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thread dope

midway_2 Member Posts: 42
I know the answer has been on here before, but at my age, if I don't write it down its lost. One more time and this time I'll write it down. Question.. What is the best dope to use on the threads when installing a new Hoffman A-1 vent (or teflon?) One pipe steam system. Thanks


  • jim lockard
    jim lockard Member Posts: 1,059
    we save the

    best dope for special events. A little teflon paste should be ok for the vent Best Wishes J.Lockard
  • mtfallsmikey
    mtfallsmikey Member Posts: 765
    I still like

    My Rectorseal #5.
  • ScottMP
    ScottMP Member Posts: 5,884
    I used to use

    a mexican pipe dope but that was back in college.

    Rectorseal does the trick.


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  • Ken_40
    Ken_40 Member Posts: 1,320
    If it's steam...

    Do NOT use any dope containing "oils." Alcohol based dopes are okay; teflon "tape" is best; as long as you avoid the first thread or two...

    Since most vents are brass (chrome plated or bronze painted) as long as the threads are clean, you can install them "dry" (no dope whatsoever).

    The problems with oil based dopes is the drooling of the dope back to the boiler, especially when heated. One drop of oily dope residue, after it finds its way back to the boiler can make a boiler prime an surge like a bandit!

    Stay away from all the dopes noted above. Teflon tape would be my first choice, carefully applied.

    Dan was kind enough to let me post this years ago:

  • Chris_82
    Chris_82 Member Posts: 321

    Any dope improperly applied, like a kiss from a St. Bernard dog, is a little sloppy and a sign of poor workmanship is what I think you are hinting at? No. 5 can be applied carefully and you can still walk away without having to worry about cleaning the stuff off your hands. Perhaps as you also hint at a good (little) cleaning with a thread cleaning tool and a judicious amount of torque when these vents are installed may be more sage advice. Don't crank the things into the radiators! Regardless of any thread sealant/lubricant used. Finger tight is fine! Anything past that and it creates a problem down the road trying to get these vents removed.
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