Have you ever wondered why windscreens tend to crack while car windows shatter and fall apart?
The glass used in cars for windscreens and windows are both forms of safety glass, but they differ slightly for good reasons.
Depending on where the glass is being used in your car, it is prone to damage from different sources.
This can include vandalism, a car accident, rocks kicked up from passing traffic and other sources of accidental or intentional damage.
Whilst the front windscreen is made up of two layers of laminated safety glass with a plastic layer in between, the side and rear windows are made from single layers of safety glass.
Car Windows Safety Glass
Safety glass is constructed in such a way that it completely shatters into pebble-sized pieces after a strong impact on it. These pebble-sized pieces of glass are much less sharp than typical broken glass fragments.
This safety glass, when broken, does not form pointy shards. This makes the risk of getting hurt inside the vehicle much lower than if it was not used.
How This Safety Glass is Made
The safety glass used on car windows is manufactured through the process of tempering. This involves heating the glass to a high temperature then cooling it rapidly.
This is why this glass is also known as tempered glass.
The outside of the glass is thus put into a state of compression whilst the inside is put under tension. This process is what ensures the glass shatters on impact.
The tempered glass on windows are also important during accidents as they are easy to break in the event of an emergency escape from the car, for example, if you are stuck inside the car.
Laminated Windscreen Safety Glass
On a windscreen, the two outside layers are curved glass which are heated to fit a mould, then cooled down rapidly. Just like the safety glass for car windows.
The difference now comes where the two layers of curved glass are placed around one layer of plastic that is all bonded together.
Because of this tough layer of plastic in between the glasses, when your windshield gets hit by an object, the glass tends to stick to the plastic layer rather than breaking off into shards.
By not allowing the windscreen to shatter into many tiny pieces but keep a solid structure, this adds structural strength to the vehicle in an accident.
This a a structural modification that ensures the safety of the car occupants in the event of a crash. In turn, this helps the roof not to collapse as the windscreen holds the roof in its position.
Therefore on impact, the plastic layer on the windshield allows for a crack from the pressure rather than allowing the entire windshield to shatter, becoming a hazard or danger to the passengers.
Do you have a damaged windscreen that you need repaired or replaced in Sydney? Contact Metro Auto Glass now for a free quote.