How to Apply Teflon Plumber’s Tape

• Wipe the pipe threadings with all-purpose cleaner to remove any dirt or old residue on the surface.
• Start your Teflon tape on the second thread from the end of the pipe so it doesn’t block the opening.
• Pull the Teflon tape tight and wrap it in the same direction as the threads. Usually, 2–3 wraps is enough to cover the threading.
• Apply a layer of pipe dope over the tape for extra leak protection on pressurized pipes.

Application

Wash the threads with all-purpose cleaner. Spray an all-purpose cleaner directly onto the pipe threadings and use a soft cloth to wipe it up. Try to remove any dirt, grime, or old sealant that are on the threadings so that you can get a smooth and even application. Be sure to clean both the male threads of the pipe you’re applying tape to and the female threads of what you’re screwing the pipe into. Wait until the threadings are completely dry before you apply Teflon tape. If the threadings are wet, then your tape won’t seal them properly.

Start the end of your Teflon tape on the pipe’s second thread. Hold the roll of tape in your dominant hand and the pipe you’re wrapping in the other. Find the second thread from the end of the pipe and line it up with the end of your tape. Hold the thread seal tape in place with your thumb so it lays flat against the threads without bunching up. If stray bits of tape cover the first threading or extend past the end of the pipe, they may block the flow of water or gas, which could lead to clogs or weak pressure.

Wrap the Teflon tape in the same direction as the threads. Pull your Teflon tape tight, and guide it around the pipe, following the direction that the thread spirals in from the end. As you wrap the tape, move the tape down to cover new threads and overlap half of the piece below it. When you reach the end of the threading, cut or pull the tape tightly to break it off the roll. EXPERT TIP James Schuelke James Schuelke Professional Plumber James Schuelke, along with his twin brother David, is the co-owner of the Twin Home Experts, a licensed plumbing, leak detection, and mold inspection company based in Los Angeles, California. James has over 32 years of home service and business plumbing experience and has expanded the Twin Home Experts to Phoenix, Arizona and the Pacific Northwest. James Schuelke James Schuelke Professional Plumber Our Expert Agrees: You always want to apply the tape in the direction of the threads you're putting on, which is almost always clockwise. Wrap the tape about 5 or 6 turns, then add a little pipe dope on top of that before you put in your plumbing fitting. The number of times you wrap your pipe depends on its thickness. Use 1–2 wraps for ⁄4–⁄8 in (0.64–0.95 cm) pipes, 2–3 wraps for ⁄2–⁄4 in (1.3–1.9 cm) pipes, or 3–4 wraps for 1–1 ⁄4 in (2.5–3.2 cm) pipes. Most pipe threads run clockwise, but always double check the one you’re wrapping to ensure you tape it properly. If you apply thread seal tape in the wrong direction, it could fray or bunch up when you try screwing it in, which will ruin the seal.

Press the tape down tightly against the threads. Run your thumb over the tape and smooth it out against the threads. If the tape presses tightly between the threads and you can see their shape, then you’ve applied the tape correctly and it will form a tight seal when you screw it in. If the tape bubbles away from the threads or has any edges that are bunched-up or loose, then take it off and reapply it.

Teflon Tape and Pipe Dope

Use thread seal tape and pipe dope on pipes with pressured water. Since Teflon tape could come loose if you use it alone on high-pressure water or gas lines, add a layer of pipe dope for even better protection against leaks. Always apply pipe dope in addition to tape on pipes that are part of your water supply line, or on fixtures like shower arms and sink faucets. Pipe dope, also known as pipe joint compound, is a liquid sealant that fills in the gaps between threads when you screw it in. Even if you aren’t working on pressurized pipes, many plumbers add a layer of pipe dope over Teflon tape anyway for extra protection from leaks. If you’re sealing PVC pipes, check that the pipe dope is compatible with plastic first. If you use one that’s incompatible, it could damage the seal.

Wrap Teflon tape around the threads. Start your tape on the second thread of the pipe just like you would normally. Follow the direction of the threads as you wrap the tape around the pipe, overlapping the piece below it by half. When you finish wrapping the last thread, break the end of the tape off and press it down firmly so it doesn’t come loose. If you can’t see the shape of the threading through the tape, then you applied it too loose. Take off the tape and pull it tighter as you reapply it.

Apply the pipe dope over the tape using the brush cap. If your pipe dope has a brush attached to the cap, then dip the bristles in the sealant and spread it over the tape. If your pipe dope doesn’t have a brush, then squeeze a dab onto the threadings and spread it with your fingers or an old paintbrush. Cover all but the first threads on the pipe with a thin, even layer. Immediately screw the pipe into the fitting so the sealant can fill in any gaps between the threadings before it dries.

Best Practices

Choose the color of Teflon tape made for the type of pipe you’re sealing. If you’re sealing standard water lines, then pick the general-use white tape or pink plumber’s tape for the job. If you're working on a gas line, stick with yellow Teflon tape since it’s thicker and creates a better seal. If you’re working on an oxygen line, then stick with green tape since it’s grease-free. Avoid using white general-use tape on gas lines since it’s not thick enough and could cause leaks.

Screw the pipe in until it’s snug but not over-tightened. When you tighten the pipe in the fitting, stop turning it once you feel resistance. If you keep tightening the pipe after it’s snug, then you risk stripping or damaging the threads. Even if your pipe isn’t completely tightened, the tape will stop the connection from leaking. After you attach the pipe, check it for leaks. If you still notice leaks, then you may need to reapply the tape or add pipe dope to the connection.

Skip tape or sealant on pipes with compression fittings or gaskets. Inspect the fitting that you’re screwing the pipe into for a black rubber gasket inside. Since the gaskets will already prevent water from leaking when you tighten the pipe into the fitting, adding Teflon tape won’t have any effect. Save yourself some time and money and screw the fittings together as is.