DIY headlight polishing: How to restore your lights at home

Over the decades, the automotive industry has seen significant advancements in headlight design. The shift from glass lenses to plastic covers was not only aimed at reducing the weight and cost of parts but also at improving the durability of headlights during manufacturing and transportation.

However, this transition has introduced new issues. Over time, environmental factors such as UV exposure and contamination can cause plastic headlights to yellow and become cloudy, which poses serious aesthetic and functional problems.

Why address yellowed headlights?

Yellowing headlights are more than just a cosmetic issue. Discoloration and cloudiness reduce the light transmission of headlights, severely impacting nighttime visibility. This reduction in light output can decrease driving safety, especially in dark, rainy, or foggy conditions. Additionally, poorly performing headlights can cause problems during technical inspections, potentially causing the vehicle to fail if the lighting is deemed inadequate.

Regular inspection and maintenance of headlights are crucial for both safe driving and maintaining the vehicle's appearance.

Headlight replacement, polishing, or coating: What's Best?

When dealing with yellowed headlights, you have three options: replacement, applying UV protective coating, or polishing. Replacing headlights can be costly, often running into several tens of thousands of forints or more, depending on the vehicle make and model.

On the other hand, headlight polishing offers a more cost-effective alternative. Polishing kits and techniques allow you to restore the surface without replacing the entire headlight. The cost of polishing typically ranges around 10,000 to 15,000 forints, making it a significant savings for car owners. Polishing is also often simpler, quicker, and can be done at home.

The most effective solution is to use a headlight restoration coating. This provides a durable, flexible finish that resists damage and includes a strong UV protective layer, extending the lifespan of the headlights by several years. It's easy to use at home and restores the like-new appearance of any polycarbonate headlight.

Steps for Headlight Polishing

1. Cleaning:
Begin by thoroughly cleaning the headlight. Use warm water and car soap to remove surface dirt and dust. This step helps prevent additional scratches during polishing. Avoid using harsh chemicals that could damage the plastic surface.

2. Masking:
Next, mask the area around the headlight using painter's tape and masking paper. This prevents damage to the surrounding paintwork or accidental scratches during sanding. Masking also helps keep debris and excess material from affecting unwanted areas.

3. Sanding:
Use wet sanding paper for this step. Start with a coarser grit and move to finer grits. Sand the surface evenly, keeping it continuously wet to avoid excessive heat buildup and surface damage. Coarse paper removes the most significant contaminants and surface oxidation, while finer papers provide a smooth finish. For heavily damaged plastic, consider using a sanding machine.

Sanding Paper Selection for Headlight Coating (Machine Sanding):
- Slightly damaged, yellowed headlights:
1. Wet sanding with P1000 grit
2. Wet sanding with P2000 grit

- Heavily damaged, yellowed headlights:
1. Dry sanding with P180 grit
2. Dry sanding with P320 grit
3. Dry sanding with P500 grit
4. Dry sanding with P800 grit
5. Dry sanding with P1000 grit
6. Dry sanding with P2000 grit

Sanding Paper Selection for Headlight Polishing (Hand Sanding):
- Slightly damaged, yellowed headlights:
1. Wet sanding with P1000 grit
2. Wet sanding with P1500 grit
3. Wet sanding with P2000 grit
4. Wet sanding with P2500 grit

- Heavily damaged, yellowed headlights (Machine Sanding):
1. Dry sanding with P180 grit
2. Dry sanding with P320 grit
3. Dry sanding with P500 grit
4. Dry sanding with P800 grit
5. Dry sanding with P1000 grit
6. Dry sanding with P2000 grit
7. Dry sanding with P2500 grit

4. Polishing:
After sanding, clean the surface with a silicone remover. Apply a suitable amount of polishing compound to the polishing pad and spread it evenly. The polishing compound will refine the surface and restore the headlight's original brightness. Occasionally wipe the surface with a soft cloth or microfiber towel to check the results. Continue polishing as needed until you achieve the desired finish.

5. Applying Headlight Coating:
If you opt for coating, clean the surface with a silicone remover after sanding. Activate the hardener by pressing the button at the bottom of the bottle (avoid hitting it as this can damage the bottle).

Coating Application:
1. Apply a thin, even layer to the headlight.
2. Allow it to ventilate for 10 minutes (at 20°C).
3. Apply a medium layer.
4. Let it dry at room temperature (20°C) for about 8 hours.

Important Tips and Safety Precautions

Always follow the manufacturer’s instructions and recommendations when polishing headlights. Each polishing kit and protective coating comes with a detailed user guide, including information on proper application and safety measures. Incorrect use or unsuitable products can damage the headlight surface and impair the results.