How Does It Work

Written by Genny Clark

Maybe it has never occurred to you that chipped or cracked glass can actually be repaired just like a flat tire or a hole in one of the walls of your house. Rather than buying a new tire or a whole new house, just like glass, it would be more cost effective to simply repair them, when possible.

Repairing the windshield, or even the side and back windows of your car, is a fairly quick and seemingly simple job. However, this is only due to the refinement of the tools and technology necessary to do it. Properly fixing a crack or chip in the windshield of a car is a technical and precise craft with important ramifications. It is important to have it done the correct way, since your safety depends on it.

Laminated windshields

Windshield repair is possible because the front windshield of a car is laminated. A laminated windshield is two pieces of glass with a layer of vinyl between the two. This glass-vinyl sandwich is bonded by applying heat and pressure in an oven called an “autoclave”. When a rock or other object strikes your window creating a chip or crack, this structure of glass/vinyl/glass will absorb some of the strength of the impact and can help to prevent the rock from going through the glass or even past the first layer. By reestablishing the integrity of the weakened area (the crack), the windshield can be restored to full strength and safety because there are still two solid layers fully connected to the first layer.

How a windshield is fixed

A crack is restored by using a special resin, a type of acrylic that bonds to the glass. First, though, a vacuum is applied to the cracked or chipped area to take all the air out of the holes which takes all the force off of the weakened portion of the glass. This way, when the resin is inserted into the crack there will be no additional pressure causing the chip to widen or the crack to spread. The resin must specifically match in strength, tint, and light refraction with the glass.

Once the resin is injected, it can be cured using a UV light which must match in wavelength according to the resin in use. This is much better than letting the resin cure by natural UV light as the sun will not result in as strong a bonding. Also, in some instances the weather will not be sunny, in which case the special UV light is not only an advantage, but a necessity. Once the resin has been applied and the cured with the UV light, it is polished smooth. Usually, at this point the crack or chip is hardly noticeable, if it is noticeable at all.

Not every windshield can be fixed

A windshield can only be fixed if it falls within certain parameters. Most of these stipulations are to ensure the repair will last and to provide reasonable safety by reestablishing the integrity of the windshield.

Location

The chip or crack cannot be directly in front of the driver’s view and cannot reach to or start from the edge of the windshield.

Size

Most repair services start shying away from a repair when the crack is longer than 6 inches. Also, the crack cannot spread in multiple different directions as it goes as this will prove to be structurally too weak to provide any sort of guarantee or safety. Also, if the chip is larger than a 50 cent piece it will be harder to find a service that will repair it.

Extent

It is important that the crack or chip is not too deep. If it goes clear through the first layer of glass and into the vinyl layer beneath, the integrity of the windshield can be severely compromised. This is especially pertinent if the crack has been exposed to the elements for a length of time allowing chemicals and water to enter between the glass layers damaging the vinyl.

By using the correct equipment a windshield can be fully restored to its original structural integrity. This is important as anywhere between 40%-70% of the strength of your car’s frame is directly dependent upon the windshield. In the event of a rollover or high impact crash, the windshield can be the difference between life and death.

Not only is auto windshield repair pertinent to safety, it also affects the economics of your wallet. It is about ten times cheaper to have a windshield repaired than replaced. Some insurance companies will even waive the deductible and pay for a repair to prevent paying the extra money to have it replaced.

Auto glass repair has been around since the 1970s and is a fairly refined yet simplified procedure. Whether starting your own glass repair business or simply taking advantage of the technology to have your windshield fixed, knowing a little about what goes into fixing a cracked or chipped windshield can take you a long way towards safety and savings.

Rather than buying a new windshield it would be more cost effective to repair it if possible. Therefore, knowing more about auto glass repair can come in handy.