Mr. Glass

Cutting glass might seem intimidating, but this skill can be perfected rather quickly and easily, and can be very useful. Want to learn how?

Before you try this, beware – glass is not very tolerant of mistakes, and one false move could lead to a nasty injury. Even doing a perfect job would often leave little shards laying around, so don’t do this in your living room. Until you get used to it, better wear good work-gloves and cover your face with a mask or protective glasses.

To cut glass, all you need is a rotary glass cutter. These are often sold as kits, for around 5-10$ at any home depot or Lowe’s. A typical kit contains the cutter, a bottle of cutting oil, and sometimes some instructions as well. If you have such a cutter at home already, be sure not to let it get old. If it gets rusty or worn-out, it will not do its job well. Also, the cutting oil is much more important than you might realize. Another important tool is a metal ruler.

To cut the glass, place your ruler and tape it to the glass using some tape – the tape goes on the side of the ruler opposite where we intend to cut, of course! Dip the rotary cutter in the oil and shake-off any excess. Using the cutter, scratch the glass from end to end in a fast and uniform movement. Make sure you do it from end-to-end and not leaving even a few millimeters undone, as this could lead to the whole piece breaking unevenly. Note that the rotary blade is usually small, so you’ll have to find the right angle of holding it, so the ruler doesn’t keep it too high to touch the glass. Use just little pressure – the cut doesn’t have to be deep, and no matter what, don’t be tempted to do another round. If you missed it the 1st time, make another cut at least 1 inch to the left or right, or get a new sheet of glass. Doing the scratch correctly is the hardest part, and it may take a few practices until you get it right.

After the scratch, remove the ruler and turn over the glass. Tap on it gently along the scratch a few times using something hard. Usually, the other end of the glass cutter would be shaped like a ball, ideally for this. The tapping is not supposed to break the glass, but to give it tiny invisible cracks which will “prepare” it for the final break.

Place the glass over a table-edge, and hold it in place. Push gently the protruding side, while holding the glass well so it doesn’t fall to the floor after breaking. Just a small amount of pressure is all that is needed, and the glass should usually break cleanly and easily. Another way is to raise the glass and place a pencil under the scratch, and then push on the glass to make it break. Doing this for the first time is a lot of fun – it feels great to see how it breaks so easily and quickly.
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Lastly, use some fine sandpaper to smooth the glass edges. Be sure to use gloves at this stage, as the glass could cut the paper and go straight through your hand.
Congratulations! You are a glass cutter!