Imagine driving in your car without it. Your windshield
that is. The wind at your face, blowing through your hair while you fly down
the road at high speeds. Sounds pretty neat huh. Fortunately the piece of
Glass in front of you while you drive is one of the most important safety
features of all cars today. Without it, stones, debris, weather, chickens
and other road hazards would do some serious damage to you and other
What is a windshield you may ask. Well it is 2 pieces of float glass with a plastic laminate sheet sandwiched between the glass. The reason for this is safety. Windshields which hold an asa-1 rating can and must withstand impact ratings. That means that if a stone the size of a pebble hits your window, it will not penetrate the glass, even if you are going at high speeds. The main reason for windshield breakage is due to the stone getting between the treads of tires and are flung in the air bouncing off the road and into the glass. The glass depending on the angle of the hit and how fast you are going can get damaged. These stone bruises are pretty ugly, and many people fear that because the glass is broken, the windshield will cave in on then. This is not exactly true except for another safety factor discussed later on. Remember a Windshield is 2 pieces of glass. The Plastic Lamination between them has protected the inner piece of glass. So all you are left with is an unsightly crack in the outside glass. Now you can live with the bruise or get it repaired or replaced.
The glass in the rest of the car is different. Around the 1950's the door glass and the backglass change to a tempered plate. It is just one piece of glass that is sent into an atmospheric oven that heats and quenches the glass which hardens it. PSI (pounds per square inch) can be in the 100's. Have you ever seen a door glass break. I'm sure if you take a hammer to it you would be surprise. You either must hit it many times or break it on the first shot. But when it does break it falls apart into hundreds of small glass beads. A good tempered door glass will not cut you. A poorly tempered glass will break in shards and can cut badly. One of the reasons for choosing and OEM glass product.
The reason for different types of glass in vehicles today is safety. We could not have tempered glass for Windshields on the roads in the United States. Although harder to break than a Windshield, tempered glass is can be very unstable. If the skin is broken, it could explode in your face while driving. The real reason for this product is incase of rollover. It is very difficult to cut through laminated glass. So if you are ever trapped in your car, its easier to get through tempered than laminate.
Many people are amazed that one cold winter day or hot summer day, they came out to the car and all of a sudden they noticed a long crack running through the windshield, or the back glass is broken in a million pieces on your back seat. It is not a happy experience. They wonder how this happened, and they are now concerned for their safety. Many people ask their Glass expert how it happened when they go to get it replaced. The answer is simple. The windshield at some point had a small crack or bruise. The tempered backglass might of had a defect. Glass is very susceptible to quick changes in temperature. For example, on one cold winter morning you get into your car to warm it up. When you turned on your vehicle, you hit the defrost button on to take the ice, snow or frost off the windshield. Due to the fast expansion of the glass, the defect in the window started to run into a crack. The other situation is the heat of the summer. You drove to the supermarket with the A/C on. You get out of the car and shop for an hour. The range of temperature went from say 70 degrees to almost 200 degrees. Yes, you literally can fry an egg on the dashboard in this situation. The quick change of temperatures with cars that have a stone bruise, or an improperly installed or defective windshield or tempered part can fail, an break.
At this point either with a stone bruise or cracked windshield your safety is being compromised. Even though the windshield will not cave in on you, it is not exactly safe and can pose as a dangerous situation. As vehicle manufactures started to streamline cars using Uni-Body design's, which now the car has no main frame, windshields now perform a very important safety factor for the structural integrity of the car. All cars now must pass certain roll over tests, and as the car manufacture lighted the weight of the vehicle, they made the windshield an important factor in roll over safety. With a cracked, or stone bruised windshield you are now compromising the structure of that rollover safety. Let me give you an example that a science teacher might have taught us in grammar school. Take an egg. Place 2 fingers on the top and the bottom of the egg. Now squeeze with all your might. What happened. Nothing right. Yes, mother nature created the perfect non breakable structure, so that when mother hen sat on it the wrong way, it would not break. However now take a needle and poke it through the egg. Just like the stone in the windshield. You have now compromised its integrity. Now take your fingers to the egg, and squeeze again. Opss...you now have egg all over your hands. The same theory is now being used in windshield glass, and god forbid you get into an accident and roll. Your windshield better be free of bruises or cracks.
Another very important safety feature is the glue in which your windshield rests on. That adhesive must be strong enough to keep you in the car if you get into an accident and are not wearing your seat belt. Many automotive urethanes now have a PSI(pounds per square inch)of 500 or more. In the old days Butyl was used to hold windows in. Butyl at its best was only 50psi. So when you have your windshield replaced by the Auto Glass Expert make sure he uses Automotive Urethane. In today's times there is NO SUBSTITUTE!!!
The biggest concern people have about replacing their windshield is breaking the original seal at the factory. However it is true that the glass installer must cut the old windshield out of the car, if properly installed the new seal is just as good as the one done at the factory. Again he must use OEM approved Urethane, and primers and must have the pinch weld free of dirt and solvents.
Another major concern that hits the hearts of all Glass Dealers and Customers is cure times. That is how long does it take for the Urethane (glue) to dry and become safe for the customer to drive. Don't be afraid to ask the Glass Dealer about this. Urethane Cure times can range from 2 hours to 48 depending on product, temperature, and humidity. At what point do they pass rollover tests. Most of this information can be obtained by the customer from the Glass Dealer.
The Internet Glass Network is comprised of Glass Dealers that have high standards and safety in mind. If you have a Glass or Auto Glass need please click on our order form to get information from a national vendor nearest you. Or visit our website at
or write to us at
or click the banner at the top of the page.