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How repair cast iron radiator spitting steam

bruce_21 Member Posts: 241
My client has two (of 12) cast iron radiators that have pin leaks in the tubes.

Is it possible to clean them (like with a disk sander or something to get down to bare metal) and then put an epoxy putty like PC-7 or JB Weld or? to seal the leak? Will this idea work? or what else can be done?


  • Patrick_North
    Patrick_North Member Posts: 249

    I've used an expoy put out by Locktite for this purpose to good effect. Just make sure it's approved for high temps.The operating pressure should be good and low, so it's not as if you're holding back torrents of steam- just a few ounces.

    Good luck,

  • leaky rads

    maybe a drill, and tap followed by machine screws would close the holes--nbc
  • Jean-David Beyer
    Jean-David Beyer Member Posts: 2,666
    maybe a drill, and tap

    I thought of that. But I am not a professional and have no experience drilling cast iron. Can you drill cast iron, or does it crack and chip when you attempt that? Similarly with tapping. I have had bad experience drilling some castings, but they were probably pot metal and not regular cast iron.
  • Big-Al_2
    Big-Al_2 Member Posts: 263

    JB-Weld has polyamide resin in it in addition to epoxy.  That should make it more stable at higher temperatures.  I've used it succesfully on two steam radiators.   One had a weepage around a threaded nipple between sections, and another one was cracked. Both patches held.  (I replaced the cracked one over the summer.).  If you have a pinhole, you might be successful with a JB-Weld scab over it, but if it turns out to be a crack, it will probably grow and come out from under the patch.
  • Jean-David Beyer
    Jean-David Beyer Member Posts: 2,666
    growing cracks

    What is sometimes done to prevent cracks from growing is to drill a hole at each end of the crack, at the extreme end. The hole, being of greater diameter than the crack line, distributes the stress over a larger area, and this is less than the shear stress of the metal. At least, that is the hope. I notice this most in airplane wings. I do not know if it is worth persuing in radiators.
  • Big-Al_2
    Big-Al_2 Member Posts: 263
    Holes to Stop Cracks

    Yes, drilling holes to stop cracks could work very well on a radiator . . . providing:

    A) You can actually find the true end of the crack.


    B) You can reach that spot with a drill.

    Either one could be a challenge.
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