How To: Cut Glass

By Scott Sidler October 23, 2017

how to cut glassSo you want to learn how to cut glass? Good! It’s an easy thing to do for any DIYer and it doesn’t require a lot of complex tools. In fact, learning how to cut glass in almost any shape or size should take no more than a couple minutes to learn. Curved shapes are just as easy as simple squares and rectangles.

Cutting glass is actually similar to cutting drywall in the sense that it is just a matter of scoring the materials properly and then breaking it along the score line. You don’t actually cut through the glass. Don’t worry, I’ll walk you though it in the steps below and in the video as well.

To get started you’ll need just one tool and there are three versions of the tool depending on how much glass you plan to cut.

  1. Steel Glass Cutter – These cutters are very affordable and often found at local hardware stores. Just like any steel tool they will dull over time and need replacement within just a couple weeks of moderate use. I would think of them as disposable due to their short life and low cost (usually $5-$9), but for a small, one time project, this is the perfect tool for you.
  2. Carbide Glass Cutter – These premium glass cutters are a bit more expensive ($25-$50), but they will last for years of heavy use without dulling. They cut cleaner and more consistently than the steel glass cutter and require less pressure as well. These also contain a small reservoir within the body for oil to lubricate the cutting wheel. If you’ll be cutting glass for multiple projects go with a carbide cutter.
  3. Mat Cutter – For production style square glass cutting, you also have the option of a wall mounted mat cutter. This glass cutter is expensive (several hundred dollars), and mounts on the wall, fits full sheets of glass, and can cut consistent square cuts super fast. These are usually the domain of professional picture framers or glass shops.

What Kind of Glass Can I Cut?

This technique works for most annealed glass 1/4″ thick or under. The thicker the glass the harder it is to cut so unless you have experience, cutting thicker than 1/4″ can be problematic without professional tools.

Also, if you try to cut tempered glass you’re in for a shock. Once cut, the entire sheet of tempered glass will shatter into a million pieces. Watch the video here!

You also cannot cut laminated glass or insulated glass units. Only singe paned glass can be cut like this.

How to Cut Glass

You’ve got your glass cutter ready and you’ve cleared some space on a flat, smooth work table so you’re ready to go. I prefer laying a moving blanket on the table to keep from scratching the glass as well.

One last tip before you get started: you can’t cut a piece of glass out of the center of the glass. You always have to be cutting from an edge. The video below clears this up in case that doesn’t quite make sense yet.

1. Mark Your Cut

Using a sharpie or wax pencil, measure the dimensions of your desired glass size on the glass. Using a straight edge, or T-square if you have one, connect the tick marks. If you are cutting a curve simply trace the shape you need onto one corner of the glass.

2. Score First Side

It doesn’t matter which side you choose first, but score only one side at a time with the cutter. Apply consistent pressure and only go over the glass with one clean pass. Multiple passes will wear out your cutter and cause the cut to be inconsistent.

You can leave the straight edge in place to use as a guide or freehand the cut. Both work fine and it’s just personal preference as to what is easiest for you to get a nice straight cut.

3. Snap the Score

Carefully slide the cut portion of the glass off the edge of the table and with a quick downward pressure, snap the piece off.

Repeat steps 1-3 for each cut you need to make until you are left with a piece of glass in the proper dimensions you wanted. Watch the video below to see the whole process in action.

Glass Cutting Hacks

If after cutting your glass you discover it is just barely too large for the opening you do have some options. If it’s too small, well, I’m sorry but there is no glass stretcher on the market yet so you’ll have to start over.

You can cut off rogue corners using the same glass cutter and even cut a slim line off one edge by scoring it as above and using a pair of running pliers to slowly nibble the excess away.

Another hack if you find you are long by a 1/16″ or so is to use a belt sander with 80-grit paper to ease the edge down just enough to make things fit.

There you have it, how to cut glass! Have fun, but be careful. Glass is sharp and can easily cut you back if you aren’t careful.

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6 thoughts on “How To: Cut Glass”

  1. A trick I learned years ago from a professional stained glass artist, was to dip the wheel of my glass cutter in a very light oil to keep the wheel from skipping. Something like kerosene, turpentine or paint thinner is perfect, but nothing heavy like linseed oil. And, never use a back and forth motion when scoring the glass…just that single pass. Excellent article.

  2. Can wavy glass be cut this way? We just found some to replace the broken panes in our windows but it will need to be cut to size.

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