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Leak in 3\" Steel

50 year old 3" steel pipe carrying 15 psi steam from a boiler has a hole in the top of the pipe. Hole is about 4"x2". It was patched years ago and the patch just blew out. The pipe is situated below the first floor and is barely above the dirt so getting underneath the pipe is not possible. The pipe is so old that I do not think I can unscrew it at the nearest union. I have tried covering the pipe with soil seal, wrapping the pipe with 10" wide aluminum flashing, and tightening the wrap with 5 plumbing bands. When the boiler was turned on, the soil seal was pushed out of the seams and it leaked. I tried putting bondo at the seams, but it still leaked. I am now wondering if there is a coupling I can use to patch this. I have seen clamshell type plumbing couplings with rubber inside. However, I am concerned the steam would melt the rubber. Any suggestions, I have worked on this for 2 days and can not figure it out.


  • Kevin Pulver
    Kevin Pulver Member Posts: 67
    It's late Matt

    But I'll try to brainstorm a bit...
    Portable welder to put a better patch on?
    Cut out bad section and use some sort of metal clamps to replace?
    It might not be the best solution, but I can't imagine the steam having enough pressure to blow out the type of compression patch you speak of. Nor could I imagine it melting the rubber, though it might deteriorate it?
    Did I see pictures of Mad Dog's one pipe steam using some sort of wide stainless bands/clamps to join pipe?
    Someone with more experience will give you better advice I hope. Kevin
  • Matt in Ohio
    Matt in Ohio Member Posts: 2

    I started using google to find some answers and stumbled on a product called Stop It Pipe Repair System. It says it can withstand up to 400 psi, I'm only pushing 15 psi. The temperature is up to 250 continuously with 500 on intermittent flow. I'm not sure what the temperature of steam is in a boiler. I looked up the temperature of a pressure cooker at 15 psi and someone said it was 252. I know water boils at 212, so this sounds reasonable. Does anyone have any experience with this product?
  • hot_rod
    hot_rod Member Posts: 21,880
    Sounds like the pipe needs to be replaced?

    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • ed_46
    ed_46 Member Posts: 11

    you need a welder to make and weld a patch in place
  • welder

    If you get a good welder he will be able to repair. Cut the pipe out that is damaged and with a band saw cut the pipe down the middle six inches from each side on both ends. When you put the pipe in place you will have a section of pipe on the top where you can see in. A good pipe welder will be able to weld the pipe from the inside and then weld the cut out section back into place after they are done. We have donne this will cooling lines that were to close to the roofand the welder couldnt get his rod under the pipe. It will work but may take several hours.
  • ttekushan_3
    ttekushan_3 Member Posts: 958
    I agree that welding is the best option

    but second best might be one of those big Desser Couplings with the bolts that draw, tighten and reinforce. You'd have to cut the pipe of course, and the Dresser couplings of that style and size are not cheap. I really don't know how this would compare to the price of welding.

    Just a thought.

  • dave_21
    dave_21 Member Posts: 6

    call in a welder, cut out section of pipe as much as possible, get him to weld 2 slip-on flanges.It will be easier to weld these on the inside as it sounds as if he wont have the room to weld all the away around the outside.then get him to make up a spool piece and then flange everything together.
This discussion has been closed.