Is there a common standard for fitting a shower hose wall outlet

[Kenn7]

Hi Madrab,
Just a quick note to let you know how I got on...
I dismantled the assembly and remade the connections following your advice, no leaks no weeps, I tested it by banging it about a bit and leaving the pressure on for a couple of days, all was OK. It's now completed and the backer board in place. (The last thing you need in a wet room is to have to pull it apart because of a weeping connection).
Because its difficult to be precise about the number of turns required to seal 1/2" BSP connections I experimented on a test set up and thought the following might help as a bit of a guide...

I found than about 15 to 18 turns of plumbers (not gas) PTFE seems to be about optimal, any less and the joint can be prone the weeping, any more and it becomes difficult to start the male thread turning. The torque to seal needs to be quite a bit more than hand tight, but quite a bit less than you could achieve with a small/medium size set of grips (a bit vague I'm afraid, but I have no means of measuring torque). What I did find though is that if you do over tighten slightly and the joint starts to weep, providing you used enough PTFE tape in the first place, backing the thread off slightly can usually seal the joint. Tightening it further (which would be the natural inclination) just makes the weep worse. Over tighen a lot and it can be beyond recovery.

Thanks for all your help and advice.
Kenn7

 

[Kenn7]

Sorry I didn't close this issue two years ago when found an excelent soution to my problem.
I found exactly the coupler I needed online at BES (see photo attached), I also found I was able to buy fibre washer packs through ebay that gave all the sizes I needed. So with good solid shoulders on the coupers and the right size male fibre washer I am able to make 100% reliable connections every time.
I think the problem is the majorty of couplers have become such poor quality now it's hard to make reliable connections with them. It's a bit hard to see why they bother putting shoulders on them at all if they don't expect them to work.
And to answer your question... The valves have no female shoulder at all, there is no chance of fitting a fibre washer internally.
But thanks for your help anyway.