I've just installed another shower mixer ( an expensive Grohe one ), and as per usual, the connections to it are 1/2" BSP parallel.
The male BSP <-> compression adapters I obtained are a rather loose fit before we apply thread tape, and being a parallel ( as opposed to BSP-taper ) thread, they don't tighten up as you spin them on. They bottom out.
On goes the PTFE tape. In order to make even a vaguely 'tight' fit, I need to use what I consider a huge amount of PTFE tape. Something like 10 wraps or more. The threads are almost no longer visible beneath the tape! Then we tighten it up. Again, since it's a parallel thread, it doesn't get satisfyingly tighter as we do it up, it just continues at the same torque until it bottoms out. The more layers of PTFE, the higher the tightening torque.
This kind of works ( in as much as it usually remains watertight ), but is most un-satisfying. One of my connections then developed a 'weep', and I had to re-make it. Naturally, it was the most awkward one to get at. All in all, I'm fair scunnered of the "PTFE tape and BSP-Parallel threads" connection. So I'd like to look for an alternative, perhaps a jointing compound.
What I'd like to know is this:
What is the correct use of jointing compounds like LSX? Is it used *instead* of PTFE tape? How would it perform in the scenario I described, where a male BSP-P fitting is a fairly loose fit into the female? Is the viscosity enough to fill the helical leak path along the thread? Does it 'set' and provide mechanical strength as well as a seal? Or do I rely on bottoming out the fitting to loose the 'wobble', and let the LSX fill the helical leak path?
Or is it not suitable for this application?