Polishing plastic headlights – this is how it works step by step

 

Plastic headlights become dull over time and can yellow. In this article, you will learn how to polish the headlights on your car yourself step by step, what materials you need and what the legislator says about refurbished headlights.

The plastic covers of the headlights of modern cars have to withstand a lot over time. It is unavoidable that they will yellow, scratch and become dull over time. As a result, the luminosity decreases. Matte and yellowed plastic headlights can only illuminate the road poorly. Visibility in the dark becomes significantly lower. If the covers are scratched, oncoming traffic can be dazzled by annoying light reflections under certain circumstances. If you have a little manual dexterity, you can recondition the plastic cover of the headlights on your car. We will show you how you can polish plastic headlights yourself and what materials you need for this in the following step-by-step instructions.

Polishing plastic headlights – step by step to the perfect result

In stores, you can get sets from various suppliers that contain everything you need to polish plastic headlights. However, you can also put together these materials yourself. To polish the plastic headlights on your car, you will need:

Adhesive tape / painter's tape

Microfibre cloths

lint-free, soft wipes

Wet sandpaper 800, 1500 and 3000 grit

Plastic polish

Plastic primer in the spray can, transparent

Clear coat in a spray can

Step 1: Wash the headlights thoroughly

An important step before polishing plastic headlights is thorough cleaning. Use lukewarm water and a car shampoo for this purpose. Remove all dust and dirt from the headlight covers. Then dry the headlights with a microfibre cloth or another cloth that is as lint-free as possible.

Step 2: Assess the damage

Before you reach for sandpaper, you should take a closer look at the damage to the headlights after washing. You can fix slight yellowing, milky cloudiness and superficial scratches. Deep scratches, for example from shopping trolleys or the craters of stone chips, can no longer be repaired. In this case, the only thing that will help is to replace the headlight.

Step 3: Mask the body around the headlight

To avoid damaging the paint on the fenders or bonnet when sanding, you should mask the edges around the headlights with adhesive tape or painter's tape.

Step 4: Sand down the headlight cover

Use only wet sandpaper to sand the headlight covers. Always keep the paper well moist so that sanded plastic cannot get stuck and cause deep scratches. Sand the surface as evenly as possible with little pressure. Start with a wet sandpaper with an 800 grit.

In between, you should rinse the headlight with water again and again. The result should be a uniformly milky-cloudy-matt plastic headlight. Repeat this process with a slightly finer 1,500 wet sandpaper. Finally, wet sand the entire headlight with a very fine 3,000 or 4000 grit sandpaper. After the last pass with the very fine sandpaper, the surface of the headlight is almost completely smooth and shiny again. But only almost.

Step 5: Polish plastic headlights to a high gloss

After sanding comes polishing. You can polish plastic headlights to a high gloss by hand or with a polishing machine and a suitable polishing paste. You can also use a polishing attachment for a drill or a cordless screwdriver. It is important that you polish slowly and with little pressure. If the polishing machine runs too fast and they apply too much pressure, the customer will get too warm and the surface will smear.

Step 6: Apply plastic primer

After polishing, you need to wash off all polish residues thoroughly. Then spray on a transparent plastic primer. The primer is important so that the subsequent clear coat coating adheres.

Step 7: Apply clear coat

Finally, they have to apply a layer of clear varnish. Try to apply the clear coat as evenly as possible so that the clear coat layer is the same thickness everywhere.

Are there any home remedies for polishing plastic headlights?

There is only one home remedy for polishing plastic headlights that is reasonably suitable. This home remedy is ordinary toothpaste. Toothpaste contains very fine abrasives, usually marble or another light-colored rock powder, which are used to remove plaque from the teeth. Many other polishing agents for technical applications also contain marble powder. To polish, apply some toothpaste to a damp, soft cloth.

Rub the cloth in circular motions over the surface of the headlight. With a bit of luck, you will achieve an acceptable result. However, it is better to invest some money in a special plastic polish. Under no circumstances should you use a conventional paint or metal polish to polish the plastic headlights. Paint and metal polishes may destroy the surface more than they provide smoothness.

Can you polish plastic headlights?

No, as a matter of principle, you are not allowed to polish plastic headlights or headlights with lenses. The reason for this is the so-called type approval of the headlights. Each headlight must have an EU type approval in order to be installed as standard in a car. Changes to the headlights are therefore not permitted. With polishing, you change the headlight, even if only minimally.

This means that the type approval expires. And with the type approval for the headlight, the operating approval for the entire vehicle also expires. Theoretically, you will then no longer be allowed to drive your car. If an attentive inspector sees at the next general inspection that the headlights on your car have been processed, you will not receive a sticker.

However, the ADAC has been able to determine in tests that a professionally polished headlight can definitely keep up with a brand-new one and has significantly better light properties than a yellowed headlight. The ADAC has therefore been calling for the reconditioning of plastic headlights to be legalised for several years. Especially in view of the high cost of new headlights. Plastic headlight covers cannot be replaced separately. A complete new or good used headlight must always be bought and installed.

How can you prevent plastic headlights from becoming dull and yellowing?

The plastic covers of headlights are made of very resistant polycarbonate (PC). In addition, a clear coat is applied to protect the plastic from UV rays. However, this clear coat does not last forever. Over time, the clear coat will come off and the plastic cover will start to yellow. This cannot be prevented, but it can be delayed.

Always use not only plenty of water to wash plastic headlights, but also a mild shampoo. Dirty headlights should not be washed with a dry cloth. Always keep a large distance from construction site vehicles to avoid damage caused by stones thrown up from the tires of the vehicles. You should avoid unpaved roads and gravel paths as much as possible and also keep a large distance from vehicles in front.