exposed for a couple of weeks and run water through a few times just to be sure before i box it in!