# DIY Carbon Fiber Frame Repair



## namdoogttam (Jul 1, 2014)

I recently fixed my own cracked carbon fiber mountain bike frame and, since I know there are a lot of aging carbon fiber frames out there, I thought I'd post my experience here, in case it's helpful to anyone else.

1) the Greasy Mouse: Carbon Fiber Mountain Bike Frame Repair.
2) the Greasy Mouse: Stumpjumper Carbon Fiber Frame Repair
3) the Greasy Mouse: Finishing Up! - my Stumpjumper Carbon Frame Repair

Disclaimers
- I went into this job pretty ignorant, and came out just as ignorant.
- I had no idea what I was doing and still don't, but my repair job hasn't broken yet.
- If you try to fix your own carbon fiber frame it could kill you, but YOLO, right?


----------



## mtnbiker4life (Sep 19, 2005)

I have a number of years designing carbon fiber components for a well known defense contractor......battle damage repair is a science in itself. Almost more complicated then the original layup because what you're trying to do is restore that damaged area to the original strength. We use to use ultrasonic testing to detect voids and defects......this process would tell you to extent of your damage and you repair plan.

I do commend you for taking the chance..............I would never do it but I've seen carbon failures and it scares the crap out of me. Plus I like my teeth


----------



## ithacking (Oct 15, 2012)

Ehmmm - ducktape.


----------



## cadoretteboat (Aug 27, 2011)

And Ty-rap, of course.


----------



## Diesel~ (Feb 17, 2008)

Cool project. Let us know how it holds up over time.

-D


----------



## namdoogttam (Jul 1, 2014)

Diesel~ said:


> Cool project. Let us know how it holds up over time.


It's still holding strong. I've been abusing this bike all summer, riding with abandon, racing, and still no issues. I'm fairly confident that the repaired area is stronger than the original frame (which many will contest is a liability...arguably putting additional stress on other parts of the rear triangle), but I have had zero issues thus far.


----------



## nickcube (Jul 25, 2012)

A bit of a dig, but how's it holding up? Cracked up my seat stay real good in a race today and i've seen the method around a bit


----------



## namdoogttam (Jul 1, 2014)

My repair now has two full seasons of constant use under its belt, including a good number of XC races, and it's performing like new. This has been my only mountain bike the whole time and I typically ride multiple times a week, whenever weather permits. 

Some of my favorite local trails are steep, rocky, and rugged and they definitely call for more of a trail/enduro bike. But this rig, with its repaired chain stay, has held up to all the abuse I could throw at it.


----------



## ljracer (Nov 6, 2009)

nickcube said:


> A bit of a dig, but how's it holding up? Cracked up my seat stay real good in a race today and i've seen the method around a bit


I've repaired a seat stay that had a clean break through it. The OP was very diligent and did a great job as shown in this thread! I was far less neat and mine has been holding up to abuse with no issues.

I followed carbon fishing rod repair videos on youtube using a wrap and compress method with drilled out electrical tape sticky side out to compress the wrap. 12 wraps total with a schedule of 4 wraps per layup. never let it fully cure between wraps for solid bond. I can see the repair area but I'm more confident that it's overbuilt. $10 kit off ebay was perfect.


----------



## Wacha Wacha Wacha (Sep 27, 2017)

Awesome! Thanks for the blog. I am going to use your "electrical tape as a peel-ply" method. Did you actually have resin seep through the tape? 

My thought is to use your perforated tape method then wrap a layer of paper towel around it to absorb the resin, then use shrink wrap and a heat gun to apply some pressure. I'll let you know how it goes.


----------



## D. Inoobinati (Aug 28, 2020)

*Member has removed content due to fundamental disagreement with this site owner's views favoring expanded access for electric mountain bikes (eMtb) on multiuse singletrack in public lands.*


----------



## Cleared2land (Aug 31, 2012)

Looks like a good job done on the repair. Impressive. What happened to the drop out?


----------

