For replacing the glass, it has to be figured first how it will be taken out. Even though it is shattered into countless pieces, the glass would have to be removed from the edges before installing a new one. For a door glass, the door panel has to be removed to access the mechanism that moves the window up and down. The glass is attached below. The windshield chip repair and rear window glass requires the trim and the rubber gasket to be removed. The rubber gasket has to be replaced with a new one as the new one is installed. The car manual will be of help for removing and replacing the glass.
Those who want to save time and money may choose to repair small blemishes on their own using a repair kit. These can be purchased at any auto parts store or ordered online. In the kit you will find the epoxy resin and the tools to apply this. Care needs to be taken when using these, and the outdoor conditions must be warm and dry. After the repair is done the windshield will need to be able to cure in the sunlight for a few hours before maximum strength is achieved.
If the chip is smaller than a quarter and the crack is less than 12 inches long, they would most likely provide service to you at the convenience of your home. The repair kit they will be bringing will contain several materials, tools and equipment. This would include a windshield repair bridge that is self-leveling and is able to reach anywhere on the windshield together with the injector. A crack expander that slides easily and reaches low on the windshield. An A.C. powered ultraviolet curing lamp and a 15 watt, 22 inches bulb for curing long cracks. A drill if the chip needs to be cleaned. A curing film that enhances the ultraviolet rays for faster and complete curing, a UV protected syringes designed to protect the resin from the sun's ultra violet rays, the resin and some other stuff.
It will save you money in a way that instead of hiring someone to repair your windshield, you will be able to do it yourself. Or, changing your windshield will cost you more money because you will pay for installation and repairman. It's a great feeling that you could tell the world that "I can fix auto glass repair my own windshield". The question will be does it really work?
If a rock hits your windshield while you are driving when it is already cracked, this can cause it to shatter too and you will not be able to see the road. Dings and scratches generally won't do this but there is always that risk factor that you have to be cautious about.
Windshield cracks and blemishes can be troublesome. You can never really guess what is going to happen; they almost always start small and end up spider webbing across the remaining windshield. Some rock blemishes only leave chunk of glass missing. If not treated correctly it can turn into a large crack as well.
Be sure to choose a licensed glass shop in your area. There are a lot fly by night shops out there. You pay a lot of money for your vehicles so you want quality work at a fair price. Do the homework before you have this procedure done because proper preparation before installing a windshield will keep your car from having rust issues which may cause water leaks.