How To Cut Glass
Learn how to cut glass. Cutting glass is a delicate business whether you are working on stained glass or simply cutting a new window pane.
Cutting glass is a delicate business. Whether you are working on stained glass for ornamental purposes or simply cutting a new windowpane, using the correct tools and procedures can save you a tremendous amount of frustration.
During the Middle Ages, stained glass windows were made by fitting pieces of colored glass into lead channels or frames. This method is still used today for making larger windows. Stained glass is found in some of the world's most beautiful windows, murals, and lampshades. This type of glass comes in a wide variety of textures and colors, including translucent and opaque. Although antique glass is hand made, most glass is colored by adding metal alloys such as iron, cobalt and copper. Most modern glass has the same beginning as ancient glass. It is made up of molten silica sand. To create the polished surface on glass it is floated on a bath of molten tin. It is then heated and cooled. Anytime you are working with glass it is wise to wear a good pair of heavy-duty gloves and to protect your eyes with goggles. You will also need a flat solid surface to work on and in cases where you are cutting straight cuts a ruler or straight edge to follow that will insure your cuts are even.
If your project is working with stained glass to make an ornament or lampshade there is a much simpler process you can use called the copper foil technique. When working with even simple pieces such as these you will need to solder the pieces together. To cut stained glass you will need to begin by drawing out a full size design of your choice. Make a carbon copy of the design on light cardboard. Cut the carbon copy of the pattern into the glass. These will be your templates for the individual pieces of glass. Using the pattern as your guide trace around it with a grease pencil. Dip the wheel of your glasscutter in a light machine oil or kerosene. Take the cutter in your hand and hold it between your index and middle finger. Brace it with your thumb. Score just inside the pattern line with your glasscutter. With gloved hands and using grozing pliers, break the glass with your hands pointed in the direction of the curve. If the glass doesn't snap immediately, tap the score gently on the back with the ball end of the cutter and try again. Sharp curves should be cut in stages. Remove as much excess glass as possible with straight or gentle curve cuts. Then make the final curve. You can remove any rough edges of the glass you are cutting with needle nose pliers. As you cut each piece of glass, lay it on the cardboard pattern you have drawn. This will save confusion when you are ready to begin putting the piece together. Once all your pieces of stained glass are cut you are ready to wrap the edges of each piece with copper foil and replace it on the pattern. You can purchase rolls of paper backed copper foil and sheets of stained glass at any available stained glass specialty shop or most craft stores. Now you are ready to put your pieces of stained glass together.
If you are making a straight cut in a piece of glass for a window pane or table top you will need to begin by holding the straight edge along the line to be cut. As with the stained glass, dip your cutter into a light machine oil or kerosene. Take the cutter between your index and middle fingers bracing it with your thumb. It is better to cut straight glass while standing so you can lean over the glass. This gives you much more freedom of movement. At the far edge of the glass press the cutter down and move it toward you along the straight edge or ruler. Apply a firm, even pressure as you move the cutter. The sound that a glasscutter makes when cutting the glass is somewhat like radio static. Cut in one continuous motion straight to the end and allow the cutter to come completely off the glass.
To break the glass you will need to put on gloves. Pick up the glass and hold it facing away from you. Hold the glass between your thumb and fore fingers on each side of the area you have scored. Gently apply an even pressure pushing the glass down and outward with your thumbs while pressing outward with your fingers. Continue to steadily apply pressure until the glass snaps in two pieces. Use grozing pliers or needle nose pliers to clean up the rough edges. If you are trying to snap off a narrow piece of glass you should grasp it with grozing pliers to make the break.
When cutting circles in glass place the pane on corrugated cardboard. Using a circle cutter, position it on the glass with the suction cup in the center. Score a circle by rotating the cutter arm around the cup with even pressure. Turn the pane over and press gently along the score with your thumbs not quite breaking it out. Turn the pane back over and remove the cardboard. Then score free hand lines from the corners of the glass to the original score. Use your pliers to break away the pieces around the circle and use your needle nose pliers to clean up any rough spots. Since the thickness and types of glass vary you will need to ask a retailer which glass is best for your application. Be sure to always store and carry glass panels upright so they will not break under their own weight. Before you begin any glass cutting project be sure the glass has been wiped clean with a commercial cleaner.