Overheard a neighbor say he never uses plumber's tape on compression fittings

I was out in the yard last weekend and my neighbor Ted was fixing his hose bib. He said he never uses Teflon tape on compression fittings because the seal comes from the nut crushing the ferrule, not from tape. I've been wrapping tape on every compression fitting for 10 years and I always got leaks. After he showed me his dry fit method I tried it on my bathroom supply line and no drip after 3 days. Has anyone else found that plumber's tape causes more problems than it solves on these fittings?

2 comments

2 Comments

the_jenny5d ago

Well now that's interesting. I've been doing the same thing for years and always wondered why those fittings would drip on me. I think the tape actually keeps the nut from fully seating on the ferrule. It adds just enough thickness to mess up the compression. I do have a question for you though. Did you notice any difference in how much force it took to tighten the nut without the tape? I read somewhere that dry fittings need a good bit more torque to get the ferrule to bite properly. Sometimes I worry about cracking the nut if I go too tight. It would help to know if you used a wrench or just hand tightened it. I have always used a wrench but I wonder if that's too much.

the_nathan5d ago

That "dry fittings need more torque" thing you mentioned. Reminds me of when I was helping my brother put together his grill last summer. He kept cranking down on those little gas line nuts with a wrench and stripped one clean. We had to drive 20 miles for a replacement part. Anyway, with the compression fitting I just used two wrenches. One to hold the valve steady and one on the nut. Hand tight at first then a quarter turn more. Felt solid without going crazy.