DIY – Polishing Oxidized Headlights

3

October 3, 2013 by quirkyuncle@gmail.com

Don’t let this happen to you! Headlight oxidation is preventable!

Polycarbonate headlights are prone to oxidation that limits their light output and makes the lenses look cloudy and old. Aside from ruining your car’s aesthetic, the reduced illumination caused by oxidized headlights presents a safety issue. Fortunately, polycarbonate headlight oxidation is something that can be easily and inexpensively avoided and corrected.

Headlight before polishing…

Before polish1

And after…

After polish1

Tools and Time

Tools: None
Supplies: Plastic polish with UV inhibitor, soft cloth
Time: 15 minutes
Difficulty: Easy

You can purchase a Meguiar’s PlastX Clear Plastic Cleaner and Polish from Amazon.com.

All about oxidation and headlights

Oxidation is a normal chemical process. For metals, oxidation is seen as rust, corrosion, and tarnish. There is no way to totally stop oxidation: as Neil Young said, “rust never sleeps.” Treatments and coatings can slow the process, but if a material is susceptible to oxidation, it will eventually oxidize.

Polycarbonate is a type of plastic that was selected for use in automotive headlights because it is strong and resists impact. Typically, most of the lights on a car are made from acrylic, which might be more resistant to oxidation than polycarbonate, but cracks and shatters more easily when something hits it. On the front of a car, you want your headlights made of something tough that holds together if it is struck by road debris.

Like metals, plastics are oxidized through a chemical interaction with their environment. Polycarbonate oxidation speeds up when the material is exposed to ultraviolet (UV) light. Left untreated, oxidized polycarbonate headlights eventually develop a yellowish haze that looks like frosted glass. To maintain headlight clarity for as long as possible, you need to protect your headlights from UV light, just like your protect your skin so you don’t get sunburn.

From what I can tell, during manufacture, polycarbonate headlights are coated with a silicon UV-resistant compound to delay their oxidation. Once this factory coating wears through, the headlight begins to oxidize. This is a key point: even though the UV-resistant coating is invisible, it needs to be protected. However, since the headlights are on the front of your car, a harsh environment where they are subjected to weather extremes and are under constant bombardment by abrasive particles while driving, the loss of protective coating is pretty much inevitable.

Preventing headlight oxidation

You protect your headlights in the same way you protect the paint on your car: by applying a good quality car wax or paint sealant (I’ll refer to both of them as ‘wax’ in this article) that contains UV protection. This ‘wax’ protection adds an additional protective layer to the headlight surface.

Make sure that you use a pure protectant wax on your headlights and not a ‘polish’ or ‘cleaning wax’. Polishes and cleaning waxes contain abrasives that will only remove the protective coating from your headlights more quickly – definitely not what you want to do. With new headlights, the goal is to have the factory coating remain intact as long as possible. Once oxidation starts, and only after it starts, you’ll need to move on to the next stage: Correcting minor oxidation.

So how long will the factory coating on my headlights last? Good question. So many variables are involved, it’s impossible to predict. I’ve noticed the oxidation beginning to form on the headlights of cars we’ve owned after an average of four or five years. Some headlights remain unoxidized longer, some for less time: there appears to be no rhyme or reason. All I can say for sure is that the headlights of your car will oxidize, eventually.

Correcting minor oxidation

Once you notice oxidation beginning on your car headlights, it can quickly be removed using a plastic polish specifically designed for the purpose that includes UV inhibitors.

Polish and rag

Remember, starting to use polish on your headlights is a one-way street: once you start polishing your headlights, you’ll need to continue polishing them on a regular basis to keep them looking clear. Fortunately, polishing a headlight an easy process that takes less than 15 minutes, if you do it before the oxidation gets out of control.

To polish a lightly oxidized headlight, complete the following steps:

  1. Wash the headlights with car-wash soap to remove any grit and debris on their surface. Allow to dry. If you run your finger across the surface of the headlight, you can feel the roughness caused by the oxidation.
    Before polish2
  2. (Optional) You can tape off the painted areas around the headlight with masking tape, if you tend to be messy. If you are careful, you don’t need to do this. A little plastic polish won’t hurt your paint, if you remove it carefully before it hardens. If you are a wild and crazy polisher, save yourself some cleanup time and tape off the area.
  3. Apply a small quantity of polish to the headlight surface.
    Apply polish
  4. Polish the headlight surface with a soft cloth, using a circular motion. You need to apply some pressure when polishing, but the abrasives in the polish should do most of the work. Apply additional polish, as needed. You do not need a lot of polish, just enough to work the surface – applying excessive polish is wasteful and makes makes it more difficult to remove.
    Polish

    After you have fully worked the polish, there will be a very thin coating remaining on the headlight surface. The oxidation that was removed during polishing can be seen on your cloth.

    Oxidation on rag

  5. Using a clean area of the cloth, polish the headlight surface to remove the haze of any remaining polish.
  6. If any oxidation remains, repeat steps 4 and 5 until the headlight is clear and oxidation free. The first time you polish the headlight, or if you’ve waited too long between polishings, you might have to make several passes. The headlight surface will feel very smooth after the oxidation is removed.
    After polish2

If I repeat this process on a set of headlights every month or two, they always look great. In fact, doing it often actually makes their clarity improve over time.

A note about headlight de-oxidizers…

While researching this article, I came across several products that called themselves chemical headlight de-oxidizers. Each claims to remove headlight oxidation without polish or abrasives. While this seems like a great idea, the whole concept seems rather dubious: if I’m able to feel the roughness of oxidation on a headlight, and then feel its smoothness increase as the headlight visibly becomes more clear due to polishing, I’m not sure how wiping a few drops of a chemical across the oxidized surface will fix the problem. The websites linked to these products present information in quite a sensationalistic manner, leading me to question them even more. The videos that show how to use the products and their results appear less than stellar on lenses that are not like the clear-as-glass headlights seen in this posting.

I could be wrong. If you have any experience that indicates the validity of these products, or if you are a seller of these products willing to send me a sample for testing, please contact me. I’m always eager to learn something new and will happily revise this posting, as appropriate.

What to do if oxidation has gone too far

Oxidation extreme

If you wait too long, your headlight will look like frosted glass. A headlight in this condition is too far gone to be corrected by the polishing method given above. Reconditioning a headlight that is heavily oxidized can be accomplished at home using inexpensive, readily available products. A headlight that is heavily oxidized can be vastly improved, but will seldom look like new. These repairs are not permanent and need to be repeated every couple years. Still, it is a lot better than buying new factory headlights, which can cost over $1000 each.

Look for another posting in the near future that discusses repairing heavily oxidized headlights.


3 comments »

  1. Leslie says:

    Your estimate cost of over $1000 each is grossly over exagerated. I could buy new replacement headlights (including the lens) for $100 each. The dealer wanted $189 each.

    • quirkyuncle@gmail.com says:

      Price of new headlights depends on the type of car and its age – and whether you can afford to spend $200.

      Older cars tend to be cheaper, since they are trying to clear stock. Domestic are generally cheaper than foreign. Aftermarket lights are also cheaper than OEM. Prices tend to rise a lot when you get into more exotic headlight designs (xeon projectors, etc.).

      Your point is well taken: yes, there can be deals to be had.

  2. Bobby Johnson says:

    Two points
    1. I agree the cost of headlights easily exceed $1000 based on type of car and operation of the headlight.
    Bulbs are a thing of the past, electrified gas used in some vehicles require a serious injury warning label near the headlight. Infiniti uses this type of system, it is very expensive to replace.
    2. As with some other articles I have read there is a misconception of what oxidation is.
    Your understanding of oxidation is flawed.
    acrylic or plastic oxidation is not like metal oxidation it does not result in a break down of plastic it is the opposite. It is build up of material that collects on the surface and bonds to the plastic. It is not damage it is a coating.
    Removal of this coating exposes the physical condition of the lens.
    The de-oxidizer does this.

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