Carbon Fiber Yellowing – Effective Solutions for Restoration

Carbon fiber is a lightweight, strong material used in various applications, such as automotive parts and sporting equipment.

However, one downside to carbon fiber is that it can begin to yellow and deteriorate if not properly protected.

This yellowing of carbon fiber is caused by exposure to harmful UV rays which can break down the material’s clear finish.

It’s essential to both prevent and address carbon fiber yellowing to maintain its aesthetic and structural integrity.

Carbon Fiber Yellowing

Understanding the causes and impact of carbon fiber yellowing is crucial in preventing its damage.

The key is to regularly inspect your carbon fiber parts for any signs of fading or yellowing.

Once identified, you can then take the necessary steps to restore and protect your carbon fiber from further deterioration.

Key Takeaways

  • Carbon fiber yellowing occurs due to UV exposure, causing aesthetic and structural damage
  • Regularly inspect your carbon fiber parts to identify and address signs of yellowing early on
  • Prevention and restoration efforts are essential to maintaining the long-term durability of carbon fiber components

Where Is Carbon Fiber Used In Cars?

Carbon fiber is used in various parts of cars due to its high strength-to-weight ratio, rigidity, and corrosion resistance. Here are some of the common parts and areas where carbon fiber is used in cars:

Body Panels: Carbon fiber can be used for exterior body panels such as hoods, roofs, trunk lids, and fenders. It not only reduces the weight of the car but also provides a unique aesthetic appeal.

Chassis and Monocoque: Some high-performance cars and supercars use carbon fiber for their entire chassis or monocoque structure. This provides a lightweight yet extremely rigid structure, which is crucial for handling and performance.

Interior Components: Carbon fiber is often used in the interior of cars for parts like dashboard inserts, center consoles, door panels, and seat frames. It provides a sporty and premium look to the interior.

Wheels: Some high-end cars and aftermarket wheel manufacturers offer carbon fiber wheels. These are lighter than traditional alloy wheels, which can reduce unsprung weight and improve handling.

Drive Shafts: Carbon fiber drive shafts are used in some performance cars because they are lighter and can handle high torque loads.

Spoilers and Aerodynamic Components: Carbon fiber is commonly used for making spoilers, diffusers, front splitters, and other aerodynamic components. These parts benefit from the lightweight and high-strength properties of carbon fiber.

Suspension Components: Some performance-oriented cars use carbon fiber for suspension arms or links to reduce weight.

Brake Components: Carbon-ceramic brakes, which are often used in high-performance cars, sometimes incorporate carbon fiber in their construction.

Engine Components: Parts like intake manifolds, valve covers, and even some structural components can be made from carbon fiber to save weight.

Exhaust Systems: Carbon fiber can be used for exhaust tips and even entire muffler systems in some high-end cars.

Racing Seats: Many racing seats are constructed using carbon fiber to achieve the desired strength while minimizing weight.

Battery Casings: In electric and hybrid vehicles, carbon fiber can be used to create lightweight and strong casings for batteries.

It’s worth noting that while carbon fiber offers many advantages, it is also more expensive than traditional materials like steel or aluminum.

As a result, its use is often reserved for high-performance, luxury, or specialty vehicles.

However, as manufacturing processes improve and costs come down, the use of carbon fiber in mainstream cars may become more widespread.

Understanding Yellowing of Carbon Fiber

Causes of Yellowing

Both UV and heat play a significant role in the yellowing of carbon fiber. Here’s how:

UV Light: When UV light hits the epoxy resin, it speeds up the natural degradation process of the polymer, causing it to yellow. This reaction can also lead to delamination in the resin, further impacting its appearance and integrity.

Heat: Sustained high temperatures can cause the oxidation of the carbonyl-group in the resin, which also turns yellow.

Note that both of these are normal chemical reactions.

To prevent or minimize these effects on your carbon fiber, consider using UV-resistant epoxy resin, as it helps provide added protection.

Remember to regularly maintain and check your carbon fiber components for yellowing and discoloration in order to address the issue promptly.

Impact of Yellowing Carbon Fiber

Effect on Strength and Weight

Yellowing carbon fiber can be concerning, especially if you’ve invested in this lightweight, strong material for its impressive properties.

However, you’ll be relieved to know that the yellowing effect is primarily due to the finish, not the carbon fiber itself.

The discoloration is caused by the clear coat or gel coat being exposed to heat and UV rays over time.

This means that although the appearance may be affected, the strength and weight of the carbon fiber typically remain unchanged.

Aesthetic Deterioration

While your carbon fiber’s strength and weight aren’t compromised by yellowing, the aesthetic value of the material certainly takes a hit.

A once glossy finish may appear dull and discolored, detracting from the overall look of your product or vehicle.

To address this issue, you can follow a few simple steps:

  1. Remove Surface Contamination: Clean the carbon fiber surface to eliminate any dirt, dust, or debris.
  2. Remove Faded Coat: Carefully sand away the old or discolored clear coat using fine-grit sandpaper.
  3. Fill Fissures or Chips: If any cracks or chips are present, fill them in with clear filler.
  4. Apply New Coat and Polish: Apply a fresh coat of UV-protected clear coat, then polish the surface until it regains its original shine.

By following this process, you can restore the appearance of your yellowed carbon fiber and enjoy its impressive qualities once more.

Inspection of Carbon Fiber Parts

Recognizing Damage

When inspecting your carbon fiber parts, it’s important to keep an eye out for any signs of damage.

Some common signs of damage to look for include:

  • Cracks: Hairline fissures or deep chips that may compromise the integrity of the carbon fiber surface.
  • Surface abnormalities: Old or deteriorated fibers may comprise the overall appearance.

By conducting regular inspections, you can identify damage early and take appropriate action.

Identifying Cloudiness and Fading

Carbon fiber parts, like a carbon fiber hood, can sometimes become cloudy and faded over time.

This can be due to various factors, such as oxidation or poor gelcoat with minimal UV inhibitors. To identify cloudiness and fading:

  1. Examine the surface closely for any signs of yellowing or dullness.
  2. Compare the affected area to a new or unaffected carbon fiber part to determine the extent of discoloration.

Once you’ve identified cloudiness or fading, take steps to restore and protect the carbon fiber.

This may include applying a high-quality clear coat or seeking professional help to reapply a protective layer.

Preventive Measures for Yellowing

Protection Against UV Damage

UV damage is a common cause of carbon fiber yellowing. To protect your carbon fiber components, apply a clear coat that offers UV resistance.

This will ensure that the epoxy resin used in the carbon fiber doesn’t deteriorate under sunlight exposure.

A high-quality clear coat can effectively guard against yellowing and enhance the appearance of the carbon fiber surface.

An alternative protection method is using a wax or paint sealant specifically designed for carbon fiber.

These products can also help in safeguarding against UV damage and maintain the pristine condition of your carbon fiber components.


Regular maintenance is crucial to keep your carbon fiber looking new and prevent yellowing. To maintain your carbon fiber components, follow these steps:

  1. Clean: Keep the carbon fiber surfaces clean by washing them with a mild soap and water solution. Rinse thoroughly and dry with a microfiber towel. Avoid harsh chemicals or abrasive materials.
  2. Inspect: Check the carbon fiber components regularly for signs of discoloration or damage. Early detection can help in addressing the issue promptly.
  3. Reapply: If you are using wax, paint sealant, or a clear coat protectant, reapply it as recommended by the manufacturer to ensure ongoing protection against UV damage.

By following these preventative measures, you can effectively reduce the risk of carbon fiber yellowing and maintain the appearance of your valuable components.

Remember, proper care and protection are key to keeping your carbon fiber looking its best.

Restoration of Yellowed Carbon Fiber

Old or Faded Coat Removal

To restore your yellowed carbon fiber, start by removing the old or faded clear coat.

You can do this by wet-sanding the surface with a fine-grit sandpaper, such as 1500 or 2000 grit, and using water as a lubricant.

Make sure to work in a well-ventilated area and take your time, so you don’t accidentally damage the underlying fiber.

Here are the necessary steps:

  • Wet-sand the surface using a circular motion
  • Keep the surface wet to prevent heat buildup
  • Rinse the surface frequently to remove residue

Applying New Coat

After you’ve removed the old or faded clear coat, it’s time to apply a new one.

The new clear coat can be either a high-quality automotive clear coat or a specially-designed epoxy resin for carbon fiber.

Before applying the new coat, make sure to clean the surface thoroughly and let it dry completely.

Then, apply the new coat in a thin, even layer, following the manufacturer’s instructions.

Allow it to dry and cure according to the recommended time before using or exposing your carbon fiber part.

Keep these things in mind:

  • Use a high-quality clear coat or epoxy resin
  • Follow the manufacturer’s instructions for application
  • Allow the coat to dry and cure before use

By properly removing the old or faded coat and applying a new one, you can restore your yellowed carbon fiber parts and extend their life.

Diagnosis of Advanced Yellowing

Identifying Severe Damage

When examining carbon fiber parts for yellowing, you should look for signs of severe damage such as cloudiness, deep chips, cracks, or fissures.

Over time, the clear resin that protects the carbon fiber can turn tan as it oxidizes, contributing to the yellowed appearance.

If the yellowing is accompanied by other signs of damage, it is likely that the clear coating has been compromised.

For example, cloudiness and deep chips may indicate that the clear coat has become damaged, allowing water and contaminants to penetrate the fibers.


If your carbon fiber part shows advanced signs of yellowing and damage, it may be necessary to replace the part altogether.

This is especially true if the yellowed area has turned into a series of cracks or fissures, which can compromise the structural integrity of the carbon fiber.

When considering replacement, be sure to weigh the pros and cons of having the damaged part replaced:


  • Restores the original appearance of the carbon fiber
  • Ensures the integrity of the part, maintaining its strength and durability
  • Prevents further damage and oxidation


  • Can be expensive, especially for larger or more complex carbon fiber parts
  • May not fully restore the part’s original appearance if the damage is too severe

In conclusion, when diagnosing advanced yellowing in carbon fiber, it is crucial to identify the extent of the damage and decide whether or not a replacement is necessary.

By carefully examining your carbon fiber part for signs of yellowing and additional damage, you can make an informed decision about the best course of action to restore its appearance and maintain its strength.

Frequently Asked Questions

How can I fix yellowing carbon fiber?

To fix yellowing carbon fiber, you can try buffing it out if the damage is not too severe.

However, if buffing does not help, you may need to seek professional help for a more thorough solution.

In some cases, a clear coat or sealant with UV protection may be needed to prevent further yellowing.

What causes carbon fiber to turn yellow?

Yellowing in carbon fiber is mainly caused by UV exposure and oxidation.

Epoxy in the carbon fiber can degrade with time, leading to discoloration and loss of mechanical properties.

It is crucial to protect the carbon fiber from these environmental factors to maintain its appearance and performance.

Is it possible to recoat carbon fiber?

Yes, it is possible to recoat carbon fiber, especially if it is showing signs of yellowing or damage.

Seek professional help to ensure the proper application of an appropriate clear coat or sealant that offers UV protection.

This will help protect the carbon fiber from further damage and fading.

Does sunlight cause carbon fiber yellowing?

Sunlight, particularly its UV rays, can cause yellowing in carbon fiber.

Exposure to UV radiation degrades the epoxy in the carbon fiber, resulting in yellowing and loss of performance.

To prevent this from happening, use a clear coat or sealant with UV protection to shield the carbon fiber from harmful sun exposure.

How can I repair a discolored carbon fiber roof?

To repair a discolored carbon fiber roof, start by cleaning the surface thoroughly.

If the yellowing is only mild, try buffing the surface to restore the original color.

In more severe cases, you may need to apply a clear coat or sealant with UV protection to prevent further discoloration and protect the roof from environmental factors.

What are the best methods for carbon fiber gel coat repair?

Here are some methods for carbon fiber gel coat repair:

  • Clean the surface thoroughly and sand it down to remove any damaged or yellowed areas.
  • Apply a high-quality gel coat that matches the color of your carbon fiber component.
  • After the gel coat cures, wet-sand the surface to gain a smooth finish.
  • Apply a clear coat or sealant with UV protection to cover the repaired area and protect it from further damage.


Carbon fiber, renowned for its lightweight and robust properties, has become an integral material in various applications, from automotive components to sporting equipment.

However, its susceptibility to yellowing due to UV exposure and oxidation poses challenges for maintaining its aesthetic appeal and structural integrity.

Understanding the root causes of this yellowing and the methods to prevent and restore it is crucial.

Regular inspections, preventive measures, and timely interventions can ensure the longevity and pristine appearance of carbon fiber components.

Whether you’re a car enthusiast, a professional in the automotive industry, or someone who relies on carbon fiber for other applications, being proactive in its care can significantly enhance the lifespan and performance of your carbon fiber items.

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Sean Mendez

Hi, I am Sean, a self-confessed petrolhead. I live in Boise, Idaho with a busy family of four and our energetic Labrador retriever. Thank you for visiting my website. You can find my email on the contact page.

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