I am new here and was wondering what sort of home carbon repair kits there are out there and which ones work best. I have a small crack on my top tube and I wanted to see if I could save a bit of money by doing it myself. It's just raw carbon with clear coat so I don't need to do any sort of paint matching. Any suggestions would be great and if I find something that looks good I will post it up here for other people that might be interested. Thank you in advance.

I haven't heard anything about do it yourself carbon repair. In fact, I have read that it takes a pro to even tell whether carbon is damaged or not in some cases where damage isn't even visible. Therefore, I would think a carbon repair at home would need to be done very carefully (if at all).

However, I would ask in the Frame Builder's forum since some of them may make their own carbon frames, so may have a handle on what supplies are available.

Like this
and this

kit? you got the vacuum bagging concept down ? the wet epoxy mix saturated cloth is de bubbled while the epoxy cures . in a plastic bag around the patch
which is hooked up to a vacuum pump..

maybe you can do good enough pushing bubbles out with your neoprene rubber gloved hands..


already used to working in fiberglass ?, it should be pretty transferrable..


Vacuum Bagging Basics

I've seen industrial references (not bicycle-related) that plainly state that if a composite part fractures, it's ruined and should be replaced. There is no way to effectively repair it.

The strength of a composite material depends on the fiber length, and when you get a fracture a lot of the fibers at that point are already broken. Filling in the crack with "micro fiber epoxy" will unfortunately only give you "micro strength", due to the short fiber length of "micro fibers". There is no practical way to integrate NEW long fibers into the matrix of existing epoxy+fibers around the broken area.

Saying "it's just as good" is totally wrong: if it was, the manufacturer would have made the whole frame out of micro-fiber epoxy in the first place. That would be far easier than wetting and laying directional fibers, and yet no CF bike frame company does that.

My non-biking friend is a liaison engineer with Boeing. According to him, they are constantly repairing dings and cracks in the carbon aircraft caused by accidents during assembly. They mostly use pre-preg and scarf it in.

Tell these guys:
https://calfeedesign.com/repair/

I've done a repair on my wife madone 6.. the seat post area developed a vertical crack .. one layer outside.. another layer inside.. sanded down the outside layer so the seat mast just fits.. so far so good. The seat mast covers 95% of the repaired area.. so no biggie.

Just throw some duct tape over it, good to go.

Most frames from decent companies will have a lifetime warranty.
Chinarellos won't.

If you want it to look good, you'll probably have to send it somewhere. Or you can throw a patch on it and ride it ugly. If you patch yourself, make sure you use sufficient thickness to account for the fact that you have NO thickness right now at the crack.

Calfee is the standard "go to" recommendation, but if you're in a major market, there is a good chance you'll find someone local who can do it for you as well. Generally, if you can find someone local to do it for you, a cosmetic repair will cost you around $300 or so.

I have done hundreds of carbon repairs in the past, no problems. But when my own wife's bike needed repair I sent it to Calfee.

I believe Pre Preg is Heat activated and still Vacuum Bagged to get it to bond without Void Bubbles

But of course for Boeing that is as simple as a Band aide because they have the Equipment to heat those patches and suck the air out.

Thank you everybody for the responses! You have been very helpful.

I just bought this repair kit on Amazon and it worked great! I was able to watch a few videos on youtube to get a better understanding on how to fix my frame ( I had a small top tube crack ). Here is the link for anybody that might find use for this. It was 75 dollars and if I would have sent this to a carbon repair place like Predator or Calfee it would have cost me between 150 and 250 just for the repair plus shipping.

https://www.amazon.com/CyclingSale-Bi...+carbon+repair

All you need is this.

FWIW: Saw this stuff at Lowes the other day. https://www.fiberfix.com/gallery/sport-and-outdoors/ , not that I'd recommend it.