How to Cut and Break Glass

GLASS CUTTING

How to cut and break glass may seem intimidating, but once you try it and get the hang of it, it’s quite simple! You really have to find the balance of strength and delicacy when working with glass. It’s stronger than you think, but handling roughly will lead to cuts on your hands and fingers.

Many types of steel and carbide glass cutters are on the market. There are cutters that oil the wheel as you score, others have special handles for those who have trouble getting enough scoring pressure. There is even a machine that looks like a small sewing machine that applies the correct scoring pressure for you. Finding the best method for you is all part of trying a new hobby, or perfecting one.FLETCHER-TERRY Gold Tip Glass CutterTOYO Pistol Grip - Glass Cutter - Self Oiling

Caution: Never try to draw the cutter over a score line twice; a new cutter can be ruined the first time.

 

Toyo Comfort Grip - Glass Cutter

Example of cutter being “pushed” for curvier or smaller cuts – “Pull” cutter for long straight strips

The traditional way to hold the glass cutter is between the first and second finger. The thumb supports the cutter on the underside allowing a free wrist motion as the cut is made. The cutter should be straight up and down or tipped slightly forward, the pressure coming from the shoulder, not from the wrist or fingers, as you draw the cutter toward you. This is the best way to cut long strips.

Glass Cutting and breaking instructions

To cut a small piece hold the cutter as for long cuts, apply pressure from the shoulder, but push the cutter. This allows you to see the wheel as you follow the mark on the glass. With the other hand hold the glass with your finger tips and use the thumb to help steady and guide the cutter as you push it to make the score.

Toyo Comfort Grip - Glass Cutter

Example of using thumb to “guide” cutter

Score lines must start at one edge of glass and end at another edge. You cannot start or finish a score line in the middle of a piece of glass.

The proper amount of pressure will make a small groove (the score line) When the break is made, the break will follow the score line.

Glass Score line example from GlassSupplies41

Scored glass example – This is what it should look like before you try breaking!

  • If too much pressure is applied, many small fractures will run in all directions other than the one extending down from the score line. If tiny slivers of glass fly from the score line, you are pressing too hard.
  • Never score over the same score line twice. You may permanently damage a good steel or carbide cutter.
  • Try to leave about 1/4″ between parts. This allows enough room to grip the glass with breaking pliers for a nice clean break.
  • Do not try to make corner cuts of less than 90 degrees. You can get curved cuts, but shallow ones. It is better to cut away glass in sections than try to make to sharp a corner cut.

    Cutting and scoring Glass examples

    This is a good example from Worden of where to score in order to get your PERFECT shape.

You are cutting glass AWAY to get your desired shape. That’s how you need to think. How can I REMOVE pieces of glass to get my shape? This example from Worden is good because it shows how many cuts it takes to get this partial circle shape. More cuts is always better for keeping the strength and integrity of your glass. Trying to make the above shape with only a few score lines would result in cracking your piece!

Here is a quick video on how to cut and break this shape:

Things to Note in the video:

  • none of my cuts are smaller than 90 degrees
  • Tapping the glass, as I did in the video, on top and below the score line carries the score THROUGH the glass. This makes the break easy! THIS IS KEY!
  • My use of tools – for straight and/or shallow curved breaks, I use the Running Pliers. For smaller more delicate cuts and curves, I use the Breaker/Grozier Pliers.
  • The amount of pressure I am using – I push with firm pressure! You should HEAR your glass scoring. Don’t push so that you shatter your glass though!

 

How to Break Glass

SAFTEY TIP! GLASS IS SHARP AND POINTY AND WILL DAMAGE YOUR EYES! WEAR SAFETY GLASSES!

Tap the glass above and below the score line to carry the score through the glass FIRST! Sometimes when you are tapping the glass your piece will just break out from the clean score, so make sure you are above the table when doing this.

Hand Method: This is usually only effective when breaking larger pieces with straight cuts. When breaking glass using your hands, grasp the glass on the edge that is closest to you, your thumbs on the top side of the glass on each side of the score line, with your index fingers on the underside of the glass. Holding the glass firmly, make a sharp upward and outward motion with both hands. The glass should snap cleanly and easily along the score.

how to Break scored glass with your hand at GlassSupplies41.com how to Break scored glass with your hand at GlassSupplies41.com

Straight score lines can also be broken on the edge of your work table. But this method should be used only for larger pieces. Position the score line so that it is parallel to , but slightly over the edge of your work table. With one hand firmly holding the glass on the table, with a downward movement, snap off the piece of the glass directly along the score with a downward movement.

How to break glass on the edge of the table from GlassSupplies41.com

Using the Running PliersThis is most effective when cutting shallow curves, straight cuts, and long cuts. Position the pliers with the screw side up and make sure the “center” line on the plier tip is in line with your score line.

Breaking Glass with a Running Pliers by GlassSupplies41

Using combo Breaker Grozier Pliers:  Position the jaws of the pliers parallel to, but not on the score line. If you look at the pliers clamped to the glass from the side, the curved part of the pliers will be up, as if it were smiling at you! A few millimeters from the score line. Breakers will separate the piece of glass from your score line. They are used to remove narrow strips and small pieces of glass, tile, china or ceramic!

Breaking glass with a breaker grozier pliers by glassSupplies41.com

How to Care and Store your Glass Cutter:

Keep your cutter in a jar with a layer of cotton balls or fabric on the bottom that is soaked in cutting oil. Keeping the cutter blade lubricated at all times is the BEST way to get a long lasting cutter head.

Any lightweight oil will work. Many artist use lamp oil because it is cheap, but BEWARE – the fumes and getting it on your skin is NOT HEALTHY. Many people get a headache when using it because of the fumes. We recommend Novacan Non-Toxic Cutting Oil. It’s still an easy price and for your health, it’s worth it.

CUTTING OIL for Glass Cutter by Novacan 8 ounce (237ml) bottle

CUTTING OIL for Glass Cutter by Novacan 8 ounce (237ml) bottle

I hope you enjoyed how to cut and break glass from GlassSupplies41! If you have any comments or questions, but sure to contact us! We love to help!

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