Cracked chain stay- Mtbr.com
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  1. #1
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    Cracked chain stay

    So I've been asked to repair a frame for a friend.
    This isn't a should it be repaired question... it's getting repaired.
    My question is how. The frame is a 4130 single speed and the crack seems to have started from the tire clearance dimpling in the non drive chain stay. I have access to oxy accetelene or tig. Easiest option I think it to drill the ends of the crack and tig it. Option two is to make a bow tie /dog bone shaped gusset and braze that over the top of the crack. I feel option two is probably the best way for a longer lived repair. But I thought I'd open myself up to some general burning at the stake via Internet forum. thanks Pete.

  2. #2
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    Replace the tube?

  3. #3
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    Quote Originally Posted by Peter Jefcoate View Post
    But I thought I'd open myself up to some general burning at the stake via Internet forum.
    You've come to the right place!


    But ya, like brider said, replace the chainstay. The repair options you propose never seem to work as a long term solution.


    Who dimples a NDS chainstay?
    "Things that are complex are not useful, Things that are useful are simple."
    Mikhail Kalashnikov

  4. #4
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    Replace. Generally speaking, if you can't find a suitable replacement, replace them both.
    I ncredibly
    M yopic
    B ackstabbing
    A ssholes

  5. #5
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    Iíve no idea whatís best! You got any pictures?

  6. #6
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    Like others have said, replacing the CS would be the best solution. I don't think you need to drill the ends of the crack. Just tig weld a little beyond where it's visible. Chances of that lasting long term are low, but you could just braze a gusset over the top of the tig weld and that might fairly well. Careful how your gusset is shaped though, because it's going to cause stress risers.

    Have fun!
    Myth Cycles handbuilt bike frames
    Durango, CO
    http://www.mythcycles.com

  7. #7
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    Option #1 Tig weld it and overlap it with suitable metal.
    Option #2 Braze same method

    Do you Tig weld better then you braze, because brazing is a friggin art form.

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