The need for headlight lense polishing arises every few years on the models with plastic polycarbonate lenses. Slowly the lenses get pitted from dust and sand, and damaged from ultraviolet radiation from sunlight. The damage happens slowly in most circumstances, although driving in one Nevada sand storm can badly mar the surfaces of the lenses. Damaged headlight lenses can reduce illumination by way more than half, and thereby pose a serious safety issue. Sometimes we see lenses that are virtually opaque, and night vision is obviously compromised. When driving in a well lit town, a driver may not be aware that they are a rolling hazard, but out on some dark and lonesome country road, the situation can be perilous.
The first part of the job involves prep work. The painted areas around the headlight lense must be protected. Ordinary masking tape is inadequate, and expensive gaffer tape must be employed. Cheap tape can roll up or tear when the sanding pad makes contact, and instantly leave a life long scar. The surface should be cleaned before applying the tape, so proper adhesion is ensured. Some finesse is required to roll the tape around the inner edges, and poke it securely into the corners. A cheap paint job that is already pitted may not survive the grip of the wrong tape. Chunks may pull off when the tape is removed. The engine bay and surrounding spaces should be covered with drop clothes, as the sanding compounds are going to spray some debris.
At Karmakanix, we use the 3M headlight lense polishing kits that require a total of 4 steps, as the grit slowly increases until the surface gets completely smooth again. Badly pitted headlights can take significantly longer to get right. The sanding discs need to be angled properly to avoid digging into the headlight lense. Curved lenses are a challenge requiring a bit of an artistic touch to get the finish even. It only takes a moment of inattention to badly gouge the plastic when using the coarser compounds. Some cars have headlights that fit so tightly, that getting the edges polished really brings out the artist’s touch. We do not use a UV coating, as we have found that the cheaper coatings may look yellow, pit or peel very easily, and present a time consuming mess when the job is done again later.
The final step is to clean the sanding debris and remove the protective tape. Proper protection will avoid a big cleaning effort. A final wash and dry will finish of the process. Our goal is to return the car with the headlights in show room condition. No gouges or swirls, and completely transparent. And no damage to the paint or chrome. Welcome to successful headlight lense polishing.