I have a 3/4" PVC pipe that ends in a slip-to-threaded adapter that I'm screwing into a brass sprinkler valve with female threaded ports on the bottom. Generally with threaded connections I use "T Plus 2" brand pipe thread sealant paste (PTFE). After I applied it, tightened the connections and opened up the water supply, I see a single drop of water coming out of the threaded connection on the supply side of the valve about once every three seconds. The pipe was fully tightened down without what I'd say is over-torquing. The drip is definitely coming out of the threaded connection at the valve, not the slip joint between the PVC pipe and adapter. So, is there a doping material that you think would work better? I've never had really good luck with teflon tape, but if you want to say it's really the way to go, how many layers do you wrap? When I used to try using tape I was never able to get that right.