Pipe Thread Sealants: Teflon Tape vs Pipe Dope | Apex Flow

Tapered pipe threads (NPT) seal on the threads themselves, and the small spiral gap between the thread flanks must be filled to stop leaks. That is the job of a thread sealant — either PTFE thread-seal tape ("Teflon tape") or a paste sealant ("pipe dope"). Choosing the right one, and applying it correctly, is the difference between a dry joint and a slow weep. This guide compares the two, breaks down the PTFE tape color codes, and shows exactly when each is required — and when no sealant belongs at all.

Apex Flow Solutions supplies brass and pipe fittings along with the thread sealants that go with them. Use this guide to match sealant to service.