Repairing chipped Carbon Fibre frame

ahbtsang

Hi all,

I was cycling last week and unfortunately my chain and rear mech broke off and smacked into my carbon frame chipped away a small portion of the paint. Now the black carbon is exposed to the outside.

I am wondering what is the best way to repair the chip? I've looked into car paint pens from Halfords, model paints for ABS plastic and resin for glass fibre. However, I'm worry that any of these materials may corrode the carbon fibre...

Any advice will be much appreciated.

Thanks a lot.

andrewjoseph

don't do anything until you've really researched it. there may be places in the uk that repair carbon, there seem to be a few in the US that do.

but it might be best to check that the frame is sound. I read somewhere that to test carbon has not delaminated, tap it around the area, if it sounds dull, there is a problem.

MattC59

Give this guy a call: http://www.carboncyclerepairs.co.uk/index.html

He did a cracking job on a damaged wheel of mine, you can't see the repair. I've also seen first hand his work on frames, it's extremely good. On top of that, he appears to have people queueing up for repairs.

ahbtsang

Thanks guys, so really necessary to have my frame checked even it is a small chip? Sounds like its gonna be a big expenses..

MattC59

It might not be as expensive as you think. If it turns out to be just a chip it won't cost you the earth. If you can, take the frame in there, but certainly give Darren a call to discuss the repair.

warrerj

ahbtsang wrote:

Thanks guys, so really necessary to have my frame checked even it is a small chip? Sounds like its gonna be a big expenses..

If it's just a chip in the paint then all you need to do is seal it with something. Depending how big the chip is you can do that with nail varnish, car paint or if it's a bigger chip a dab of araldite or other expoxy resin type glue.

Carbon really isn't as complicated as people think.

PS - I speak from 10 years experience of working with composites.

ahbtsang

Please have a look at the image, and give me some thoughts. I really think it isn't that big..

CalumR

If it was me I'd just get it checked over for piece of mind. I'd prefer to spend a few quid on that rather than it failing in the middle of a ride and having an off.

warrerj

It's hard to tell from a photo. It looks just cosmetic tba. The only way to know it to "have a feel". If it's soft or there's any give then it'll need looking at. Compare it to the other stay as a guide.

Just from the photo I'd say all it needs is a splash of paint BUT as above if you're really not happy get it looked at. nothing worse than not trusting your kit

rpd_steve

It does look cosmetic, but carbn can be increadibly deceptive - if it is just the matrix that has fractured then it may maintain form but have no strength or propogate at the next sign of shock. Seat stays are also in compression so small damage is moreimportant than if it was on a mamber in tension like a chain stay or down-tube. Its fair advice given above to do a tap test with a £1 coin - you will imediately hear the differance if there is aby damage.

If you really want you head put at rest then you can send it to us and I will have it ultrasounded in our composites dept - only £20 beer money for the NDT guy to do it at lunch. If it is ok we can easly touch the paint in and if its not the repair is not too steep either.

There is some pics on our website of a Bianchi we did recently that had a 1" chunk out of the downtube, mid repair, after sanding and after paint.

http://rpdmotorsport.com/gallery.php

Look though my previos posts as I've helped a few people with frame damage before. If you want any help then get in tough via the details on the website.

Monty Dog

Cosmetic damage IMO - don't see the need for anyone to look over it, particularly as the damage is on the joints which are massively over-engineered - people tend to be a bit neurotic about carbon, believing that one small chip will result in catastrophic failure. You can buy repair materials from carbonmods.co.uk

ahbtsang

thanks for everyone's input. I've sent the repair company a message and see what they says.

Also, to smoothen out the paint, can I apply epoxy resin for fibre glass instead of one specifically for carbon fibre? thts because glass fibre resin is more widely available.

warrerj

You can use epoxy hence my earlier commetn on araldite (it's just thick eposy in a tube). for that depth of chip you'd be just as well to build it up with paint or spray filler.

Headhuunter

ahbtsang wrote:

Please have a look at the image, and give me some thoughts. I really think it isn't that big..

I've got various bashes and gashes in my Focus carbon frame. One of them was caused a few years back when the head of the hammer I was using flew off the handle and slammed into the bike frame (of all the things behind me it could've hit, it hit the bike...), the gash is a bit like the ones you have, although smaller and it's been there for about 2 years...