For most automobile owners, changing oil and doing routine maintenance checks are important aspects of keeping the vehicle healthy. When the car manifests signs of problems, the driver would usually make sure it is corrected immediately to avoid more costly repairs later. But one thing most car owners neglect, but should not, is the windshield. Although the windshield does not belong with the ‘mysterious’ underhood components and seems to be transparent in its use, its importance cannot be understated. As with any car component problems, windshield damage should be repaired immediately.

Many people doubt the value of a chip repair. Paying fifty bucks for a chip repair that is barely the size of a nickel seems unreasonable. However, most do not realize that the windshield is very fragile to internal stress. It may look impenetrable, but when subjected to road and temperature stress, the chip can easily become a crack. Searching recent forums, an Acura owner’s tolerance of “an annoying little rock chip [had] finally become a long streak across the middle of [his] windshield.” (1)

Your Windshield

As with all things, let’s begin with the basics.

Windshield glass is a type of laminated glass. It consists of two layers of special composite glass with a laminate in between the layers. The laminate usually is made from a form of vinyl plastic, which is in simple terms, a very strong plastic. The laminate acts as a sticking board for the inner and outer layer of glass, which serves to hold both layers together and provides a surface in the event of shattering for glass fragments to adhere to.

Sidenote: Some windshields are tinted the tinting actually comes from the laminate layer, not from the glass layers, as common misconception suggests.

A black frame, referred as the ‘frit’, lines the outer edges of the windshield, commonly 2-3 inches wide and even wider on top. The frit protects the urethane molding (generally speaking, glue that bonds windshield to car) of the windshield from the sun’s ultraviolet rays. Without the frit, the urethane would melt and cease to hold the windshield to the body frame. This is what happens with rear-view mirrors that are incorrectly installed they fall off the windshield after the adhesives melt in the sun’s heat.

Functions of Your Windshield

Windshields play essential roles in vehicle safety and drivability. First and the most apparent function of the windshield is blocking wind and airborne debris from you and providing a clear perspective of road conditions. This is more of a drivability issue. The next two functions are safety-related, especially during an accident. In a frontal collision, two safety features of the car minimize impact damage to the driver and passenger: SRS Airbag and seat belts. In order for the airbag to deploy properly, the windshield needs to be in place. It stops the airbag from deploying upwards and redirects the direction of inflation toward the driver. In a rollover, windshield serves dually to prevent the roof of the car from collapsing and the passenger from having any body parts hanging outside the car. This issue is more pertinent with side windows, where loose body parts will dramatically increase fatality rates.

An improperly installed or cracked windshield will jeopardize your safety. One, the windshield may crack up and eventually lose integrity and shatter. Two, during an accident, the windshield will fly apart on airbag deployment with shards of glass spewing all over the place. And the airbag will be less effective. Third, on a rollover, compression stress will first stretch the crack from end to end and then finally break the windshield. Flying glass shards are very sharp and dangerous.

How Your Windshield is Installed

Ok, are you still following me? In the above sections, I have mentioned windshield structure and function. This section will cover windshield installation. The next section will tell you about windshield stress areas that dictate how likely a chip or crack is going to develop further.

Windshield placement is a highly robotic and computer-controlled process in the assembly line of automobile manufacturing. Computerized alignment and placement procedures ensure that both molding and windshield are accurately fitted. Preparation of the car frame provides a clean surface to which the windshield could bond. Furthermore, there is ample time between windshield installation and the end of the production line for the molding to cure. Because of these exacting processes, the quality that comes out the factory is the best.

For aftermarket windshield installation, getting rid of the original windshield properly is foremost to a good replacement. The correct installation techniques require removal of the old molding and lower windshield cowl panel. Subsequently, the glass is cut out, leaving around 1/16″ of urethane bedding. The channel area, where the urethane adhesives bond, should be primed to inhibit rust formation. Rust formation will eventually weaken the bonding of the windshield to the car. After placement of the windshield, the car should be given from 1-24 hours to cure, depending on the adhesives used.

Stresses the Windshield Endures

Whether your car is parked, speeding east on Highway 60 or turtle-ing in the morning rush hour on I-10, your windshield endures many abuses: temperature changes (most notably night cooling and day heating,) road vibrations and car body frame shears, and road debris.

Because glass expands and shrinks at a slower rate than the metal body frame it is located in, during temperature changes, for example a rise in ambient temperature, the expanding metal pushes in on the sides of the windshield conversely, a decrease in the ambient temperature exerts a pulling force on the edges of the windshield.

Now imagine, in addition to temperature stress, the constant pulling and pushing of the windshield from the body frame absorbing road impact. A stress gradient exists within the windshield. The highest stress occurs around the edges and lessens gradually approaching the center point of the windshield.

Sidenote: In the modern windshield with curved edges to allow for a panoramic view, better aerodynamics and stylish look, the stress is even greater.

So far so good…Then a rock hits the windshield and creates an opening. Usually the windshield could distribute temperature and vibrational stress to its neighboring glass molecule. Now, however, tension would accumulate along the edge of the crack until it travels down to the border of intact and separated glass. The extra tension causes the borderline intact glass to separate, since it is the next weakest point and would continue until something is done about it.

Stress gradients correlate directly to the likelihood of a chip or crack developing further. A stone break in a high stress area, i.e. the sides, is more likely to evolve into a crack. Cracks that start from the edges usually travel to the center of less stress, just as water flows from high pressure to low pressure. Depending on shearing forces the car body exerts on the windshield, the crack may actually travel in different directions.

Value Windshield Chip Repair Services

After you read this article, we hope that you have a deeper appreciation of the value of the windshield chip and crack repair that our service sector provides to you. By repairing stone breaks and cracks when repairable, we save you time and expense and give you quality. Cars retain their originally fitted windshield, which is ever more important in new models where windshield design have reached the stage that correct replacement is paramount to ensure a snug fit and prevent stress cracks from developing. (Stress crack can occur even without external damage, especially if the windshield is not designed to fit on certain car models.)

Properly done repairs will enhance the strength of the windshield, reduce optical distraction, restrict damage area and maintain a smooth surface for wiper operation.

Call Prestige Auto Glass today to get your windshield fixed, we offer FREE Mobile service.

Credit: Goober’s Windshield Repair

Before we begin with the repair process, we should evaluate when and why you should have your windshield repaired. You should always have your windshield repair at the first damage it takes, when it is still a small ding. When you repair that, at a considerably lower cost, the chip will fill in, restoring windshield strength and prevent further cracking. If you leave the chip in the windshield, sooner or later it will crack open, developing into a full length crack. The problems with a crack are that it weakens the windshield substantially, is harder to hide cosmetically even with repair, is easier to get contaminated and that not everyone can perform crack repairs. Crack repairs require another set of equipment different from chip repairs.

In this article, we will be repeating some information also found in our article on fixable chips and cracks.

Chip Repair

A chip, or more commonly called ding, is a small break caused by object impact from stones and projectiles. The break can be structurally classified as bullseye, star break, and combination. Most other structural breaks are derivations of these three basic types.

In order to properly fix chips, several steps must be followed to ensure the best repair. Beginning with preparation, the technician cleans the surface of the damaged area of loose glass shards. Then the center of the impact point is opened up through drilling to facilitate resin injection. Depending on the type of break, the chip may be further “tapped” to create a reservoir in the glass through which resin can flow easier into harder-to-reach spots.

Now that the chip surface has been prepared, the technician aligns the injector head to the chip entry point, first vacuuming the air out of the break and then following through with resin injection. When the chip has filled, under a curing light, the resin in the chip begins to solidify, bonding the cracked windshield together. The remaining steps involve curing additional layers of resin onto the chip impact point to ensure a smooth surface and polishing to protect the resin from chemicals in the air and wiper washers.

Prelude to Crack Repair

Crack repair deserves a little more attention. Before you consider a crack repair, please ask yourself the following questions:

What type of crack is it?
How long has it been there?
Where is the crack?
What are you trying to achieve with a crack repair?

If the crack is a single long crack (one impact point, one crack) and under 24 inches, a crack repair is feasible over a windshield replacement. If there are multiple single long cracks in different locations, then you also need ask yourself what you want from the repair. If the crack has many legs (one impact point, multiple cracks) then you should eliminate repair from your considerations and go directly to replacement. There has been too much structural distortion to properly repair that. Lastly, if the crack is a stress crack, meaning that it developed without an external break, then either your windshield is defective or your car frame has somehow warped that an abnormal stress pattern is exerted on the windshield.

Next, after a rigorous process of elimination and you determined that your crack belongs to those fixable single long cracks, you should also know how long the crack has been there. Cracks one month old are repairable. Over that you should consult a repair technician. Factors such as the number of car washes, types of car washes, driving environment and overnight parking locations will affect the cleanliness of your crack.

The answer to the next question is basically a ‘yes’ or ‘no’ to repair.

Q: “Where is the crack?” (Should I repair the windshield?)
A: “Over the driver’s primary viewing area.” (No.)
A: “Somewhere else.” (Yes.)

Lastly if you want to have a perfectly transparent windshield, you should opt for replacement. Repair will improve it cosmetically but sometimes and at some angles you will be able to see a thin line and a little bit of visual distortion, but not enough to affect your driving ability. I recommend you to get a replacement if you have multiple single long cracks, unless you care less about seeing visual blemishes than paying top dollars for a good replacement.

Crack Repair

Now that we have gotten through the administrative material, let’s get to the point.

Crack repair begins with creating a tip for the crack. The tip serves as an end point for the crack in other words, you can imagine the tip as a heavy weight anchor that the crack is tied to. Filling the tip in separately, the technician then proceeds to inject resin into the crack starting from its impact point. Then slowly and methodically the technician moves the injector along the crack path and fills those spaces gradually until reaching the vicinity of the tip. After resin has finished filling, the technician cures the resin.

Resin

One very important element of repair is the resin. Resin viscosity rating correlates to its strength. For chip repairs, the resin viscosity is lower than the resin viscosity used in crack repairs. The reason being that resin used for chip repairs need to be versatile to go into nooks-and-crannies and less for strength, since the structural damage is very small. For cracks, there are no small spaces to wedge into and it is very important to have stronger resin to fully bond the crack together.

Curing Light

Curing light plays a crucial role in repair quality and time. The right curing light only will properly cure the resin in a shorter time span. This enables the vehicle owner to assume normal usage of the car right after the repair.

Windshield repair is a simple process all it takes to get a quality repair is knowing what and when to repair and having the right technician.

Credit: Goober’s Windshield Repair

Repairable Breaks – How a Repair is Done

Bullseye
Not larger than a quarter coin

Half Moon
Not larger than a quarter coin

Star Break
Not larger than a credit card

Combination
Not larger than a credit card

Crack – No longer than 24″
Cracks worthy of repairing are ones that are relatively clean. If the crack is less than one month old, and has not been driven in really polluted or dirty areas, it can be repaired. Otherwise, the repair technician will balance other factors to determine if the crack repaired will be worth the time and expense. Multiple single cracks may not be worth repairing, depending on your situation. Complex cracks are rarely worth repairing.

The optimal repair environment is under shade with luminescent light bulb overhead and windshield temperature around 72-74 degrees F, typically in a garage setting. Results are best when the chip or crack is new and clean.

Don’t wait for your chip to became unrepairable call Prestige Auto Glass today to schedule an appointment.

Credit: Goober’s Windshield Repair

In both glass layers
Too much structural disruption has formed in the windshield.

In the inner glass layer
The repair would be done unfavorably against gravity.

In the driver’s primary field of vision
Chips that are greater than a quarter in size with a center impact hole of greater than 3/16″ and within 4″ of another chip repair would not be repaired. These guidelines are followed to ensure minimal visual distraction and distortion to the driver.

Three or more long cracks legs
Too much structural integrity has been compromised.

In areas of value-added features (i.e. defroster wires)
Repair may negatively affect the functions of the feature.

Intersecting multiple edges cracks
Too much structural integrity has been compromised.

Breaks with a center impact hole greater than 3/8″
Too large for any repair to be done properly.

Breaks with visible impurities that cannot be removed
The impurities may impede resin flow and complete filling of the cracks. It prevents quality repair and is also visually distracting.

Prestige Auto Glass, College Park, Maryland adheres to National Windshield Repair Association guidelines.

Credit: Goober’s Windshield Repair

WINDSHIELD REPLACEMENTS  STARTING OFF AS LOW AS 99*

CHIP REPAIRS STARTING OF AT 60*

CALL US AT 301-614-8500 TO SCHEDULE YOUR APPOINTMENT!!