Damage to a windshield is both irritating and unsafe. The initial moment of a rock striking the glass is startling, and subsequently having to see the evidence of the impact every time you drive can be a source of frustration. While it can require a lot to crack a windshield because they are built to endure, there are several factors that can do the trick. Be aware of these to be safer on the road.
Examining Different Types of Window Damage
Let us first start by explaining what we mean by “crack a windshield.” Windshield cracks are streaks in which the structural integrity of the glass has been compromised. There are many different varieties, usually classified by where the crack occurs. Windshield cracks usually cannot be repaired.
The other major type of windshield damage is the chip. Chips are smaller, describing just the spot of impact where the glass was damaged. Chips are often caused by rocks or gravel which are kicked up by the tires of other vehicles. Chips (or rock chips) can often be repaired before they worsen. They should be attended to early on.
Pressure, Temperature, and Moisture—A Triple Threat
Pressure, temperature, and moisture are the three elements most likely to crack a windshield. Here we discuss them in detail. However, there are other contributing factors to windshield damage. Sometimes the problem is rooted in a manufacturing defect. In other cases, dirt and debris wedged between the layers of the glass can pry them apart.
How Much Force Is Required to Crack a Windshield?
Impact is the number one cause of windshield damage. It is responsible for the majority of rock chips especially. It can seem incredible that so small a thing as a pebble could damage a windshield of laminated glass. In fact, the amount of force required to break vehicular glass is approximately 20,000 to 24,000 pounds per square inch (psi) of pressure. That amounts to about 60 pounds of force.
Unfortunately, smaller objects like gravel on the road don’t have to pack a wallop of quite that size to do the deed because they have a smaller surface area. Projected pebbles essentially drill into the glass.
Other kinds of pressure can also crack a windshield. Dry windshield wipers can gouge or scrape your glass. If the windshield is already damaged, ordinary pressure like wiping it down by hand or the typical bumps and jostling of driving can make cracks and chips worse.
How Hot Does It Have to Be for a Windshield to Crack?
The way temperature can crack a windshield is a two-fronted battle. On one extreme, hot weather can soften the interior plastic layer of the windshield and make it easier to break. On the other hand, cold weather can cause the glass to contract, and if the windshield already has cracks or chips, contraction will exacerbate the damage.
The biggest temperature-related problem for windshields is rapid change. If a cold windshield is suddenly exposed to hot water or hot air from the car’s vents, cracks are inevitable. These commonly occur parallel to the bottom of the windshield and are likely to spread each time the temperature is uneven.
How Can Moisture Crack a Windshield?
Cars and trucks are meant for outdoor use, right? So how can moisture (which is everywhere outside) crack a windshield. The phenomenon is most common when damage is already present. If a windshield is already cracked or chipped, water can seep between the layers of the laminated glass and pry them apart. This is a bigger problem if the water reaches its freezing point.
Can a Cracked Windshield Shatter?
Windshields are designed to survive a lot of damage, but as we have discussed, they are not invincible. Each time a windshield sustains damage, it is exponentially more likely to take on more. This is because each crack or chip weakens the glass and overall structural integrity.
Unfortunately, when the strain becomes too much, a cracked windshield can shatter. However, even in such dramatic cases, the windshield is not likely to pull away from the vehicle’s frame. This is because of how windshield glass is constructed.
laminated glass, of which most windshields are made, is made up of two sheets of glass and a thin film of plastic in between them. Windshields are also secured to the vehicle with strong urethane adhesives. These are specifically designed to block out road noise and exterior moisture and to keep the windshield from shifting in the frame.
Even if the windshield doesn’t break inward, it is not wise to drive around with a cracked windshield. Any crack compromises a windshield’s structural integrity, and it is better to take care of any windshield damage before it becomes too serious.