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-   -   carbon frame repair (http://www.bikeforums.net/framebuilders/931190-carbon-frame-repair.html)

zacster 01-23-14 07:17 PM

carbon frame repair
 
I've been building wheels the last 2 weeks and using my ever so slightly cracked Kuota Kharma frame and fork as a truing stand. I had a hard almost straight on crash when the bike was still fairly new 9 years ago. The cracks appear at the internal lugs between the steerer tube and both the top and down tube. The fork is definitely toast as the steerer shattered. So, looking at my very expensive truing stand I started thinking if this was fixable. I've heard that Calfee does this? Not sure on that. But could this be repaired? And how much would it cost?

I replaced this frame with a Kuota Kredo the next year when my wrists healed (yea, they BOTH broke in the crash) and transferred all the parts. So it is basically a bare frame without much else to salvage so it wouldn't be a cheap rebuild. I really preferred the ride of the Kharma over the Kredo, even though the Kredo was the more expensive frame. I could ride the Kharma all day long every day without feeling it.

Andrew R Stewart 01-23-14 09:16 PM

I have always (well as I began to understand carbon as a structural material) felt that good design with it is a level higher then with metals. The directional strength and matrix aspects combine to make carbon a different animal.

So in reading your question i think of Craig's 30+ years of working with the stuff and all he has learned. I would not want to try to repair a steerer that had shattered. I wonder if Calfee would. As to the frame I would take a number of good photos and contact a repair shop (like Calfee) and see what they say. Like many situations the basic materials are not very costly but the skills are priceless. Andy.

MassiveD 01-26-14 04:30 PM

Probably no big deal to fix. A lot of people get all gooey over fixing a carbon bike, we even had a good fight over it being impossible to do, yet every kid on the block is making a bamboo bike. Sometimes they are putting it together with hemp, let along glass or carbon.

Two things. It isn't going to be pretty. You can fix a steel bike so that it is as good as new, and I guess one could do the same with carbon but at the cost of doing a fairly complete rebuilt from scratch. A rebuild will be adhered not bonded, so it will need the kind of build up a bamboo bike needs. The other thing is that it is pretty hard to do in areas where you run out of space. Saw a tube apart in the middle, no problem to patch it, you have 10 inches either side. But if you don't have a lot of space it could ger tougher to do. I wouldn't bother.

zacster 01-27-14 04:06 AM

I would probably never do it either, but I was curious. I could probably buy a complete no-name carbon bike for less than the cost of the repair.

Mark Kelly 01-27-14 06:31 AM

Quote:

Originally Posted by MassiveD (Post 16442452)
A rebuild will be adhered not bonded..

Curious to know what you mean by this.

Canaboo 01-27-14 12:12 PM

I'm sure he means a mechanical bond versus a chemical bond. Just the way Epoxy works depending on the stage of cure it is at.
After doing a lot of work with carbon and doing several repairs I'm convinced that practically any damage can be repaired.
Even though a repair is often very noticeable as far as not matching the rest of the weave it can still look reasonable as far as being a "scar" goes.


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