My road bike is aluminum with a carbon rear triangle. The carbon rear slides into the aluminum, and I believe was bonded with some sort of epoxy. The pieces have begun to separate after 2.5 years and the company will not warranty the frame.

Is it possible to repair this by inserting epoxy into the gap and sliding the carbon back in place? What sort of precautions should I take, and epoxy should I use?

If I can pull the carbon out further, should I sand the two surfaces before re-bonding?

  • possible duplicate of Fixing Carbon Fiber
    – joelmdev
    Sep 26, 2013 at 22:27
  • It's a good question, but it's a duplicate. Don't do it yourself. Call Calfee.
    – joelmdev
    Sep 26, 2013 at 22:28
  • If I attempted this (which I might because I'm kind of a DIY guy), I'd reenforce the joint with a carbon or fiberglass wrap, vs just relying on epoxy. Sep 26, 2013 at 22:40
  • Catastrophic frame failure due to poorly informed DIY? No thanks. Sep 27, 2013 at 2:09
  • 3
    The linked possible duplicate is about fixing a hole in carbon. This question is about bonding carbon to aluminum. They appear to me to be two different questions.
    – jimchristie
    Sep 28, 2013 at 17:29

1 Answer 1


I am posting this as an answer but it is more of a long comment. The information I have is from the place I trust to do carbon repairs. According to Hot Tubes aluminum and the carbon resin react. The aluminum must be sealed to get a good bond. The materials are not your hardware grade epoxy. If we were talking about a fishing rod or something that would not cause serious injury in the event of failure I would say go for and try to fix it yourself. My thought is there is enough information and the resulting horror stories of catastrophic frame/component failure to warrant at least getting a professional opinion.

  • Yeah, no kidding. Sep 27, 2013 at 2:08
  • Seconded. There's a good chance that some fancy proprietary epoxy is used. Good luck acquiring that at a hardware store. There's also the fact that the gluing itself may require special tools, techniques, and conditions. Seconding staying far away from a DIY solution.
    – moshbear
    Sep 27, 2013 at 12:17
  • 1
    I took this advice and found a place in town (brokencarbon.com) to do the repair. It was worth it (for peace of mind) to not fix it myself, the repair was pretty cheap and comes with a 5-yr warranty.
    – mrsoltys
    Oct 8, 2013 at 1:31
  • 1
    @mrsoltys Good work - a 5 year warranty is longer than the frame maker's warranty! So, after ~2 years how is it holding up ?
    – Criggie
    Nov 25, 2015 at 8:40

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