Originally Posted by
Bruce Wrenn
Teflon tape ISN'T a sealant! Pipe threads are tapered, and seal by tightening. The Teflon tape "greases" the threads to allow for extra tightening. Some products (Rector Seal #5 as an example) are true sealants. Teflon tape isn't allowed on gas lines, as it can shred off and lodge in gas valves, causing them to leak. Yes. I know the big box stores sell the extra thick yellow stuff, but it still doesn't pass code. Holder of both P-2 and P-1 plumbing licensees in working years.