How to Safely Break Glass after Using a Glass Cutter

Cut glass.
What You'll Need
Glass cutter
A metal ruler
Cutting oil
A whetstone (may be needed)

When you’ve used a glass cutter to score glass, you still have to finish the job by breaking the glass along the line you’ve made. One thing you must not do is use the glass cutter to go all the way through the glass. Instead, there are ways to break the glass properly that don’t use the glass cutter at all.

Step 1 - Score the Glass

Before you can break the glass, you have to score the glass along a line with your glass cutter. The score needs to be deep enough for the glass to break. Effectively, the glass cutter is used to weaken the glass along that line. Lubricate the glass cutter with cutting oil before you use it. Run it over the line in the glass three or four times. Use a metal ruler to ensure you score along a straight line.

Step 2 - Break the Glass

Having used the glass cutter, you now need to put it aside. There are three methods you can use to break the glass, and they all work well. Before you attempt any of them, however, wear gloves to protect your fingers from glass in the event of an accident.

Method 1

In the first method, hold the edges of the glass with your thumb on top and your fingers spread underneath. Have a firm grasp on the glass then rotate both hands outward at the same time. The glass will break along the scored line you’ve made.

Method 2

Another way to break the glass after using a glass cutter is even simpler, although you’ll need to practice it several times in order to properly master it. Put one finger under the line you’ve made with the glass cutter. Now use your other hand to lift the edge of the glass and give it a push horizontally. This gives a very clean break.

Method 3

The last method is the one most people use. Place the piece of glass on a table with the scored line made by the glass cutter along the table edge. Hold part of the glass firmly against the table. Grab the edge of the glass that extends beyond the table and push it down. The glass will break along the scored line.

Step 3 - Use Pliers

In most cases, you’ll achieve a completely clean break. There will be times, however, when you’ll find that the glass break isn’t clean and you need to remove some extra pieces of glass that extend beyond the line.

You’ll need to have a pair of pliers for the job. Place the jaws around the piece of glass you need to remove with the tips right up against the scored line made by the glass cutter. Grab the pliers firmly and pull down swiftly in one quick movement. This will take off the offending piece of glass.

Any sharp edges remaining along the cut edge of the glass can be smoothed down using a whetstone.