Carl Benz’ conception of the gas-powered automobile in 1896 included the basics – a set of wheels, a working engine, a seat for passengers, and a fuel tank, all housed in a mix of wood and metal. It didn’t have a windshield yet, not until 1904. It was made with two panes of glass that provided a clear view until bumps in the road sent cracks across its surface.
The fragility of simple sheets of glass as a protection against inclement weather prompted several inventors to provide the solution. And from a solution it came indeed. Scientist and chemist Edouard Benedictus’ lab mishap led to the discovery of a substance that would be the precursor to glass laminants.
For over a century since the lab accident, the development of more durable windshields provided car drivers safety from moisture, debris, and all sorts of insects that might end up in their mouths or faces. Most automobile companies are employing better engineering to make sure windshields stay in one piece even after breaking.
The organization responsible for regulating headlight safety first came together as a result of windshield concerns. Since then NHTSA (National Highway and Traffic Safety Association) has set standards on the protective capabilities of windshields. This also includes visibility and resistance to frosting and fogging.
There are four test procedures and standard regulations concerning windshields. These are:
FY TP-103-13 (Windshield Defrosting and Defogging Systems)
FY TP-104-08 (Windshield Wiping and Washing Systems)
FY TP-301-04 (Windshield Mounting (*212/219/301F)
FY TP-301-04 (Windshield Zone Intrusion standard regulation)
These test procedures are available on the official NHTSA website.
What’s in a windshield?
Windshields are still made of glass. The only difference between the glass panes used in 1904 and the ones today is the technology used to increase its durability. Much like Gorilla glass used in phones, windshield glass is tempered for driver safety.
This is done by heating up glass to more than a thousand degrees and subsequently cooling it down. This rearranges the molecular structure of glass, and the structure is what makes it possible for it to break into several tiny pieces, a feature which makes it relatively safer compared to it breaking into big shards.
A windshield’s layering also plays an important role in the prevention of injuries. A layer of plastic is sandwiched between two sheets of glass. Since plastic is structurally more flexible than glass, it helps decrease the chances of the two individual panes from breaking.
The plastic layer also acts as a shock absorber of sorts, similar to how a rock’s impact would be softened when hitting a curtain. The plastic layer is also what makes it possible for manufacturers to slice or probe the windshield with minimal damage. The lamination process helps bond the surfaces of both the glasses to the plastic film.
Before buying windshield replacements, it’s important to know what type of damage can be repaired. There are federal regulations surrounding windshield replacement and repair so it’s important to know beforehand if a windshield can still be salvaged.
Cracks are the most common types of windshield damage. Cracks form from impact or from extreme temperatures. The general rule is to replace windshields if the crack extends into the edge.
If the crack on the windshield spans a dollar bill, it will have a higher chance of spreading. The cracking will also be exacerbated by extreme heat or cold. Any cracks less than three inches in length or chips with less than a diameter long can still be repaired.
Any type of windshield damage that is directly in front of the driver’s field of view should not be repaired. Repairs distort the glass surface and may affect the driver’s ability to see objects ahead. This means an automatic replacement no matter how small the damage is (or depending on state regulations on windshield replacement and repair).
Aside from size, the depth of the crack in a windshield also determines if it’s repairable or replaceable. If the damage on the windshield goes past the inner plastic lamination and through the other glass plane, a replacement is mandatory.
Other types of windshield damage include chips, stars, half-moons, targets (or bullseye), or any combination of these.
Repairs on the windshield involve boring a small hole into the windshield. The bore will not go through but just enough so they can inject a clear resin that will fill the cracks in.
Where to get a windshield replacement?
Auto Repair shops usually have a stock of windshields ready for mounting. They buy these directly from the manufacturers. They may also buy these from OEM or aftermarket suppliers.
The difference between OEM’s and brand manufacturer windshields is the distribution. Car assembly companies like Ford or Toyota buy from OEM’s to include windshields during the assembly phase. OEM’s make a variety of glass, including auto glass.
In the US, auto glass OEMs like Guardian Industries and Vitro provide windshields to major car brands. Aftermarket windshields also have the same specifications as OEM windshields except they’re available for retail, usually sold under a different company name. If it’s marked as made in China, it’s not counterfeit, as major OEM’s also come from the east.
Here’s a list of OEM auto glass manufacturers:
- AGC Glass Europe (has locations in France, Russia, Italy, England, Germany, and many more)
- Fuyao Group (China)
- Guardian Industries (based in the US but manufacturing is located in Spain)
- NordGlass (Europe)
- Pilkington, (trademark acquired by NSG Group from Japan)
- Pittsburgh Glass Works (US)
- Saint-Gobain Sekurit (France)