How To Repair Cracks and Chips in Your Windshield

Identify the damage

Types include:

• Chip: A simple divot without any radiating cracks.
• Bull’s eye: Essentially, a divot with a small crater around it.
• Spider: A divot or bull’s eye with small cracks radiating outward.
• Crack: A long thin split that may include a visible chip that started it.
  • In general, repairs for chips, bull’s eyes and spiders are the same, while cracks require a slightly different approach.
  • The damage I repaired was a spider chip, but the steps are similar to most other chips and crack repair kits. Modify as needed for your specific damage or kit.
  • The painter’s tape on the inside of the windshield is there for photographic clarity. You don’t need that tape on your own repair.

Dan Stout for Family Handyman

Clean out the damaged area

• Remove any debris in the crack to allow the repair resin to set up properly.
  • This is one reason manufacturers encourage making the repair as quickly as possible.

• Use the razor blade that came with the kit to pull any debris or loose glass out of the crack or chip.
• Wipe down the area around the damage immediately with a rag or paper towel.
  • A few inches on either side of the damage should be sufficient.

• Do NOT use a commercial glass cleaner. Any cleaner that gets into the crack can be trapped, making it more difficult for the resin to seal properly.
  • Although the kit didn’t call for it, I used a shop vacuum for extra help cleaning debris out of the chip.

Dan Stout for Family Handyman

Set up the base

The setup will vary depending on the type of damage and the specific repair kit. The RainX kit I used came with a suction cup base, perfect for repairing a chip.

• Center the base on the primary chip damage.
• Check the alignment from the inside and outside of the vehicle.

Dan Stout for Family Handyman

Dan Stout for Family Handyman

Install the resin chamber

• Screw the lower section (the resin chamber) of the included tube into place.
  • This creates a seal around the chip’s impact point, holding the resin that will be forced into the damaged area.
• Tighten far enough to push the rubber washer flat, but don’t go any farther than that.
  • Tightening too far can put pressure on the chip, causing misalignment or even spreading the damage.

Dan Stout for Family Handyman

Add the first drops of resin

• Verify you’re in a shady spot before adding the resin.
  • The resin cures with UV light. If you put in the initial dose while the sun beats down on it, it will begin to cure before it’s fully filled the damaged area.
• Add a few drops of resin to the resin chamber.
• Insert the top half of the included tube (the plunger) and tighten almost, but not quite, all the way.
  • This pressure, along with the tight seal you established in the last step, forces resin deep into the cracks.

Dan Stout for Family Handyman

Ensure good resin penetration

• Wait five to 10 minutes for the resin to seep into place.

Dan Stout for Family Handyman

• Examine the damaged area from outside and inside the vehicle.

Dan Stout for Family Handyman

• • The chip and crack should be much harder to see now.
  • If there are air bubbles, gently press against the windshield with your fingers.

Dan Stout for Family Handyman

• If cracks are still visible, unscrew the plunger, add a few more drops and re-tighten the plunger.
  • I had one crack that still didn’t get any resin, so I reseated the base to be centered on that specific crack, then repeated the previous steps.

Dan Stout for Family Handyman

Place curing strip and move to sunlit area

• Remove the whole base apparatus.
• Wipe away excess resin that dribbles down the windshield, but do NOT wipe resin off of the chip or crack itself.
• Place the plastic curing strips over the resin-filled crack.
  • The strips will self-adhere to the resin, so you don’t need to apply significant pressure.
• Pull the vehicle out into direct sunlight. Leave it there as long as the manufacturer recommends.

Dan Stout for Family Handyman

Remove the strip and excess resin

• Once the resin cures, remove the curing strip.
  • I pulled the car back into the shade to escape the heat, but you don’t need to at this point.
• Scrape the excess resin away with a razor blade.

Dan Stout for Family Handyman

• • Note the blade should be held at a right angle to the windshield. This is a little counterintuitive and does create a nails-on-a-chalkboard screeching sound, but this technique ensures you don’t accidentally cut too deeply into the newly formed resin.
• Examine the damaged area. If there’s a visible divot on the damaged area, top off with resin, apply a curing strip and move the car back into the sun to cure once more.

Dan Stout for Family Handyman

Repairing a crack instead of a chip

The process is similar for cracks. But instead of using the base applicator, you’ll apply the resin to the top of the crack and let gravity pull it into the center of the crack. You or a helper can gently apply pressure on either side of the crack from inside, helping it open up and suck in more resin.

Apply curing strips all along the resin-soaked crack, then cure and remove excess resin as described above.

Dan Stout for Family Handyman

Final product

In the end, I was extremely satisfied with the repair.

You can still see traces of the cracks if you’re in the passenger seat and look from the right angle. But from the exterior or the driver’s seat, it’s essentially invisible. (I think the elements still visible stem from waiting a decade to make the repair.)

Dan Stout for Family Handyman