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  1. #1
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    Steel chainstay repair?

    Hello all,
    Iím a newbie here and have a question. I am trying to restore a Ď91 Kona Cindercone. The right chainstay has been worn rather thin due to chain rub. The effected area is about 1Ē long. Is this better left alone or is it possible or conventional to lay some brass down in this area? Or is this likely to do more harm than good? My welding / brazing skills are well above average.
    Thanks all.
    Glen G
    Attached Thumbnails Attached Thumbnails Steel chainstay repair?-72b8dfe0-0cbd-4a3b-afc3-4e2668c6bd92.jpg  

    Last edited by glen gardner; 09-29-2018 at 10:10 PM.

  2. #2
    CS2
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    I have to believe welding is stronger than brazing for what you want. But thatís a whole lot of heat to apply to thin wall tubes.
    A garage full of steel frames means happiness.

  3. #3
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    Quote Originally Posted by CS2 View Post
    I have to believe welding is stronger than brazing for what you want. But thatís a whole lot of heat to apply to thin wall tubes.
    Understood. But I'm a competent TIG welder. I could dial down heat and lay silicon bronze filler to build up and reinforce this area. I want to ride this bike without fear of structural failure so I am trying to find out what the general wisdom is on this sort of damage /repair. Is this frame a total loss or can it be returned to safe rideable condition?

    -G

  4. #4
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    If you think the chainsuck is pretty deep and has really weakened the tube, you could silver braze a steel patch over the top. That's low heat would really beef up that area.

  5. #5
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    Thanks DC,
    A slight pressure with an allen wrench created an ovaloid concavity about 1" long. Not too deep, maybe .005" but this makes me think the tube is quite thin in this area. If i try to fit a patch over this area I worry it will not be absolutely flush to the tube and that silver brazing would result in a void under the patch? Silicon bronze filler rod is considerably stronger than brass or silver. I lays down on steel very nicely with TIG, and without a huge heat input. I figure I have one shot at this repair.
    -G

  6. #6
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    Quote Originally Posted by glen gardner View Post
    Thanks DC,
    A slight pressure with an allen wrench created an ovaloid concavity about 1" long. Not too deep, maybe .005" but this makes me think the tube is quite thin in this area. If i try to fit a patch over this area I worry it will not be absolutely flush to the tube and that silver brazing would result in a void under the patch? Silicon bronze filler rod is considerably stronger than brass or silver. I lays down on steel very nicely with TIG, and without a huge heat input. I figure I have one shot at this repair.
    -G
    True. Silver could flow right through and its strength rolls off really quickly above gaps of 0.005". I would worry too much about a void in the middle of the patch as long as you get good penetration around the perimeter. That would be sort of like patching a hole in your tube. But you will need to get it a lot hotter brass/bronze.

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