Headlight Restoration

Polycarbonate lenses before & after

Modern automotive lenses are made of high impact thermoplastic based acrylic / polycarbonate, this allows for headlight designs in a variety of shapes and sizes, making their configuration, one of the most diverse in automotive design history.

This material is versatile and beautiful, but it has a limited life expectancy. Unlike Glass which would last virtually forever, climate and environmental contamination has a negative impact on their appearance.

Cause

Over the years, the polycarbonate headlight lens on any vehicle are subjected to heat and humidity - high Intensity discharge (HID) bulbs also bulbs also contribute to the deterioration of the polycarbonate lens as they emit heat from inside the lens, heat from the engine bay, radiation heat and humidity from the atmosphere, depending on climate and season

Other environmental contaminates can have a negative impact, they rapidly succumb to photo degeneration and oxidation caused by ultra violet (UV) radiation and the lens becomes hazy and yellow and when exposed to environmental contaminants like salt air, acid rain and excessively harsh (alkaline) cleaning chemicals.  Road salt is also a yellowing agent, and then there is the effect of high-speed collision abrasion from dust, road grit and insects.

Effect

All of the above will cause the lens to become oxidized (opaque) causing lack of available road illumination. Hazy headlights aren't just a cosmetic issue; they’re a safety issue, too and replacing headlights can get extremely expensive, and is often unnecessary.

Remedy

Because the damage on the lenses is usually purely superficial, they can be restored to an as-new clarity with minimum time and effort with the headlights still on the vehicle. If the lights are pitted, they will have to be sanded. But if they are just dull, hazy and yellow, surface polishing with a chemical paint cleaner (Werkstat Prime Strong). This formula takes a step toward a finishing polish and can eliminate the need for a more aggressive polishing in many instances.

This product contain  mild abrasive so will help to remove oxidation, light swirl marks and scratches, used with the right pad (LC White light polishing foam pad,  orbital speed #3 - 4)

What condition are your headlights in?

1.      Do your lenses appear to have a thin layer of plastic wearing off the lens?

2.      Is the lens deeply pitted?

3.      Are there scratches visible on the surface of the lens?

4.      Does the lens appear to have thousands of tiny micro fractures in it?

The above conditions go beyond the effect of natural oxidation. Dependent upon the extent of the damage it can sometimes be restored by resurfacing utilizing wet-sanding and/or polishing systems.

Headlight Kits

Be cognizant that some ‘headlight restoration kits’ use fillers (Kaolin or Dimescous Earth) to ‘mask’ as opposed to an abrasive that will remove lens surface problems.

3M Headlight Restoration Kit (136050) - a complete headlight restoration; from scratch removal to sealant; the kit contains a sealant that requires ultra violet curing (UV lamp or in sunlight, 10-15 minutes) aerosol spray hard coat to protect the restoration. Ford Motor Company has tested and approved their sealant in their Weatherometer in Detroit exhibiting a durability of 3 years minimum.  This is currently the only OEM tested and approval product of this type that meets standard ASE J2527 paint testing protocols.

Lexan® Polycarbonate

In the late 1980’s, vehicle manufacturers changed the lighting lens system materials used for head lights from glass to a polycarbonate. Original equipment manufacturers (OEM) needed a material that could be moulded to aerodynamic shapes and was lightweight. A polymer material, Lexan® Polycarbonate, which was both lightweight and could be moulded into many different shapes aerodynamic shapes, making it suitable for sports cars.

Is a registered trademark of SABIC Innovative Plastics; a highly durable polycarbonate resin thermoplastic intended to replace traditional glass and Plexiglas where the need for strength and impact resistance justifies its higher cost.

Vehicle Head Lights

To the naked eye one cannot tell that these plastic lenses are actually a porous material that expands ever so slightly when it gets hot. Degradation of the lens occurs over time Having your headlights on or being exposed to the heat of the day causes expansion of the micro-the pores, allowing debris from the road to get in.

Headlights are usually made from Polycarbonate; it has its advantages (light weight, easily formed to differing aerodynamic shapes, etc) but also has its disadvantages; namely oxidation / discolouration or more correctly photo degradation

Tail light, turning and signal (turn indicators) are usually made from heat and impact resistant acrylonitrile butadiene styrene (ABS)

Oxidation (photo degradation) - of the polycarbonate headlight causes it to dry out the plasticizers and become cloudy or take on a yellowish tinge. Ultraviolet (UV) rays from the sun also cause the lens to develop micro-cracks, hastening the colour change. If the lights are pitted, they will have to be sanded. But if they are just dull, hazy and yellow, surface polishing will restore clarity. This debris can be removed with a chemical paint cleaner (Klasse AIO or Werkstat Prime Strong)

Surface damage - when the lens starts to exhibit an opaque appearance and then a yellow hue on the outside of the lenses, this is due to ultra violet radiation (UV), which also causes micro-cracks. Road grit / debris and harsh chemicals cause surface scratches. This can severely restrict the amount of light reaching the road and this becomes a safety issue as you rely on the vehicles lighting system to see what’s on the road ahead and adjust your driving accordingly.

1.      Wash and thoroughly dry the lenses

2.      Tape-off all around the lenses so that you don't accidentally wet sand or buff the surrounding areas.

3.      Use a Nanoskin surface prep towel to remove any surface contaminants

4.      Using a random orbital buffer with a 3.5-inch backing plate and a 4-inch (Lake Country (LC) Mfg) White polishing pad or a terry cloth applicator

5.      Place a small dab (about ½-inch diameter) of plastic polish on the foam pad or applicator.

6.      Place the pad on the lens surface and turn on the machine (speed #4)

7.      Polish the lens repeatedly in a left-to-right and an up and down pattern.

8.      Continue polishing until all the polish is gone

9.      Wipe the lens with a damp Microfiber towel

10.  Inspect the lens; repeat the polishing process 2-3 times as necessary

11.  Finally wipe down the headlight surfaces with isopropyl alcohol (IPA) or a tack rag to eliminate any residue.

Notes –

1.      Polishing or wet-sanding  will not remove clarity defects that are within the plastic but it will remove external/surface scratching and ultra violet (UV) oxidation (yellowing) as well as OEM applied UV protection that should be replaced

2.      Softer polycarbonate resists breakage but will oxidize faster.

3.       Don’t use abrasive or highly alkaline cleaners.

4.      Never scrape the sheet with squeegees, razor blades or other sharp instruments.

5.      Don’t clean Lexan® Polycarbonate products in the hot sun or at elevated temperatures as this can lead to staining?

Original equipment material (OEM) suppliers started to add ultra violet resistant (UV) coating to the surface of the lens in an attempt to reduce this condition and prolong the usable life of the lens. This protective coating is very thin (25 µ (microns or 1 Mil)

Removing oxidation or scratches from vehicle headlights or brake lights (also polycarbonate) also removes the OEM ultra violet protection, which prematurely decreases the durability of the lens. Surfaces that have yellowed are a sign that the ultra violet (UV) sacrificial coating has failed and must be resurfaced and recoated.

Ultra Violet Protection - polishing or wet-sanding headlights without renewing their ultra violet (UV) protection is a false economy, unless this protection is replaced, the end result is that you'll have to do them again in a few months (repeat this polishing process enough and there will be no material left to work with)

Preventive Measures

There’s nothing you can do to stop plastic from degrading, but you can certainly slow the process down, however, by avoiding salted roads and prolonged sun exposure whenever feasible.

Cleaning the lenses on a regular basis (whenever you wash the vehicle) and using a mild , polycarbonate compatible polish on a semi-regular basis, and some companies even offer clear protective films that provide a buffer between your lenses and the elements. Such measures do more than just promote safety; they‘ll also improve the resale value.

Optimum Opti-Lens™

In order to restore the lens back to its OEM standards a new ultra violet (UV) resistant coating must be re-applied. For brand new vehicles, Optimum Opti-Lens™ is formulated with an acrylic and various co-polymer resins designed to cross-link with polycarbonate and will adhere to the factory-applied film to increase its life span. Or on refinished headlights, where the coating has failed and has been removed do to polishing.

Optimum Opti-Lens Headlight Coating - an advanced, resin-based coating Opti-Lens is a hybrid coating based on Opti Coat. OPT added acrylic for flexibility due to the constant expanding and contracting and increased the ultra violet (UV) absorber content to accommodate the absence of protection inherit to polycarbonate. This product is specifically designed to provide protection for OEM headlights, taillights and other poly-carbonate surfaces

Apply directly to the headlight using a poly foam applicator or Optimum Dual Pro Applicator. Work a small amount of product over the lens using overlapping passes until it appears to melt into the lens and disappear. Remove any streaks or high spots with a soft microfiber towel. It takes approximately 30 minutes to cure before it can be exposed to water. Allow 24 hours to pass before washing or cleaning with pressure.

This product can only be removed via mechanical means (abrasive polishing) it does not wear off.

·         Apply a thin coat side to side, which will leave a trail behind the applicator and then top to bottom seeing a trail behind the applicator.

·         When 80% of the area has flashed to clear (rainbow colours disappeared), lightly buff off any remaining product with a micro fibre.

·         Don’t buff unnecessarily during application or when removing excess. It’s easy enough to remove a dried high spot by hand and it’s better to remove them after it cures

.Alternate Product

G|Techniq C4 is a permanent headlight sealant; it has a durability of ~ two years (dependent upon conditions encountered).

Headlight (Physical) Protection

Even after a headlight restoration project prevention is always better than a cure; with the average cost of replacement head lamps and fog lamps spiraling to nearly $300, it is nice to know that there is a product available to protect your car against the perils of the open road. These products are made from a proprietary, scratch-resistant, urethane material coupled with the strongest optically clear adhesive available

a)      Protect your expensive headlamps, before it's too late. WeatherTech® LampGard™ uses a tough 40 mil thick, double-polished urethane material that is optically clear and applies (peel & stick) directly to the surface. This product has built-in ultraviolet inhibitors that help prevent the material from drying, hardening or discolouring. Custom die-cut to fit your specific vehicle for a precise, perfect fit, it comes with easy-to-follow instructions and applies to headlamps, fog lamps, turn indicators and parking lights (when applicable) to protect them from scratching, cracking and pitting.

b)      XPEL™ Designed for maximum durability, these light covers were originally tested under the harshest of circumstances with amazing results. Both in the real world and in the lab, these covers have proven that they will withstand a barrage of 1" diameter stones (about 1oz.) at speeds up to 120 M.P.H. with no damage to the lens they protect. It is nice to know that your expensive lenses are protected in every scenario. We are so confident in our product that we offer a 5-year warranty to leave you with complete peace of mind. Headlight protection film can also improve the look of old headlights by reducing the haze build-up

Relevant Articles

1.      “Environmental Damage” - http://www.autopia.org/forum/car-detailing/136393-environmental-damage.html#

2.      “Nanotechnology coatings “- http://www.autopia.org/forum/autopia-detailing-wiki/136613-nanotechnology-coating-products.html

3.       “Oxidation or Clear Coat Failure?” - http://www.autopia.org/forum/autopia-detailing-wiki/141208-oxidation-clear-coat-failure.html