Plumber’s tape is one of those small supplies that ends up doing a lot of heavy lifting on almost every job. Its purpose is to fill the tiny gaps between the threads so that water, gas or air can’t find a way through. While it looks like nothing more than a roll of plastic tape, it’s actually doing the same job as a sealant does, but without the mess or the long drying time that comes with it. This is why you’ll find a roll of it in nearly every plumber’s toolbox, whether they’re working on a bathroom reno or fixing a leaking outdoor tap.
Types of Plumber’s Tapes
PTFE
PTFE stands for polytetrafluoroethylene, and it’s the actual chemical compound that plumbers tape is made from. This material is prized for being able to withstand high temperatures and pressure without breaking down, which is exactly what you need when sealing pipes that carry hot water or gas. PTFE plumbing tapes are also resistant to most chemicals, so they won’t degrade over time.
Teflon
Teflon is the name most people know this material by, even though it’s technically a brand name rather than the material itself. Used in military gear and kitchenware, Teflon is essentially a form of branded PTFE. The two terms get used interchangeably in the trade, but when you’re buying tape for a job, you’re really just buying PTFE tape regardless of what the packaging calls it.
How to Use Plumber’s Tape
Cleaning
Before you even think about reaching for the tape, the threads on the fitting need to be cleaned properly so that nothing gets in the way of a tight seal. Old tape, rust, dirt or any leftover sealant should be removed with a wire brush or a rag, since any debris left behind can create small gaps that the new plumbers tape won’t be able to do its job properly.
Dry
Once the threads are clean, they also need to be completely dry before you start wrapping. Any moisture left on the threads can prevent the tape from sitting flush against the metal, which reduces how well it seals once the fitting is tightened. A dry rag or a bit of compressed air is usually enough to get the job done.
Wrapping
With the threads clean and dry, you can start wrapping the tape around the fitting in the same direction the fitting will be screwed in, which is usually clockwise when looking at the end of the pipe. Starting at the second thread rather than right at the tip helps prevent the tape from getting pushed into the pipe itself, which can end up restricting flow further down the line. Keep a bit of tension on the tape as you wrap so it sits tight against the threads rather than sitting loose.
Overlapping
As you continue wrapping, each pass of the tape should overlap the one before it by about half its width. This helps build up enough thickness across the threads to properly fill any gaps, since a single thin layer often isn’t enough to create a proper seal on its own. Most fittings need anywhere from 3 to 5 wrap-arounds, though this can vary depending on the size of the thread and the type of plumbing tape being used.
Final Wrap
Once you’ve gone around enough times, the tape should be torn off cleanly rather than cut, which helps stop any fraying at the end. Press the final wrap down firmly with your thumb so it sticks to the layers underneath and doesn’t unravel while you’re threading the fitting in.
What to Keep in Mind
Preparation Matters
No matter how good the tape is, it won’t perform well if the fitting hasn’t been prepped properly beforehand. This goes back to cleaning and drying the threads, but it also includes checking that the fitting itself isn’t damaged or cross-threaded, since plumbing tapes can’t fix a fitting that’s already faulty.
Too Much Tape
It might seem like more tape means a better seal, but too many wraps can make it harder to thread the fitting in correctly, which increases the risk of cross-threading. This can also cause the fitting to sit slightly further out than it should, throwing off the alignment of the whole connection.
Too Tight
Overtightening a fitting after wrapping it can crack the fitting or damage the threads, especially on plastic fittings, which are far less forgiving than metal ones. The tape is there to help seal small gaps, not to compensate for a fitting that’s been forced in too hard.
Smooth End
Leaving a rough or frayed end on the tape after tearing it off can catch on the threads as you wrap the fitting in, which pulls the tape out of place. A smooth, flat end helps the tape lay evenly and stops it from bunching up in one spot.
Proper Application
Wrapping the tape in the wrong direction is an easy mistake to make when you’re not paying close attention, and it can actually unwind the tape as the fitting is tightened rather than helping it seal. Always double-check which way the fitting turns before you start wrapping so the tape works with the thread instead of against it.
Storing
Plumbing tape should be kept somewhere dry and away from direct sunlight, since UV exposure and moisture can both affect how well the tape performs over time. Keeping a few rolls in a sealed container in your van or toolbox helps ensure they’re ready to go whenever you need them, rather than being left out where they can pick up dust and grime.