HI, new here and I know others have had similar problems, but I just wanted to present my issue and see what you all thought. Anyways I purchased a new shower/tub fixtures for my bathroom. When I removed the old tub spout (it was the universal type sold at home depot) the copper stub sticking out of the wall was just 1/2" copper pipe and utilized one of those plastic adapters that come with the universal spouts in order to hook it up. The new fixture I purchased had only the tub spout with the 1/2" female threaded end to attach to. So I sweated a cooper coppling and male adapter onto the end of the cooper stub (I believe I got the overall length of the stub correct because when I thread the spout on it fits tight to the wall). So anyways I tried teflon tape and even pipe compound, but the spout must be filling with water and when the diverter is engaged the back pressure must be forcing water through the back of the wall. I tried to silicon the hole in the wall, but Im sure the water is just finding some small hole and I have a light trickle of water inside the wall. I noticed many people talking about using an o-ring when installing these things. My spout did not come with an o-ring, but do you think this might help? If so what would I do, buy a 1/2" o-ring, slip it over the copper stub onto the threads and then screw the spout on? Would this essentially create a seal when the threads of the male end are screwed into the female end? Thanks in advance for the help. This has been killing me for days. Also, on a related note has anyone had experience with Shark Bite fittings and are they safe to use in a wall that would be closed up? I used them to attach the pipes to the new shower/tub rough-in. I was a bit hesitant to sweat joint inside the wall.