Dealing with cracks and chips to your car windshield is crucial to ensure the safety of yourself and others travelling in your car. Cracks are often caused by rocks, pebbles and other debris on the road bouncing off the windshield. In most cases the damage is insignificant, but repair must be carried out as soon as possible to stop the crack weakening the entire structural system of the windshield, which can lead to more serious damage.
Leave the crack alone until you have the time and the necessary tools to attempt a repair. Modern car windows normally have a laminated plastic coating, which means that while parts of the windshield may shatter or suffer damage, underlying glass layers won't explode just because of a small crack or chip. There is enough strength in the windshield for it to stay intact long enough for you to take the car to a garage or auto repair shop.
Apply clear adhesive tape to the crack if it is more substantial; keep a roll in your glove compartment for quick and easy access. Use a wide roll so that any tiny, loose glass fragments are kept intact and to provide adequate preservation of the glass layers and laminate coating. Don't go overboard with the tape though, as you don't want it to restrict your view when driving.
Park your car on a level surface when you are ready to repair the crack.
Clean the windshield with soapy water, ensuring you remove all debris from the crack using the motorised rotary tool in your repair kit. You can use the tool to widen the crack slightly as this will make it easier to apply the resin.
Attach the repair stickers to the inside of the cracked windshield. Applied correctly, the sticker should cover as large a section of the cracked windshield as possible.
Inject the resin into the crack using the pump or syringe included in the repair kit. Avoid air bubbles by maintaining an even flow of resin. The resin must make contact with the inside surfaces of the windshield.
Attach the remaining stickers over the resin and leave it to cure for a minimum of four hours to give it time to set into the windshield. When you remove the stickers inspect the spot closely to make sure the resin has completely cured.
Take your car to a qualified professional if you don't feel confident getting rid of the crack yourself. In severe cases, if the windshield shatters, the entire glass pane will have to be replaced.