Headlight restoration kit, or have it done?

A headlight restoration kit can do a good job on a lens that is only hazed. On a lens that has gone properly yellow it needs sanding, a drill and a steady hand, and the part people skip at the end is the part that decides how long it stays clear.

This page sets out the two kinds of kit on sale here and what each does to the lens. If you decide to hand the job over, our headlight restoration page lists the steps and has the booking form.

Why the lens goes yellow

1 The lens is clear plastic, and from the factory it carries a hard coat that blocks the sun.
2 That coat wears with years of sun and washing. Once it is gone, the plastic itself starts to oxidise, which is the yellow, cloudy layer you can see in daylight.
3 Sanding takes the oxidised layer off, and with it whatever factory coat was left. The plastic underneath is clear and has no protection at all.

So a restoration is two jobs: take the damaged surface off, then put a protective coat back on. Kits and crews differ in how they handle each half. The other signs that a lens needs it are in 5 signs you need headlight restoration.

The two kinds of kit

Wipe-on kits: A cleaner and a coating, applied by hand. No sanding and no drill. Meguiar’s, for one, sells a two-step kit described as clean and coat, and the maker says it keeps headlights clear for a year. These suit a lens that is only lightly hazed. They do not take off yellowing that has gone into the plastic, because nothing in them cuts.
Sanding kits: Abrasive discs in steps from coarse to fine, a polish, and a protectant. The 3M kit runs its discs on a household drill at 1,200 to 1,600 rpm, with masking tape round the lens to protect the paint, and finishes with a wax. This is the kind that removes real yellowing, because it takes the damaged surface off.

Read the box for the last step. A wax protects for as long as a wax lasts, and washing takes it off. A kit that ends with a UV coating is doing the job the factory coat used to do.

The coat at the end decides how long it lasts

A sanded lens with nothing on it is bare plastic in full sun, with none of the protection the factory coat gave it. It looks right on the day, and the same sun that yellowed it the first time starts on it again straight away.

Whichever route you take, ask what goes on after the polish. Our crew sands and polishes the lens, then applies a UV-resistant sealant before the final check, the same steps listed on the headlight restoration page.

When to hand it over

The yellowing is heavy: Deep yellowing needs the coarse steps, and coarse sanding done unevenly leaves patches you see every time the lights are on. A curved lens is harder to sand evenly than it looks.
You have no drill, or no shade: Sanding kits assume a drill at a set speed. The coating at the end wants a cool, dry lens out of the sun, which is not easy in a driveway at midday.
You want the paint around it left alone: The tape is there because a slip with a disc marks the paint or the bumper.

And some faults are not for a kit or for us. A cracked housing needs replacing, a blown bulb needs changing, and water on the inside of the lens is a seal problem, because sanding only reaches the outside. Aiming the beam is an alignment, which wants a garage with the rig for it.

Have the crew do it at your address

If you would rather not sand your own headlights, the headlight restoration service page lists each step and has the booking form. Describe the lenses or send a photograph, and we can tell you whether it is a restoration job at all.

Book headlight restoration Or text the crew

Sources

3M Headlight Lens Restoration System 39008, directions for use: masking, abrasive discs on a 1,200 to 1,600 rpm drill, polish and wax. 3m.com
Meguiar’s Two Step Headlight Restoration Kit G2970, product description: no drill, no sanding, clear for one year. blade.ph
KBS Coatings on headlight clear coat damage: the factory UV coat on polycarbonate lenses and what happens once it wears. kbs-coatings.com