Glass will always behave in a relatively predictable way. There are a few “enemies” of windshield repair. Extreme temperatures is one of them. Glass tends to expand in the heat and contract in the cold. The windshield is comprised of three layers, UV glass on the outside, UV glass in the interior of the car and a synthetic in the middle, laminated together to create a strong bond. When it is very hot outside, especially when the car has been sitting in direct sun, the windshield can heat up to well over 110 degrees F. More than likely, drivers will run their car air conditioner on a hot day and if there is a rock chip or a small crack on the windshield, the variance in the temperatures from the outside of the windshield and inside the car, can easily cause the damage to grow in size resulting in the need for a costly windshield replacement. Here’s why: The outer layer of glass is expanding in the heat. The middle layer is fixed, and the inside layer is contracting from the cold air blowing from the air conditioner. This causes a certain amount of pressure, and to relieve the tension, the glass cracks. It is the same principle that cause a hot glass to shatter if it is held under cold water or visa versa. In the Winter, the same thing can happen, only in reverse. The outer layer of the windshield is icy cold and when the car heater is turned up, the inside layer begins expanding with the heat.
The take away from this, aside from having your windshield repaired asap when you have a rock chip, is:
- Avoid extremes in temperature. If you are still using the vehicle before you have a chance to have it repaired, try to park it in a shaded area, out of direct sunlight.
- Avoid using sun reflectors that are shiny. Shiny reflectors will shield the interior of the car by reflecting sunlight away, but they are also known to heat the windshield to temperatures that can easily cause a small rock chip to spread. Instead, use opaque, or satin-finished sun guards.
- If you are using your air conditioner, keep it on low, and keep the setting adjusted so that the air flow is focused mainly on your legs and not on the windshield.
-Simple tips that can help to save your windshield.