# Carbon clearcoat scratch



## brblue (Jan 28, 2003)

The celarcoat on my Giant carbon fork is scratched (5 mm long, about 2 mm wide, .25 mm deep or less) I'm guite sure it's a surface scratch, it probably came from small stones being propelled by a passing car (other than that no crash, bike not leaned against anything etc.) Seems like the clearcoat has been removed on the entire length of the scratch

My questions are: 
- Can such a scratch trigger any kind of future failure of the fork? Like carbon fiber getting chemically "damaged" if "exposed". 
- How can one avoid such damage? I presume something like this is unavoidable if the bike gets ridden. My old aluminum fork got quite a lot of surface scratches in the 5 years used, but the fork being metal, I didn't worry about it that much. Just a slight cosmetical disadvantage.

Thank you,
br


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## arcspin (May 5, 2007)

I can add a question on the same topic.
How to refill the scratch, is there a clear coat that one can use to "paint" over the scratch and how will the result be?
Can you make such a scratch "vanish" from the frame/fork?


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## C-40 (Feb 4, 2004)

*fix it...*

Clean the area with some acetone or lacquer thinner and apply some clear nail polish. If you want a perfect repair, then several coats will be required, followed by careful sanding with 1000 grit sandpaper and final polishing with an automotive polish. 

A scratch like you've decribed will not propagate into a crack.

There's no way to prevent scratches, if they are from road debris, other than applying clear vinyl "frame saver" tape.


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## HammerTime-TheOriginal (Mar 29, 2006)

Will any clear nail polish do, or do some of them have some chemicals in them which could possibly damage the carbon fiber?


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## C-40 (Feb 4, 2004)

*any will work...*



HammerTime-TheOriginal said:


> Will any clear nail polish do, or do some of them have some chemicals in them which could possibly damage the carbon fiber?


All nail polishes are some type of acrylic lacquer. "Carbon fiber" is a composite of epoxy resin with carbon fiber reinforcement. Epoxy can be painted with any type of paint.


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## MANTEIGA (Sep 26, 2008)

*no worries......*

Carbon fiber is strong as hell.

I shattered a Madone seat mast due to overtightening and replaced it.
It was great cause i used the old mast to conduct some integrity tests on
treks OCLV.....

After multiple impact, sawing, scratching, crushing, heating, etc. tests i was able to confirm that, carbon fiber is one strong m#$ther f&%ker!!! 

The paint on a Trek Madone is thick and pretty strong, but under a strong enough impact, 
the clearcoat will chip off....
If you hit the surface hard enough, you will rip through the aprox. 1mm of paint and you will know when you do. ( naked carbon is very shinny and light to med grey. It doesnt't look anything like paint. ) 

Anyway, if you manage to get this far, you would need a collision type impact to do damage. CF is way stronger than metal and will flex HUGE distances before snaping.
However, just like diamonds, Carbon will break if the impact is strong enough - mixed with colliding with a hard enough substance and impacting with enough force.

Tap test your frame. If it sounds strange than have it sent back to the manufacturer.

Carbon will burst into flames if it suddenly fails. (just kidding) 
But it still could crack if it;s damaged internally.

hope this helps. :thumbsup:


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## RobsWheels (Feb 12, 2021)

MANTEIGA said:


> *no worries......*
> 
> Carbon fiber is strong as hell.
> 
> ...


Burst into flames. Good one. 🤣


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## cxwrench (Nov 9, 2004)

RobsWheels said:


> Burst into flames. Good one. 🤣


It was...in September of 2008.


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## Lombard (May 8, 2014)

cxwrench said:


> It was...in September of 2008.


Nothing like a good thread dredge. Almost as satisfying as a 20 inch poop.


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## DrSmile (Jul 22, 2006)

I have children younger than this thread in middle school.


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