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.
Now that we have got 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 filling those spaces gradually until reaching the vicinity of the tip. After resin has finished filling, the technician cures the 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.