Cutting glass is a skill that takes a bit of patience and practice. It entails scoring with the cutter and then running the cut across the score for an even cut. Using these instructions on a piece of scrap or waste glass several times will soon make you a pro. It is best to begin practice on thinner glass, perhaps 1/8” “double strength” glass. In the end the technique is virtually the same with most thicknesses with exception to the amount of pressure needed to “run” the cut. Once you learn glass cutting technique it will come as second nature in no time.
Remember: Do not attempt to cut glass that is tempered. This type of glass will shatter if you try cutting it. Laminated glass also requires a different technique than what is explained here. These instructions only apply to cutting flat, annealed glass.
How to Cut Glass
Place the glass on a clean, flat surface and thoroughly clean the area of the glass you intend to cut. It is highly recommended that the surface be firmly padded in some way, either with a towel, piece of low-pile carpet, or even cardboard if nothing else is available.
Slide your finger along the glass along where you plan to score the glass to ensure there are no items of debris to interrupt the path of the cutter. Anything in the way will ruin the cut as it will stop the cutting wheel much the way a shopping card wheel drags when it runs into the smallest of things on the floor.
Mark the line to be cut, endpoints and/or trace the freehand pattern or line with a marker. Clamping a straightedge… a ruler, yardstick or a square to the work surface to slide along is the best recommended way to hold your line.
Pick up the glass cutter and hold it in a similar way as a pencil. Apply a small drop of oil to the cutting wheel. You may then align the cutter in the direction you are cutting and look across your line to make sure you can properly reach each end of the cut.
Beginning at the edge of the glass from your starting point, apply the cutter to the surface with the handle pointing upward at least 45 degrees. Apply a similar amount of pressure as it would take to push a toilet handle and maintain it. Begin pushing the cutter along the desired line with a steady motion from beginning to end. You will hear a steady scratching noise as you score the glass.
Do not score the same area of the glass twice. This will ruin the blade of your knife cutter and could ruin the integrity of the cut.
Stopping the cutter, retracing and re-scoring cannot be done. Move the cutter with a steady motion with steady pressure, letting off slightly at the far end so that you don’t chip an oyster shaped chip off the end.
After scoring the glass, you may flip the glass over, and tap gently on the back side of the scored line with the ball at the end of the glass cutter. With some practice you may be proficient enough to skip the step of flipping the glass, but it will indeed make running the cut easier. Grab the glass with both hands and slowly pry the glass apart in a similar way you would separate two crackers at the perforation. Roll your wrists away from each other, applying pressure upward against the scored line. For more frequent cutting you may find it easier and faster to use running pliers to run the cut.
The cut should run from one end of the score to the other slowly separating the two pieces.
From there, you may take a fine grit sandpaper and dull the sharp edges. Wipe the glass clean and you’re finished.
