Tape and dope are equally reliable for sealing pipe threads. The main advantage of tape is that it won’t smear onto your hands or tools and end up on the carpet. Here are some tips for tape:

• Cheap tape works fine, but the thicker stuff (often pink for water, yellow for gas) is easier to handle and tears more neatly.
• Unlike dope, tape is for pipe threads only. Don’t use it on compression or other connections.
• How many times should you wrap around the pipe? There are no rules, but the most common answer we got from pro plumbers was three.
• Always wrap the tape clockwise around the threads. Otherwise, the tape will unwrap as you screw the joint together.