I am plumbing a couple fixtures (a water heater and a shower) with pex and a few threaded fittings (at the heater and shower fixtures only). At first I used teflon tape (3-5 turns in direction of thread), but all the threaded joints were leaking. So I removed all the tape and replaced it with some T2 thread sealant I had laying around. Again, all the joints leaked and some worse than before.
I've also played with different levels of tightness to no luck. Am I missing an essential step in my joins?
What other solutions exist to seal threaded iron pipe or brass joins?