The primary point of entry for a car thief is through the car's window. Car windows provide security but are no match for a brick or hammer. Once the window is broken, the interior of the car is exposed to outside elements such as rain. A broken window also leaves the car open to vandalism. Replacement windows are expensive and often take a week or longer to replace because most auto glass dealers have to order them from the automobile's manufacturer. Using plastic and a few simple tools, you can make temporary replacement windows that will keep a car secure.
Make a template of the broken window. A good template is the key to creating a window that fits. Start by laying a piece of craft paper or construction paper over the window. Trace the window's shape, following the outside line of the gasket. The gasket is the rubber moulding that holds the window in place. If it's a window that has an identical mate on the other side, trace the unbroken window because the paper can be laid flat against the unbroken glass. Craft paper is more flexible than cardboard and easier to use when tracing a slightly curved window.
Cut out the template. Transfer the paper template to heavy cardboard, applying the template to the cardboard's surface with double-sided tape. Use a utility knife to cut out the template. Test fit the template to make sure it fits within the rubber gasket. Make adjustments if necessary. Measure the overall size of the template and purchase the replacement plastic. Polycarbonate is the best choice because it does not crack when cut with a jigsaw. Polycarbonate also has 250 times the impact resistance of glass, whereas acrylic has only 17 times. Use a 1/8-inch thickness for the replacement windows. Some windows use 3/16-inch material, which can be difficult to bend into place.
Mount the cardboard template on the sheet plastic using double-sided tape, which will hold the template in place while the sheet is being. Use a jigsaw to cut out the template. Follow the line exactly when cutting. If the piece needs minor adjusting, it can be sanded with a palm sander. Use 220-grit sandpaper to remove excess material. Once the template is cut, remove the plastic from the template. Leave the protective backing on both sides of the plastic in case further modifications are required.
Fit the template into the window's rubber gasket. The gasket has a U-shaped groove that the window sits in. If it's too tight, mark the tight areas and sand them down with the palm sander. Use 220-grit sandpaper to adjust the plastic where needed.
Remove the cut plastic from the window, then remove the protective backing from both sides of the plastic sheet. Apply a small bead of silicone caulking into the gasket's groove. Set the window in place and allow the silicone to dry to complete the project.
A properly fitting template is the key to success. Spending the extra time to perfect the template, saving time and money in the long run. Test fit the template until it fits correctly into the window.