If you have a sliding glass door that closes off your patio or porch and you have accidentally broken the glass within the door, then you may be extremely frustrated about the situation. Luckily, you can replace the glass without completely replacing the entire door frame. This is often much cheaper. A piece of glass will be about $14 a square foot at the very most. This means that the glass will cost a total of $280 if the pane is five feet wide and four feet tall. The entire frame and glass piece will cost much more than this, so it is wise to keep frame damage to a minimum if you decide to do the glass replacement. The following tips can help you with this.

Release The Glazing

Before you begin your project, you should purchase and wear a pair of glass handling gloves. These gloves will prevent both cuts and punctures when handling broken and whole pieces of glass. The gloves are typically covered with a Kevlar composite material and feature grips made out of silicone or nitrite. 

Once you have these gloves, pick up and throw away any large pieces of glass that have broken away from the door. Afterwards, you should loosen the glazing compound that keeps the glass firmly in place within the frame. Loosening the glazing and pulling the pieces of glass out of the frame is less likely to produce damage than if you use a utility knife to cut the putty. 

There are several different methods you can use to loosen glazing, and heating the material is often ideal. Heating should be completed with a heat gun. Most sliding glass doors are surrounded by vinyl trim. Vinyl can sometimes become warped by heat, but the vinyl used in home applications is typically heat resistant vinyl. While this is true, you do not want to subject the sliding door frame to too much heat in case the material does burn. Make sure to keep the heat gun set at a low temperature between about 100 and 300 degrees Fahrenheit. Also, choose a gun with a flat nozzle so you can release heat directly along the edge of the window where the glazing sits. 

Pull Out The Glass

Many sliding glass doors will have mitered frames where the vinyl overlaps over the side edge of the glass pane. This helps to reduce leaking issues, and it creates a more aesthetic appearance. Unfortunately, the mitered edge can be snapped off if you pull on the glass too hard. To prevent this from happening, purchase a long, thin, and flexible putty knife. A one inch variety called a chisel putty knife will work well. 

As you heat up and loosen the glazing, slide the edge of the putty knife between the mitered edge and the window pane. Gently wiggle the knife back and forth to release the glass from the glazing and the vinyl frame. Work your way across the width of the glass, and gently pull it up and away from the frame once large broken sections become loose. If a portion of the glazing does not loosen and the glass becomes stuck, then use steam to try to loosen the glazing while you wiggle the putty knife.

If glazing is stubborn in one or two areas, then loosen as much of the window as you can. Place a piece of plywood up against the glass to brace it, and spread a generous amount of linseed oil on the glazing. The oil will soften the glazing and the window will pull out of the frame. Allow the oil to sit on the glazing for several hours before trying to loosen the glass. You can use this same linseed oil to soften the glazing across the door frame so it can be scraped off in preparation for the new glass pane.