Why is there discoloration in my carbon fiber?

You just received your new Anvil Auto carbon fiber or carbon fiber / fiberglass parts and are wondering how to prevent any discoloration in your parts. Unfortunately, discoloration is an inevitable process, but can be delayed if you choose to leave the carbon fiber exposed. 

Why will my parts discolor over time?

Our composite parts are made with epoxy resin that contain UV stabilizers, which ensures the discoloration process is delayed for a long time. On top of that, our parts are also cleared with a UV clear coat to further delay the discoloration process. This ensures there will be no discoloration for a long time if you choose to leave the carbon fiber exposed and the parts are well maintained. The following common reasons are why you may start seeing some discoloration; these are not exclusive to our parts, but for all composites across the board.

UV Light

Exposure to UV light is the most common reason for composites to discolor. When UV light hits the epoxy resin, whether it be directly or indirectly, the natural process of degrading the polymers in the epoxy resin is sped up. This reaction is responsible for more than just turning the epoxy resin yellow, it also causes delamination, cracking, and chalking in the coating. This process can happen in just a matter of months if proper care is not followed.

Extreme Heat

Long, continuous exposure to high temperatures can cause discoloration in epoxy resin. However, this is the least likely cause of discoloration in the majority of cases.


Exposure to moisture can lead to delamination and cracking if moisture finds its way into the epoxy resin through cracks, chips, or pinholes. In some instances it can lead to discoloration.  


In this case, discoloration begins with the hardener used to cure the epoxy resin and not the epoxy resin itself. Oxidation turns the hardener yellow over time. This happens immediately when the hardener is opened for the first time and is applied to the epoxy resin.

What can I do?

Although exposed carbon fiber parts will eventually show signs of discoloration, there are some steps you can take to ensure this will not happen for a long time.

 It is very important to limit the amount of exposure to UV light and extreme heat. If your parts are installed on your car, store your car out of the sun's reach and in a cool location. 

If you have parts in the engine bay or a hood, open the hood to allow heat to escape. 

If you see any kind of cracks, chips, or pinhole in any of your parts, it is very important to have the area repaired as soon as possible to prevent moisture from getting in. 

Applying a wax or ceramic coat, just like on the paint of your car, can aid in delaying the declaration process as well.

Following these preventative measure help in maintaining the carbon fiber, ensuring you can enjoy the look of it for a long time.    

1 comment

  • Sam Andrews

    Oh, okay. The idea that any auto part made of carbon fiber could last longer when we protect it from excessive humidity sounds fantastic to me. My son keeps thinking of upgrading his car part before winter arrives. I truly believe he’ll get the best result by visiting an auto detailing shop quickly. https://xotixcars.com/shop/ols/products/lamborghini-urus-carbon-package-bumper-mirror-cover-fender-bumper-cover

Leave a comment