Auto Parts,  Cars

Should I Repair a Windshield Chip?

Car windshields can be expensive and inconvenient to replace. When my car window had a crack in it about 25 years ago, the window repair shop was able to repair it without replacing the window. Now there are several do it yourself kits you can use to repair your window yourself.

You should always repair a chip in a window as soon as you can. The chip can start to crack and the crack can get bigger until you need to replace the entire windshield. If you have a chip that is just a scratch in the glass, it is important to repair it if it is distracting, but it will not cause the glass to crack, so it may not be necessary.

As I drive I feel confident that my windshield offers a clear view of the road and traffic. When I've had a crack and chip, I felt both like I could just ignore it, and that I better take care of it soon before it gets worse. We'll take a look and see what action you can take for various chips and cracks.

Why do Windshield Chips Occur?

The windshield is a barrier between you and the weather. It also can stop a host of other objects so that you stay protected as you drive. 

Windshields use hardened glass, so that if a large object hits it, the glass will shatter into tiny piece that won't hurt like shards would. In addition windshields stick together when shattered. 

Windshield glass is made of three layers. A layer of glass on top, a laminate cellulose layer, and a bottom glass layer. The glass sticks to the middle layer and if it shatters it will stay together in one piece.


A chip can go down to the middle layer as the top layer of glass is hit, usually by a rock or pebble. Glass chips occur because the glass can handle a certain amount of pressure before it gives. When rocks hit the glass at fast speed, the glass wants to distribute the impact into the area surrounding the impact site.

You'll see all sorts of impacts types that tend to for a circular pattern starting at the impact site. If you've ever cracked an egg, it can crack nicely and split in one line, or kinda get crushed with all sorts of cracks everywhere around the impact area.

The same impact results on an egg, apply to glass in some ways. A fast sharp hit will quickly crack and distribute the force in a certain way, while a slower but stronger force would cause a shattering effect.

Why is Repairing a Chip important?

Glass has a certain amount of strength and can take up to a certain amount of pressure before it cracks. I had a friend when I was a teenager who crashed a motorcycle into a car. He flew into the windshield and it shattered, but he didn't go through. (He broke a limb but was OK. Thank goodness for helmets.)

When a chips occurs, it may seem to be fine for months, and your wondering if you even need to get it fixed since nothing is happening.

Two things occur with chips. One is that they will normally grow over time. Bumps and stresses to the window will grow tiny cracks that have already formed in the chip, but that may not be visible, and they start to expand.

Second, chips, even though they are small, will compromise the strength of the windshield. Think of the example of an egg that just has a tiny crack. Less pressure is needed to crack it even more, but if it was whole, the egg can with stand a great amount of pressure depending on where pressure is applied.

On the other and if you placed tape or nail polish over the crack, the crack would be reinforced. The egg would then be able to continue to take greater amounts of pressure.  

So when you see a chip in the glass, just imagine your repairing it is like reinforcing your windshield to prevent further cracking and giving it enough to strength to function as a whole again, just like the egg.

How to Repair a Chip in the Windshield?

A quarter or smaller sized chip should be fairly easy to repair with a do it yourself windshield repair kit. Each kit has instructions on how to fix the crack properly. Read the directions thoroughly to make sure your results look good and not half baked.

While you want a clean window, make sure not to get any water into the chip or cracks. Brush away any debris from the chip if needed. Some kits will come with a push pin to use as a tool to dig out any of the loose glass from the chip.

Gather all the materials you need and decide where you want to place your car. Many people prefer the shade because the windshield should be warm, not hot. If it's too cold or too hot out the resin will be difficult to work with. Try finding a warm temperature to work in.

During the repair try not apply pressure around the chip as this may increase the size of the crack in the glass. If you are having difficulty seeing what's happening as you work on the chip, try placing a piece of paper or a post it note on the inside of the windshield so you can see the chip better.  

If you are finished with the repair I would recommend letting the resin sit for a half an hour longer than the instructions say, just to be sure the resin has cured. Then you can remove everything and scrape the resin flush with the glass.

If things didn't turn out too well, it's a good idea to try again if circumstances permit. You can get the rough surface to become smooth or see if you can get any areas that may not have gotten enough resin. 

Taking your time will help you get a more professional look and make the difference between a cloudy mess and a clear almost unnoticeable professional job.  

Is a Windshield Scratch the Same as a Chip?

If you have a scratch in your windshield it could be from a small rock, your windshield wiper, or placing an object on the windshield that was sharp. 

Scratches tend to be fairly shallow and will not impact the structural integrity of the windshield. They do not penetrate to the laminate layer or create cracks in the glass. They can be distracting, like a chip, and cause drivers to drive unsafely.

If you have a scratch that impacts your driving it needs to be fixed right away for your distraction free driving safety and that of others. A buffing compound can be used on many shallow scratches to effectively remove them.

If the scratch is deep, some people report that using a chip repair kit helped them remove these scratches well. Although this method may take some trial and error, it is worth it if you can have a clear windshield.​

When not to Repair a Chip in a Windshield?

If you have a chip that has cracks that span more than two inches you may need to get professional help. A professional may be able to fix cracks longer than 2 inches, but not all cracks. 

There are several reasons why you might want to replace your windshield. Below are some reason that you may need a new windshield.

  • One reason is if there is a noticeable mark on the window in you line of sight while you drive. For example, If you repaired a crack but you still see a cloudy spot where the repair was done that distracts you, then getting a new windshield would be helpful for your safety and others on the road. 
  • Another reason to get a new windshield is if your chip has spread too wide and is too difficult to repair. It will be much safer for you if you have a new intact windshield that can absorb an impact if needed, versus a windshield that can no longer absorb as much impact.
  • A third reason to replace your windshield is if the crack extends to the edge of the windshield. A crack extending to the edge compromises the ability of the glass to absorb an impact. The edges absorb part of the impact from objects and a cracked edge would never be able to be hold the windshield together under certain pressures, even if it was repaired. 
  • In addition if your windshield had several chips, that each have cracks, you'll need to decide if DYI repair epoxy will work fine or if the glass has become too compromised and needs to be replaced. 

A new windshield can cost a lot but if you check your local windshield repair shop, it might be very reasonable. Some start about $200, but for a luxury car windshield you would likely end up paying much more. 

Avoiding Chip Repair in the Future

Road rash is very common for cars to have. You'll notice little chips in the paint in the front of your vehicles hood and grill area. Although rocks may hit the windshield, they are thrown into your car with a low enough force that they do not leave much of an impact on your windshield. 

That's why bigger rocks are important to look out for. They are thrown with more force and have a bigger impact on your window, often causing chips and cracks.

Be aware of trucks and hauling vehicles that are carrying cargo such as small rocks. Sometimes these vehicles lose pieces of their cargo through small openings. If you see rocks spilling from a truck, carefully move to avoid getting hit by a rock.

You might try passing them or moving over next to them. Some people like to slow down and get far enough back so the rocks don't hit their car. 

If you do get hit by a rock, your insurance may cover the cost of repairs, especially if you need to replace the windshield. If you can safely take down the license plate number do so, but never drive and write or take a photo. Wait until it's safe to copy a license number and then refer to it when the insurance company asks about the other vehicle.   

Pro Tips for Repairing Chips

If you are a professional at repairing a chips in windshields, you'd have some tricks you've learned along the road. Lets take a look at what some professionals do.

  • One trick professionals use is to use a tiny drill to create a path for the resin to go when fixing a chip. They drill down into the glass almost to the laminate layer and then stop. If you reach to laminate layer, then it's OK but you shouldn't go any further.
  • Professionals also tend to use a curing infrared light. This helps the resin to harden at a specific rate. The sunlight will also harden the resin, but it may take longer if your car is not in direct sunlight.
  • When you are filling chips and cracks, you may need to be patient by either waiting for the pressurized resin to fill the area, or you may decide to add a bit of additional pressure. Pushing the resin into the chip with a bit of extra pressure may be OK but could also cause problems. This is were experience comes in handy. 

Conclusion

Driving with a chipped windshield is not safe and it should be fixed for your safety and to save money on buying a new windshield. Most chips can be fixed at your house by yourself. If you have a chip or scratch on the drivers side that impacts your driving, be sure to fix it as soon as possible. 

Repairing your windshield shouldn't be to much work, and it will feel really great when you have a clear strong window to keep you safe and distraction free.