Tag Archives: rock chip repair

Small Rock Chip – Big Problem!



Often drivers are lulled into a false sense of security by a small rock chip. They imagine that a small rock chip is somehow less likely to grow in to the dreaded crack that makes its way all the way across the windshield if left untreated. To begin with, most cracked windshields start with a small rock chip which later expands into a long crack. The crack may spread immediately, over night, or even in a matter of months to years. There is simply no way to tell when the damage is going to spread. Often customers inform me that the rock chip I am about to repair has been there for several years. I always tell them the same thing, which is that they have been on borrowed time, and very lucky at that. A rock chip may seem stable for a long time and then circumstances align causing it to suddenly break. Here’s some of the factors and physics behind what causes a rock chip to spread.

  1. Glass tends to expand and contract in the heat and the cold. Usually, the rock chip you can see with your eyes also contains several invisible micro cracks which extend further out. When the glass expands in the heat or contracts in the cold, already weakened by the impact of the rock, it may give way, cracking sometimes up to 2 feet or more.
  2. The impact of the rock hitting the windshield has removed a small piece of the surface glass, weakening the structural integrity of the windshield. Vibrations and bumps in the road can easily cause the chip to crack.
  3. Differences in atmospheric pressure can also cause a weakened windshield to crack. Often drivers report that a rock chip that had been on the windshield for months, suddenly cracked when they went into the mountains.
  4. Last, running the car heater or air conditioning can cause an unstable rock chip to crack. Like running a cold glass under hot water, or hot glass under cold water, the difference between the temperatures of the outer and inner layers of the windshield can cause the glass to shatter.

The size of the rock chip is immaterial. A tiny rock chip is just as likely to crack as a larger one. The same physics behind large rock chips are in play with smaller ones. That’s why I say that drivers are often lulled into a false sense of security when they have a small rock chip. I can’t count how many times I’ve heard the same story. It always starts something like this: “I had this little rock chip on my windshield that happened a few months ago and I thought, it was no big deal. Then I came out yesterday and it had spread to over a foot long. Is there anything you can do?” And of course, the answer is, “no”.

Rock chips are a pain in the neck no matter what size. My advice is to have it repaired immediately so it doesn’t become a much bigger, much more expensive, pain in the neck.


Rock Chip Repair & What To Expect

The windshield repair technician’s primary goal is to keep the damage from cracking further, resulting in the need for a more costly windshield replacement. A quality repair performed by an experienced technician should leave the windshield 100% structurally restored to pre-damaged condition. The cosmetic result, however, will depend on a multitude of factors.

imgres-11. The extent of the damage.

Typically, but not always, the more extensive the damage, the more visible the result will be. While glass can be repaired 100% structurally, it will usually repair 75-80% cosmetically. Fractured glass, even when repaired, will no longer refract light the way it did before it was damaged. Also, when the rock hits, it shatters the surface glass and propels it inward. This too, can lead to a more visible repair.

2. The length of time the damage has been there.

A rock chip treated soon after it occurs will almost always look much better than one that has been there for months or even years. The impact of a rock or debris that has caused windshield damage, leaves an open hole into the windshield. This entry point allows dirt, debris, and moisture to accumulate over time, and it is very difficult, sometimes impossible, to remove. I often advise customers to cover the rock chip with a piece of clear packing tape (the kind used to ship a package) immediately after the rock chip occurs. This helps to effectively keep anything from getting into the damaged area.

3. Miscellaneous Circumstances.

Often vehicle owners will try to treat rock chips with “home remedies” and do-it-yourself kits. Common home remedies include: Crazy Glue, clear nail polish, and Gorilla Glue. None of them work, and most often they ruin the windshield. The technician can’t get the glue out of the rock chip and so there is no way to complete the repair process. I call do-it-yourself kits, “one shots.” On a very superficial rock chip with no complications, the home repair kits will sometimes take care of it. You only get one chance (“one shot”) though with a do-it-yourself kit. If it works on the first try, you have lucked out. Most often, however, a rock chip repair requires several fill and vacuum cycles. Resin is injected and then air, dirt and debris is removed, and then another pressure cycle to add more resin, etc. Sometimes this procedure is repeated three or even four times before the repair is completed. Only professional windshield repair tools will allow for this. Windshield repair is not one of those things you can “just do.” You have to know what you are doing or you risk irreparable damage.

Often customers show up thinking that their primary goal is to save their windshield, and the secondary goal is how the windshield will look once it is repaired. After the repair, we often find that the cosmetic result was actually more important to the customer than saving the windshield was.

In short, what can you expect from a windshield repair? A technician should only accept the job if they feel the repair can be completed successfully. This means that the technician has determined that the result will leave the windshield 100% structurally restored. The customer should expect that small, superficial damage will appear approximately 75-80% better cosmetically once it has been repaired. That’s it. While larger, more extensive damage sometimes falls into that 75-80% range, there is no guarantee that it will. If the visible, cosmetic result of more extensive damage is not something you are prepared to live with, you are not a candidate for a windshield repair, You are more likely looking for a windshield replacement.

Hot Weather & Windshield Repair



Glass will always behave in a relatively predictable way. There are a few “enemies” of windshield repair. Extreme temperatures is one of them. Glass tends to expand in the heat and contract in the cold. The windshield is comprised of three layers, UV glass on the outside, UV glass in the interior of the car and a synthetic in the middle, laminated together to create a strong bond. When it is very hot outside, especially when the car has been sitting in direct sun, the windshield can heat up to well over 110 degrees F. More than likely, drivers will run their car air conditioner on a hot day and if there is a rock chip or a small crack on the windshield, the variance in the temperatures from the outside of the windshield and inside the car, can easily cause the damage to  grow in size resulting in the need for a costly windshield replacement. Here’s why: The outer layer of glass is expanding in the heat. The middle layer is fixed, and the inside layer is contracting from the cold air blowing from the air conditioner. This causes a certain amount of pressure, and to relieve the tension, the glass cracks. It is the same principle that cause a hot glass to shatter if it is held under cold water or visa versa. In the Winter, the same thing can happen, only in reverse. The outer layer of the windshield is icy cold and when the car heater is turned up, the inside layer begins expanding with the heat.

The take away from this, aside from having your windshield repaired asap when you have a rock chip, is:

  1. Avoid extremes in temperature. If you are still using the vehicle before you have a chance to have it repaired, try to park it in a shaded area, out of direct sunlight.
  2. Avoid using sun reflectors that are shiny. Shiny reflectors will shield the interior of the car by reflecting sunlight away, but they are also known to heat the windshield to temperatures that can easily cause a small rock chip to spread. Instead, use opaque, or satin-finished sun guards.
  3. If you are using your air conditioner, keep it on low, and keep the setting adjusted so that the air flow is focused mainly on your legs and not on the windshield.

-Simple tips that can help to save your windshield.

FREE Windshield Repair!

imgres.jpgMost of the time anything free is usually too good to be true. Not so with windshield repair. Almost all auto insurance companies will waive your deductible, and cover the cost of windshield repair with no negative effect on your premium. Here’s why they do so. Many policy holders have low deductibles, $0.00, $100, $200, etc. These people could literally claim a new windshield for just a small rock chip. This would cost the insurance companies a small fortune. So, the insurance companies offer free windshield repair to e everyone who has comprehensive coverage, regardless of the deductible. It appears as though they are doing you the favor by offering free windshield repair, but it is you doing the favor for your insurance company by being willing to have your windshield repaired instead of replaced. Only two of the large insurance companies, State Farm and Mercury, do not offer free windshield repair.

Here’s what to do:

  1. Call the claim number on the back of your insurance card and tell the rep you want to file a simple windshield repair claim. The rep will ask you two or three questions which are purely informational. Answer to the best of your ability. It does not matter how long ago the rock chip occurred, so there’s no need to get creative with your answers.
  2. Let the rep know if you have chosen a glass shop that you would prefer to use for the repair. Your insurance company will try to steer you into using one of their preferred shops, but you have the right to use whichever shop you choose. if you don’t have a preferred shop, they will assign a shop for you.
  3. If your chosen repair shop is included in your insurance company’s list of providers, they will fax your contact info along with the claim to the shop a moment after you hang up with your insurance company. The shop should contact you shortly thereafter.

There you have it – FREE rock chip repair.

Most vehicle owners are not aware that insurance companies provide free rock chip repair. It is not a perk that most insurance companies want to publicize. Free, anything, obviously effects their bottom line. Before paying out of pocket, typically for around $70, to have your windshield repaired, contact your insurance company to ask about free rock chip repair. -And if you are in the San Francisco Bay Area, by all means, let them know that you would like American Glass Repair to do the repair. We would appreciate that.

Don’t Do It Yourself!

I see this all the time. Some one shows up at my garage for a windshield repair and within 5 seconds, I can tell that they’ve attempted to repair a rock chip by using Krazy Glue, Gorilla Glue, clear nail polish – you name it – whatever else they think makes sense at the moment. The trouble is, nothing will work except acrylic resin, properly used by a professional. I’ll ask, (already knowing the answer), “Have you used any type of product on the rock chip trying to repair it yourself?” Almost always the customer tells me no. I don’t press the issue, even though I can clearly see that something was used on the damaged area. At that point, the customer really needs a rescue and not a repair. Unfortunately, once a product like Krazy Glue has been used on a rock chip, there is no way to repair it properly. The glue gets into the rock chip and hardens, preventing the acrylic resin from doing its job. Only acrylic resin can be used to repair windshield damage. Anything else will ruin the windshield and eventually result in the need for a costly replacement. Krazy glue may support the weight of a grown man, as seen in the photo, but using it on a windshield is one quick way to end up in a glass replacement shop. images

The best advice is, Don’t do it yourself.

To Rain-X or Not To Rain-X?

Image… That is the question

Rain‑X® Original Glass Treatment claims to “dramatically improve wet weather driving visibility. Simply apply the treatment to exterior glass and watch the raindrops fly off your windshield while driving. Rain‑X helps improve visibility by repelling rain, sleet and snow.” 

I use Rain-x on my own vehicle windshields. It does work as claimed. With regards to windshield repair, Rain-X presents a problem. The synthetics used in the composition create a sort of waxy film on the surface of the windshield. When a rock hits the windshield, the surface glass is propelled inward by the force. Rain-X treated glass finds its way into the rock chip which makes it very difficult for the acrylic resin used in the repair process to uniformly fill the damaged area. I’m not suggesting that this is a reason not to use Rain-X. Rather, it is important to tell the windshield repair technician ahead of time that the windshield has been treated with Rain-X so the technician can take measures to dissolve the Rain-X before attempting to complete the repair. Dissolving Rain-X is as simple as using a dry-tool, which most windshield repair technicians already use for drying moisture before filling a rock chip. Filling a repair without dissolving Rain-X first will result in a cloudy appearance and a rock chip that has not been uniformly filled. 

I recommend using Rain-X products. They are terrific and they work. Make sure to tell your windshield repair technician that you have used these products before the technician begins the repair.


Not All Windshield Repairs Are The Same

windshield-repairNot all glass shops are the same. You owe it to yourself to do the research to find a glass shop that meets high standards. To begin with, when filing a glass repair claim with your insurance company, ask them to refer you to a “tier one” shop. Here’s why that makes a difference. With exception of a few, most insurance companies use glass networks who contract glass repair shops and technicians to do their glass repairs. In fact, most often once you tell the initial representative at the insurance company that you are filing a glass repair claim the next person you are transferred to is not even an employee of your insurance company, they work for the glass repair/replacement network. The network has contracts with hundreds of glass shops and technicians, all who have varied levels of expertise and experience. The networks need to match up your claim with a technician in your area based on your zip code. This is where requesting a tier one shop / technician makes a difference. Often, tier one service providers are  rightfully busy, because they are in demand. If the network can not find a tier one shop to do your repair they move down the list until often your repair is being handled by someone with little to no experience at all. Ask yourself one question: do you want your windshield repaired by a glass technician with little to no experience? The answer is obvious, no.

Search out reviews on Yelp where you will see what others are saying about a shop the network has recommended. if the reviews are not primarily 4 and 5 stars let the network know you prefer another shop. By law, you have the right to choose whichever glass shop you want to use to do the repair. Networks will often engage in an illegal practice known as “steering” where they funnel business primarily to their own shops and technicians that are in fact working directly for them. It is important to use a shop that is independent of the network so you know the only criteria used for the referral is the work the shop does and not any financial arrangement the shop has with the network.

Windshield repair is a one shot deal. By that I mean that once a rock chip or a crack has been repaired, there is no do-over. A bad repair, can not be re-repaired to make it better. Getting it right the first time is essential. To do this, you need to have a professional technician with a proven track record do the repair.