Does anything exist that you can paste round a compression fitting that may help if it springs a leak. I have a compression fitting on the top of a copper pipe from which a shower head is fitted. This compression fitting for whatever reason came slightly loose and leaked. Because this was all buried in the wall and I have approached it from the back of the wall it has been difficult to access. I beleive I have tightened it enough to stop the leak, but would like to put some magic compoungd around it in case it springs a small leak again. Does such a compound exist?