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  1. #1
    pluralis majestatis redfooj's Avatar
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    Is this concerning damage on a CF MTB frame?

    2010 Trek Elite CF Frame
    Bottom of BB got nicked on a rock... owner filled gouge with JB Weld and then taped over



    doesnt look deep but is in a stress-sensitive area. do you think it will hold up?

  2. #2
    Old School Rad mtnbiker66's Avatar
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    You can fix anything with JB Weld and some tape....... Throw in a mountain dew can and you can save the world. I had a friend that rode a carbon bike with a lot bigger gouge than that with no issues........but I have no clue about carbon bikes so someone else will need to answer this for ya.
    Like a circus monkey on a stolen Harley......

  3. #3
    In search of moar cowbell dminor's Avatar
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    With a JB Weld job, if you don't wave a black light over it for the first 5 minutes of catalytic reaction, the aluminum particles will not properly grain-align - - something that is crucial to patching CF. The only way to determine now if there was proper grain-alignment is with a Zyglo scan.

  4. #4
    Old School Rad mtnbiker66's Avatar
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    Quote Originally Posted by dminor View Post
    With a JB Weld job, if you don't wave a black light over it for the first 5 minutes of catalytic reaction, the aluminum particles will not properly grain-align - - something that is crucial to patching CF. The only way to determine now if there was proper grain-alignment is with a Zyglo scan.
    ....and I guess you could do that for a fee?
    Last edited by mtnbiker66; 09-24-12 at 12:17 PM. Reason: spelling
    Like a circus monkey on a stolen Harley......

  5. #5
    Frozen in carbonite Grimlock's Avatar
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    It depends on what type of rock he hit in the first place. The JB Weld can over-catalyze if it was a sedimentary or igneous rock. If that was the case, I'd strongly suggest media-blasting (with ball bearings) the bottom bracket to remove the JBW. Once you've ball-burnished the BB with BBs, be careful to rub a little mineral oil from your XT levers on the affected area. You want to break in the break in the clearcoat with brake fluid, lest it break while you're braking. If it breaks, you'd be broke.

    Tl;dr It's fine.
    Quote Originally Posted by sp00ki View Post
    Using a nicer sealed bearing headset vs a $10 set is like throwing a frisbee vs a dodgeball.

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