Two hundred years ago, cars didn’t have windshields or windows at all. Crazy, right? In contrast, today’s cars, trucks, and SUVs have multiple different types of glass.
What kind of glass is used for the windows in your car? Why does it matter? Keep reading to find the answers to these important questions!
Car Window Glass 101
When cars were originally invented, there were no windows. That’s because there didn’t need to be: cars just didn’t go that fast! (The very first cars went about 5 miles per hour! Look at very old photos of car drivers, and you might notice them wearing goggles to protect their eyes from wind, dust, insects, and cold.)
Eventually, car manufacturers added windshields and windows to the design. However, original car windows were made with the same type of glass used for your home windows. Can you spot why that would be a problem?
You guessed it: in the event of a crash, sharp and jagged pieces of broken glass would go flying toward the car driver and passengers. The glass used would cause serious injuries when broken.
Fortunately, today’s car window glass is far safer and studier! There are actually several different types of glass used for car windows.
Below, we break it down (or rather, in the case of car window glass, not break it down).
Laminated Glass
Laminated glass is a type of safety glass. It’s actually not a single pane of glass at all, but at least two panes of glass separated by a layer of polymer. The layers are sealed together and any air pockets removed using rollers or vacuum systems. Then, the layers of glass and polymer are heated to fully bond them together.
When hit, laminated glass tends to get a spiderweb-like cracking pattern—instead of shattering.
This type of glass is used for your car’s windshield (and sometimes the sunroof).
Because your car’s windshield is made of laminated glass, it’s able to withstand the small rocks and debris regularly flung at your car. It takes a lot to break laminated glass: unless you’re in a major car accident, your windshield will generally only see a few chips or cracks in the outer layer of the glass, at most.
As a bonus, laminated glass is very repairable: catch the chip or crack early, and you can fix the damage!
Tempered Glass
Tempered glass is another type of safety glass; however, unlike laminated glass, it’s not made of multiple layers.
Instead, tempered glass is a kind of strengthened regular glass. The “tempering” process increases the strength of the glass four-fold! Tempered glass can be made by rapidly heating the glass to more than 1,000 degrees Fahrenheit and then rapidly cooling the outside. It can also be made chemically, by immersing the glass in a bath of potassium nitrate.
As a result, when shattered, tempered glass breaks into small, pebbled chunks—as opposed to long, jagged shards. Broken tempered glass is much less likely to cause injury that way.
Tempered glass is used for your car’s rear windshield, side windows, and (usually) the sunroof.
You might be wondering why—since laminated glass doesn’t shatter—would the rest of the car’s windows be made of tempered glass? Wouldn’t it be safer? Wouldn’t you prefer that a stray baseball couldn’t shatter your rear windshield?
In fact, it’s important for some of your car window glass to shatter!
In some emergencies, it’s critical to be able to get in or out of the car as fast as possible.
Consider what might happen if your car went into a river or rising floodwaters: you might not be able to open the car doors or roll down the windows, but you would be able to break the tempered glass. (If every car window were made of laminated glass, you’d be stuck inside!)
Mirror Glass
As the name suggests, mirror glass is a type of smooth glass that has been coated (usually with reflective powder, aluminum, or silver) to be reflective.
Mirror glass is used in your rearview mirror and your side mirrors.
Your rearview mirror and driver’s side mirror are flat, while the passenger side mirror is convex. Why is that?
Reflections are impacted by how the mirror is shaped and how the light bounces off the mirror. (Think about how you look in fun-house mirrors!) The flat driver’s side mirror offers an accurate reflection of what’s behind your car on that side of your car; however, the downside is a narrower field of view. The convex passenger’s side mirror, on the other hand, reduces your blind spots on that side of the car (since the field of view is wider). The downside to the convex mirror is that it distorts the reflection. That’s why you see the warning, “Objects in mirror are closer than they appear.” It’s because the distortion from the convex shape makes the objects appear farther away than they actually are.
Together, the flat and convex mirrors allow you to safely see what’s going on around your car.
Need Help with Your Car Window Glass?
We’re here to help! Whether you need to learn more about your car windows (check out our blog) or you need glass repair or replacement, we’ve got you covered.
Call us today to get a free quote and on-site service from one of our expert auto glass technicians.
