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How to Remove an Old, Threaded Fitting

HeatingHelp Administrator Posts: 654
edited November 2016 in THE MAIN WALL

How to Remove an Old, Threaded Fitting

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  • Boatbill
    Boatbill Member Posts: 3
    Don't try this trick on a cast fitting. :-(
  • hot_rod
    hot_rod Member Posts: 22,480
    Boatbill said:

    Don't try this trick on a cast fitting. :-(

    The two hammer method works well for breaking old cast fitting, less chance to egg shape the pipe inside when you back up the blow.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
    delta T
  • Bill_Kitsch69
    Bill_Kitsch69 Member Posts: 48
    Don't try this trick on a malleable fitting, I think Boatbill means.

    Malleable fittings will distort and crush. They will not break.
  • Henry
    Henry Member Posts: 998
    My father would say: "Play the music" when breaking cast fittings
  • saky
    saky Member Posts: 1
    Sorry to ask
    Im very new in plumbing
    But i have same situation with old black iron pipe
    I need to disconnect them
    Can i help myself with torch
  • Controlsgirl
    Controlsgirl Member Posts: 13
    Thanks for sharing!!
  • delta T
    delta T Member Posts: 884
    @Bill_Kitsch69 The 2 hammer thing works on malleable fittings, its just that you are not trying to crack the fitting, your are trying to break the bonds between the fitting and the pipe. I have successfully used this trick several times now. It just takes some patience and after walking the hammers around the joint the fitting will unthread easily. Most come apart in 5-10 minutes. The trick is not hitting it too hard, but just hard enough, you feel the backup hammer jump if you do it right.
  • Leonard
    Leonard Member Posts: 903
    edited February 2018
    Likely hard to do on large fittings. But a propane/air turbo torch works nice on car rusted nuts, dull red. Used 3 of them on a car exhaust sensor once. For larger stuff used ~ 50k BTU propane/air ice melting touch..... outside.

    Oxy-acetylened a car cast iron exhaust manifold yellow/white hot to remove badly rusted studs, rusted to toothpick diameter hourglass shape. Wet rag on stick applied to stud for max temp difference, watch the steam. But I needed to re-use the manifold
  • HVACguyinME
    HVACguyinME Member Posts: 25
    If I can’t get it with a pipe wrench, then I use a sawzall cut pipe off clean then make three cuts inside just barely cutting into threads. Then use chisel and hammer. This works great especially if you have to thread something back in. You will have to use tape and dope though.
  • StingerIII
    StingerIII Member Posts: 3
    edited January 24
    During the first half of my working life I was a millwright and we often used dry ice on one side to rapidly cool large stuck parts. Just for the heck of it I'm planning to try CRC Freeze-Off on four 38 year old copper fittings to see how that works. Their ad says that it instantly cools to -60F. Would be really cool if it works!
  • mattmia2
    mattmia2 Member Posts: 9,962
    38 years isn't very long and copper doesn't usually seize...