How to cut glass

Working time: 20

Total working time: 20

Skill level: Beginner

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Guide: BeginnerDIY ProjectsExplanationsHandy HintsStep-by-Step Instructions

Glass-cutting is always the section that concerns people. BUT the process is quite simple, this guide will give you an introduction to the different types of glass used in picture framing and provide a step by step guide to help you safely cut glass for your picture frames.

Before we get into the instructions, there is some information about choosing and working with glass, please read through this information if you are new to working with glass.

Selecting the right Glass for Picture Framing

Glazing Type	Description	Characteristics	Best Use	Required tool
Float glass	The industry standard and is ideal for everyday projects.	Rigid and brittle, making it easier to break.	Everyday projects	Toyo Glass cutter
Acrylic	Impact-resistant	Scratch-prone and prone to static build up when removing protective film.	Ideal for framed pieces that need to be shipped	Fletcher Score mate
Artglass	Specialist glass designed to minimize reflections and enhance clarity.	Minimizes reflections, enhances clarity and provides multiple levels of UV protection.	High-end and conservation framing	Toyo Glass cutter

For more details please read: How to choose the right glass

Safety Precautions When Cutting Glass and Acrylic

When cutting glazing materials like glass and acrylic, safety should always come first. These materials can break or snap unexpectedly, so taking the right precautions will help prevent injury.

Wear Eye Protection – When snapping glass or acrylic, small shards or fragments can break away. Safety glasses or goggles will protect your eyes from potential debris.
Use Gloves – Glass edges can be sharp, and acrylic can produce rough edges when cut. Wearing cut-resistant gloves will help protect your hands from accidental cuts while handling and snapping the material.

Taking these precautions ensures a safer experience when working with glass.
When starting out, practice with plain float glass to build confidence in cutting and handling. Use a ruler, a glass cutter, and the snapping technique on waste sections of glass to develop precision and control. Once you’re comfortable, you can progress to working with specialty glazing materials.

What you will need

Glass cutter
Ruler
Glass marker

Don't have some/all of the required equipment? Our shop can ship them right to your door.
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Instructions

⚠️ Safety First! ⚠️
When working with Glass always:

Wear gloves to protect your hands.
Wear eye protection to guard against glass shards when snapping.

Step 1: Position the Glass
Place a sheet of 2mm float glass over the back of the frame, aligning two sides and one corner with the inside edge of the frame’s rebate.
Helpful tip:
An alternative is to measure, then cut the glass to the “GLASS SIZE” size of the planned project – this is a better option when working with a larger piece.
Step 2: Mark Your Cut Line
Use a glass marker to make wide marks just inside the frame edge. For larger pieces, measure and cut to the exact glass size instead.
Step 3: Align the Rule for Scoring
Position the ruler 2mm inside your marks, ensuring the cutting wheel aligns with the center of the marks for an accurate score line.
Step 4: Position the Cutting Tool
Align the ruler’s edge about 2mm inside your marks to account for the width of the glass cutter head. Ensure the cutting wheel is centered on the mark.
Helpful tip:
Always start by cutting the shorter dimension before moving on to longer cuts.
Step 5: Score the Glass
Starting at the top, keep the cutter vertical and apply firm, even pressure as you make ONE clean score towards you.
🚨 Do not score the same line twice—if the first attempt is unsuccessful, turn the glass over and try again on the other side.
Step 6: Snapping the Glass
Snapping the glass requires a few specific actions to be done at once, but with a little practice, it becomes straightforward.
- Position for the Snap: Carefully slide the scored glass so the score line is directly over the edge of your work surface. Ensure a small portion of the glass (around 2-3mm) extends beyond the edge. This overhang is where the break will initiate.
- Support Below the Score: Place the fingers of both hands underneath the glass, aligning them precisely along the score line. Your fingers should be supporting the glass directly beneath where you want it to break. Keep your fingers relatively close to the edge of the work surface.
- Apply Breaking Pressure: Position your thumbs on the top surface of the glass, one on each side of the score line, close to the edge of the work surface. Now, apply a firm, even pressure by gently pushing upwards with your fingers from underneath and simultaneously outwards with your thumbs on top. This creates a bending force along the score line, causing the glass to snap cleanly.
- Encouraging a Clean Break (for longer cuts): If you have a longer score line, the break might need a little encouragement to run smoothly along the entire length. While maintaining the upward and outward pressure, gently wiggle the ends of the glass up and down (a small, controlled rocking motion, not outwards). This helps the crack propagate along the score.
Need help cutting glass? – Try our Glass cut to size service