Teflon tape should be applied to pneumatic line fittings using which steps?

• A. Wrap around the female thread
• B. Wrap around both male and female threads
• C. 3 to 4 wraps against the male thread, leave no tape hanging
• D. Wrap 1-2 times, then trim

Answer: (C)

When sealing pneumatic line fittings with Teflon tape, the seal is formed along the threaded interface, so you want the tape on the part that threads into the other piece—the male thread. Apply three to four wraps around the male thread in the direction you will tighten the fitting (clockwise as you view the end), keeping the tape flat and smooth. Start at the end of the threads and wind toward the base, then trim the tape so nothing extends past the threads before you assemble the fitting. This ensures the tape stays with the seal as the parts are tightened and avoids letting tape fragments enter the air passage.

Wrapping on the female threads isn’t ideal because it can trap tape inside the joint and doesn’t contribute effectively to sealing the threaded interface. Wrapping both threads isn’t necessary and can introduce tape into the mating area, risking debris or blockage. Too few turns won’t seal reliably, and leaving tape hanging can lead to tape being pulled into the line.