Learning how to cut glass sheets requires patience, practice, and the right tools. We'll show you how its done.
Time 20 to 30 minutes
ComplexityBeginner
Cost$0 - $20
Introduction
Learn how to cut glass safely and accurately with our easy-to-follow step-by-step guide. Perfect for DIY enthusiasts and experts alike.
Tools Required
- Circular glass cutter
- Dropper
- Glass cutter (pencil style)
- Marker
- Square or straightedge
Materials Required
- Cardboard
- Glass cutting oil
- Glass sheets
Cutting glass is a useful skill for repairing broken window glass, glass picture frames, mirrors, stained glass, and more. It allows you to create specific shapes and sizes of glass as needed. While some claim you can cut glass without proper tools, it’s not the safest method. You’ll need a glass cutter, typically shaped like a pencil, with a small wheel at one end for scoring the glass and a ball end handle at the other for snapping the scored glass free. This tool is great for making straight cuts, but for circular cuts, you’ll need a circular glass cutter. Glass cutter tools usually specify the recommended glass thickness for use.
I bought a glass cutting kit that included a circular glass cutter and a pencil-styled glass cutter. I used cardboard underneath the glass when making cuts, but an old rug or a carpet square would work just as well. Remember to keep children and pets away while working on this project, as small glass shards may fall unpredictably. Even if you don’t visibly see glass pieces when you are done, they are probably there. Run a vacuum over the work area, just in case. Also, wear safety glasses and gloves to protect yourself from any unexpected shards of glass.
Project step-by-step (11)
Step 1
Cutting Circles in Glass
Place cardboard on the work surface
To protect against glass scratches, position a piece of cardboard underneath the glass on your work surface prior to cutting.
Step 2
Oil glass cutting wheel
To lubricate the blade, use a dropper and apply glass cutting oil on the cutting wheel.
Step 3
Secure the cutter to the glass
Use the vacuum cup at the end of the glass cutter to secure the circle cutter to the glass.
Step 4
Adjust knife wheel distance
To adjust the size of a circle, move the wheel-cutting blade distance on the radius bar. For larger circles, increase the distance between the blade and the wheel, and for smaller circles, decrease the distance. Use a marker to mark the desired measurement on the glass for accurate measurements, and then tighten the blade.
Step 5
Score the glass
To score the glass properly, apply pressure to the blade head and move it in a single direction while maintaining steady pressure. It’s important to make only one scored circular line. Scoring more than once could result in an unclean cut.
Step 6
Free the glass
To free the glass, flip it over and ensure it is flat on the cardboard. Use the ball end of a pencil-style glass cutter to gently crack the glass by tapping it on the scored circle. You will notice cracks forming at the cut you just made, which will eventually cause the glass to break free completely. Do not tap on that spot further once you see a complete crack in the circle.
Step 7
Make relief cuts
If you’re having trouble freeing the glass and it’s not cracking properly, you can try making relief cuts. To do this, take a pencil-style cutter and make several score lines from the edge of the circle to the edge of the glass on the top side of the glass.
Step 8
Break the relief cuts
Flip the glass over and gently tap on the relief cuts that you just made using the ball end of the handle. The glass should break in that area once you see a full crack forming. Repeat this process until the glass circle is completely free.
Step 9
How To Cut Glass in a Straight Line
Score the glass
Just like when cutting a circle, place some cardboard on your work surface and always lubricate the cutting head of your tool before cutting the glass. Place a straight edge on the glass to act as a guide. Starting at one end of the glass sheet, begin scoring the glass with the pencil-style cutter until you reach the other end of the glass.
Step 10
Free the glass
Repeat the same process as the circular cut. If the edges are sharp and need smoothing, use a diamond-coated file, fine grit sandpaper, or a Dremel tool with a diamond wheel bit.
Step 11
FAQ
Where can I buy glass to cut?
Clear glass sheets can be purchased from most hardware stores, and colored glass sheets are available in craft and glass stores. Of course, glass is available online, but there are benefits to selecting the glass you want in person. Be mindful that glass comes in various thicknesses, so ensure the glass you purchase is suitable for your project.
Why do I need to oil my glass cutter?
To prolong the life of the glass cutter, it is important to apply glass cutting oil before use. The oil helps maintain a sharp cutter wheel for clean scoring. It is important to use oil specifically designed for glass-cutting tools.
How do I know when to replace the glass cutting head?
Glass cutting heads will not last forever. You’ll be able to tell if your glass cutting head needs to be replaced by the results of the scoring. While scoring, you will feel that the cut isn’t smooth anymore and requires a lot of pressure just to cut. There will probably be spots on the scored line that didn’t completely cut the glass. The life expectancy for glass cutter heads depends on how often they are used. If it’s frequently used, you’ll have to replace it sooner than someone who only uses it once in a while.
Originally Published: July 25, 2024
