Do Windshield Repair Kits Work?

One of the most annoying things that can happen to your car is getting a crack or chip on the windshield (or windscreen, depending on what you call it where you live).

Even if you have full insurance cover that allows for windshield replacement at no cost to you, there is still the hassle of getting your car to the glass specialist, picking it back up again, dealing with the insurance company etc.

You also might not have windshield cover in your insurance policy, meaning that you are left facing a hefty bill for repair or replacement.

Another scenario is that you know you can get replacement done under insurance, but you are away on a work trip or vacation and need something that will help you to get your car home (this happened to me recently, and is the inspiration for this article and my more detailed Rain-X windshield repair kit review). You just need a temporary stop-gap measure to last you until you can get a proper repair done.

For classic cars, one of the reasons that you might choose to use a repair kit is that it can be tricky to source a replacement windshield. Auto glass specialists will tend to be able to find windshields for popular, modern models of car, but for some older vehicles you can be waiting a long time (it’s not exactly the same scenario, but the rear glass on my old Fiat Stilo Abarth was smashed in what I believe was a bungled burglary attempt. It took over three months for a new rear windshield to become available, and another month to get an appointment to get it fixed!)

Whatever the reason why, one popular choice is to use a DIY windshield repair kit.

But do windshield repair kits actually work?

In this article we are going to look closer at whether or not DIY windshield repair kits are a waste of money or if they actually work.

What Are DIY Windshield Repair Kits?

Long story short, most DIY repair kits contain a special type of resin that fills in the crack/chip on your windshield.

When this resin dries (or “cures” to use the technical term) it bonds with the surrounding glass and also goes clear, so you can see through it like normal glass.

The kits contain everything needed to do a DIY repair, including the resin and other tools required to get a better outcome.

Where To Buy & How Much To Pay?

Windshield repair kits are fairly inexpensive. You might pay anywhere from $10-30, depending on where you buy from and the urgency with which you need to get it (i.e. if you are forced into buying from some small town automotive store, then you might need to pay more).

Amazon has a great range of repair kits, which you can see for sale here.

If you need something right now, then your local car parts store is probably the best bet. Many hardware/DIY stores seem to stock these products as well.

Is A Repair Kit Right For You?

Different repair kits seem to come with different recommendations and requirements, but at a high level, you can use a repair kit in the following circumstances:

  • The chip/crack is only one layer deep – Most windshields consist of two layers of glass, with a layer of plastic sandwiched in between to improve strength and safety. If your chip/crack has somehow gone through the first layer of glass, and the plastic into the inner layer, then you won’t be able to repair the problem.
  • The chip/crack isn’t too big – Look at the instructions for the specific kit you are looking to buy to see what constitutes “too big” for the kit, but a rule of thumb is that any chip larger than a small coin is going to be hard to repair. Any crack longer than about 12 inches is also too big to repair.
    • The smaller the chip/crack, the easier it is to repair.

My Experience

As I mentioned in the intro to this article, I recently used a windshield repair kit on a trip to tide me over while I drove my car back home.

I was on holiday, and wound up with a decent crack (that was spreading into the key vision area) owing to someone flicking up a stone on a drive across a twisty piece of gravelled road.

I purchased a Rain-X windshield repair kit from a local store – read my full review here for info and pictures – and attempted a basic DIY repair that would hopefully get me home without any spreading of the crack.

The outcome of the repair exceeded my expectations. Not only did the crack not spread any further, it largely disappeared altogether.

Considerations

Looking at my own experience, talking to others who have used these kits, and reading reviews and info online, there seem to be a few key considerations that need to be made before you look at using a DIY windshield repair kit:

1. Are your expectations reasonable? If you are expecting ‘as good as new’ from your windshield repair, you will probably be disappointed. I was still able to make out some faint crack lines, for example. You will not be able to achieve an outcome as good as what a pro can do, and certainly not to the same standard as having a new windshield!
2. Is the chip/crack small enough to actually be repaired? The larger the chip/crack, the harder it is to repair. Be realistic about what can be achieved.
3. Can you follow the instructions? The instructions for these kits are fairly precise, as you need to ensure you are getting the air out of the chip/crack etc. If you can’t follow the instructions, then you are unlikely to enjoy a satisfactory repair job.

If you can answer ‘yes’ to those questions above, then a DIY repair kit might be a good option.

Nothing Lasts Forever

One thing to bear in mind is that your DIY repair might not last as long as you like.

I can’t comment on this from personal experience. My repair only needed to last about a week (I had already booked the car in for a full replacement windshield before even using the Rain-X repair kit, so I knew how long it had to last).

Many people seem to go happily about their way with a DIY repair lasting months, even years.

However, I have seen plenty of complaints of the repairs giving way after time, often when another stone or other object hits the windshield. Another contributing factor can be weather extremes, for example freezing cold weather causing the resin to contract and then expand when you turn the heater system on.

It is unlikely that a resin-repair windshield kit is going to make a 100% durable and permanent repair (except in the smallest of chips/cracks).

Therefore, if you are doing the repair as a cost-saving exercise e.g. you don’t have windshield cover in your insurance, I would strongly recommend you still start squirrelling away the money required to get there windshield replaced at some point in the future. Use the repair kit to “buy some time” as it were.

Conclusion – Do DIY Windshield Repair Kits Work?

In my personal experience (and this is a “one from one” kind of thing) they do work.

Although I was still able to see the crack, it was far less noticeable – to the point where you really had to look to see it – and furthermore the crack did not spread at all on a six hour drive home.

I still had the windshield professionally replaced with a brand new one, primarily because New Zealand rules dictate that a pro repair shop cannot fill/repair a crack that starts from the edge of the windshield – it must be replaced (rules in your local jurisdiction may vary, of course).

You can read my Rain-X repair kit review, as that was the product I used, for even more information and photos.

If you are going to try one of these kits, what really matters is being realistic about the outcome you expect from the repair. Don’t think you are going to wind up with a job that looks “as good as new”, especially if you are trying to repair a larger chip or crack. It may also be that the repair does not last particularly long.

However, considering how inexpensive these kits are, if your repair requirements are within the guidelines of what can be done, then I do recommend giving it a try.

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