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thread sealant

PDB2PDB2 Member Posts: 26
In hydronic near boiler piping, is there a preferred type/brand to use

when mating copper to black iron? Or for that matter, a certain type for

all hydronic connections?

Comments

  • SnowmeltSnowmelt Member Posts: 1,258
    What I use

    Pro dope
  • jumperjumper Member Posts: 1,563
    technique can matter too

    especially with cheater thread
  • lzalza Member Posts: 40
    pipe dope

    PDB2



    Anything you use will be fine.  I personally use Hercules umm...Megaloc.  I like the consistency.  But pretty much anything will work (and my personal preference for application is a thin layer of dope, then a three wraps of teflon tape, then another thin layer of dope).  The one thing I would advise you on is your choice of fittings.  If you use dielectrics, stay away from dielectric unions as they tend to leak.  If you use a dielectric nipple, I personally always use a brass coupling and then a copper male adapter.  Copper female adapters tend to leak at the threaded joint. 
  • lzalza Member Posts: 40
    cheater thread?

    jumper,



    What is cheater thread?
  • hot_rodhot_rod Member Posts: 14,384
    I really like

    this 3- Wrap tape from Mill Rose. You really do not need to add any dope with it. Great for rough threads, and comes off the roll better, to the very end.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    The magic is in hydronics, and hydronics is in me
  • bob_46bob_46 Member Posts: 813
    Cast Iron

    The use of teflon tape or paste is not recommended for connections on cast iron baseboard or cast iron headers on coils . It is too easy to over tighten and crack the casting .
    bob
  • RobGRobG Member Posts: 1,850
    edited August 2014
    If

    If done correctly there is no problem with mating copper to CI baseboard with Teflon or paste, as long as there is room for linear expansion. At least I've never had a problem.





    And if you don't use Teflon or paste how are you going to seal the joint?

    Rob 

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