What you can actually fix at home
A windshield chip smaller than a quarter, with damage that hasn't spread into a spider web pattern, can often be repaired with a DIY kit from an auto parts store. The repair won't make the chip invisible — you'll still see it if you know where to look — but it stops the crack from spreading and restores enough structural strength that the windshield won't fail during temperature changes or bumps.
Chips larger than a quarter, cracks longer than a few inches, or damage in your direct line of sight are better left to a professional. A bad repair can actually weaken the glass more than the original damage, and if the windshield fails while you're driving, you lose the structural support the windshield provides in a crash.
The repair works by filling the chip with a clear resin that hardens and bonds to the glass. The resin won't restore the glass to its original strength, but it seals out moisture and prevents the chip from becoming a long crack.
Key Takeaways
- DIY windshield repair kits work best on chips smaller than a quarter that haven't spread into cracks.
- The repair involves cleaning the chip, injecting resin, and letting it cure for the time specified in your kit — usually 24 hours.
- Chips in your direct line of sight, large cracks, or damage near the edge of the windshield should be repaired by a professional.
- A successful DIY repair stops the chip from spreading but won't make it completely invisible.
What you need to buy
A windshield repair kit costs between $10 and $30 and contains everything you need: a bottle of resin, an applicator tool or syringe, a curing strip or cap, and sometimes a small cleaning tool. Brands like Permatex, 3M, and Rainx all make versions that work similarly. You don't need to buy a specific brand — the basic chemistry is the same across them.
Read the kit instructions before you start, because the exact steps vary slightly. Some kits use a syringe to inject resin; others use a brush applicator. Some require you to explore a curing strip to the outside of the windshield; others have you cap the repair from inside. The kit will tell you how long the resin needs to cure — usually 24 hours — and whether you can drive the car during that time.
You'll also need a clean cloth, rubbing alcohol, and a way to keep the repair area dry while it cures. If it's raining or about to rain, wait for dry weather or cover the windshield with a tarp.
The step-by-step repair process
Step 1: Clean the chip. Use rubbing alcohol and a clean cloth to wipe away dirt, dust, and any loose glass fragments from inside the chip. Let it dry completely. If there's debris stuck in the chip, use the small cleaning tool that came in the kit or a toothpick to gently remove it. Don't scrape aggressively — you're just clearing out loose material.
Step 2: Prepare the resin. Follow the kit instructions exactly. Some resins come ready to use; others require you to mix two components. If mixing is required, do it in the order and proportions the kit specifies. Work quickly once the resin is mixed, because it begins to harden.
Step 3: explore the resin. Use the applicator tool or syringe to fill the chip with resin. Push it down into the chip so it reaches the bottom and fills any air pockets. You want the resin to overflow slightly above the surface of the glass. Don't worry about the excess — you'll remove it later.
Step 4: explore the curing strip or cap. If your kit includes a curing strip, press it firmly over the repair on the outside of the windshield. If it includes a cap, screw or press it onto the applicator tool from the inside. The curing strip or cap keeps air and moisture out while the resin hardens and also helps the resin cure evenly.
Step 5: Let it cure. Leave the repair untouched for the full time the kit specifies — usually 24 hours. Don't drive the car, don't wash the windshield, and don't touch the repair. Temperature matters: the resin cures faster in warm weather and slower in cold. If it's below 50 degrees Fahrenheit, the repair may take longer or not cure properly.
Step 6: Remove excess resin. Once the resin has fully hardened, remove the curing strip or cap. Use a plastic scraper or old credit card to gently scrape away the excess resin that's above the surface of the glass. Scrape at a shallow angle so you don't scratch the windshield. Wipe the area clean with a damp cloth.
When a DIY repair won't work
If the chip is in the driver's direct line of sight — the area you look through without moving your eyes — a professional repair is safer. Even a clear repair can create a slight distortion, and that distortion in your line of sight can affect your vision and reaction time.
Chips near the edge of the windshield or along the frame are also risky to repair yourself. The glass is thinner and more flexible at the edges, and a DIY repair may not hold. Cracks longer than a few inches, or chips that have already started to spread into a web pattern, are beyond what a DIY kit can handle.
If the chip has exposed the inner layer of the windshield (laminated windshields have a plastic layer sandwiched between two panes of glass), the damage is structural and requires professional replacement, not repair.
What to expect from the finished repair
A successful DIY repair will stop the chip from spreading and restore the windshield's ability to handle temperature changes and minor impacts. You'll still see the repair if you look closely — the resin fills the chip but doesn't restore the glass to its original clarity. In bright sunlight or at certain angles, the repair may be more visible than others.
The repair is permanent once it's cured, but it's not as strong as the original glass. If the chip is hit again or if the windshield experiences a major impact, the repair may fail and the crack may spread. This is why chips in critical areas should be handled by a professional — the stakes are higher.
If the repair fails or the chip spreads despite the repair, you'll need to have the windshield replaced. Most insurance policies cover windshield replacement with a low or zero deductible, so check your policy before paying out of pocket.
Preventing chips from spreading while you wait
If you can't repair the chip right away, keep the windshield as stable as possible. Avoid sudden temperature changes — don't blast the defroster on high on a cold morning, and don't park in direct sun if it's very hot. These temperature swings can cause the glass to expand and contract, which makes small chips spread into cracks.
Drive smoothly and avoid potholes and rough roads. Bumps and vibrations can also cause a chip to spread. If you're worried about the chip getting worse, cover it with clear tape on the outside to keep moisture out, though tape is only a temporary measure.
Frequently Asked Questions
Can I repair a chip if it's raining or humid outside?
No. Moisture prevents the resin from curing properly and can trap air bubbles in the repair. Wait for dry weather and make sure the chip is completely dry before you start. If rain is forecast within 24 hours of your repair, wait until the weather clears.
How long does a DIY windshield repair last?
A successful repair can last for years, but it depends on how much stress the windshield experiences. If you drive mostly on smooth roads and avoid extreme temperature changes, the repair may last as long as you own the car. Heavy use, rough roads, or another impact to the same area can cause the repair to fail sooner.
Will the repair pass a vehicle inspection?
That depends on your state's inspection rules and the size and location of the chip. A small chip that's been repaired and is outside your line of sight usually passes. A chip in your direct line of sight or a repair that's visibly failed will not. Check your state's vehicle inspection standards before you repair.
What if the resin doesn't harden after 24 hours?
Cold weather is the most common cause. If the temperature was below 50 degrees Fahrenheit, the resin may need more time. Move the car to a warmer location if possible and wait another 12 to 24 hours. If it still hasn't hardened, the kit may be defective — contact the manufacturer or try a new kit.
Can I drive the car while the resin is curing?
Most kits say not to drive during the curing period, though some allow light driving after a few hours. Follow your kit's instructions exactly. Driving creates vibrations that can disturb the resin before it's fully hardened and can introduce air bubbles into the repair.