I have been in the auto glass business for about five years now, and I get asked every day "can I just get the windshield repaired? I really don't want to pay for a new windshield." Here are the rules I have to follow:
1. How long is the crack? If it is more than an inch, then it really needs to be replaced. You see, to repair a rock chip I have to have my technician drill into the windshield. He then injects a resin and cures it with an ultraviolet light. It generally takes about 30-45 minutes to get it done. The more I drill into the windshield, the more likely the windshield is to crack even more.
2. Where is the rock chip located? If it is in the driver's line of vision, it is not a good idea to repair the rock chip. Since I have to drill into the glass, a tiny amout of the glass is removed from the windshield. This leaves a flaw in the glass. Not a problem when it is not in the driver's line of vision. When it is in the driver's line of vision, the slight flaw in the glass can catch the sunlight, flare, and interfere with your driving.
Why do some people say they can repair a crack longer than an inch? They do sell kits to repair up to 12-inch cracks, but in general they have a high failure rate.
How long does a rock chip repair last? I tell people they can last 10 seconds or 10 years. Glass is unpredictable that way.
How many chips can I get repaired? In general, the insurance companies will cover up to three chips; after that, you really need a new windshield.
Will my insurance company waive the deductible for the rock chip repair? It varies by company; you need to call and ask.
Will I be able to see the rock chip after it is repaired? Again, glass is unpredictable; sometimes you can see the repair, sometimes it is hard to see, and sometimes it seems to fully disappear. This is not something the technician can control; it depends on the glass.
Can I repair the rock chip myself? They do sell kits for this, but if you are not a handy person, I would call an expert. If you try to repair the chip, the crack can spread, and then you WILL need a new windshield.
Can I repair a rock chip again? No; once a rock chip has been repaired, it cannot be repaired again.