19th July 2024

Simple Glass Cutting for glass painters.

Simple Glass Cutting for glass painters.
Simple Glass Cutting for glass painters.

In this video we show some simple glass cutting for glass painters. We cover the basics, enough for you to cut some simple square, rectangular and round sun catchers. We’ve kept tools used to a minimum as no-one wants to spend a fortune just to cut a few pieces of glass.

The glass used in the demonstration is 3mm float. A very common type of glass. I was lucky enough that someone was pulling down a greenhouse and gave me all the glass from it. It’s great to recycle/reuse the glass but, if do manage to get some glass like this, remember it is likely to have more flaws in it than new glass. This will lead to more breakages when cutting. (or that’s the excuse I’m sticking to at the moment).

Simple Glass Cutting for glass painters.


Simple Glass Cutting for glass painters.
Glass Cutting a straight line.

Simple Glass Cutting: Equipment:

As I said I have kept the equipment to a minimum. The only things I bought specifically for the glass cutting were the basic cutter and the circle cutter. The former was bought for a few pounds at a local DIY sore (B&Q) and the latter off Ebay (£5 – £15).  In addition to those you will need a ruler, a couple of surfaces to work on and a piece of small round wood (actually the material doesn’t matter much, a metal knitting needle or such like would be fine as well).

Cutting a Straight line.

To cut a straight line simple use the ruler to score it with the cutting tool. Then more it to the edge of a tale (or another straight edge) and simple snap it off. Make sure, when you are scoring the glass, that you hear the scratching noise. If you aren’t hearing that then you aren’t scoring the glass properly. Once scored you should see it clearly on the glass.

Glass Cutting a circle.
Glass Cutting a circle.

Cutting a circle.

Cutting the circle isn’t actually difficult, there are just more steps. As long as you follow the step carefully you should be OK.

  • Cut a piece of square glass at least 6 cm larger than the circle you want. (As you get better at this you can try reducing the amount of wastage).
  • Set your circle cutter to the size you want.
  • Place the circle cutter on the glass and before you fix it down ensure there is plenty of spare all round. It should be about 3cm either side.
  • Fix down your circle cutter.
  • Do one full circle with the glass cutter pressing down firmly. (Obviously you won’t be able to press down as hard on 2mm glass as you will on 3mm or 4mm glass). Again you should hear the scratching noise as you do it.
  • Turn the glass over.
  • Place your thumb on the score mark (or rather what is the reverse of the score mark) and press down until you see/hear the score open up. Continue moving around the circle pressing down with your thumb opening the score up. When you reach the full way round you should hear a slight click as the circle is fully opened.
  • You now have two separate pieces of glass, the circle and the outer.Unfortunately you still can’t get them apart!
  • Turn the glass back over.
  • Score 4 short lines, one on each side. They should start about 1/2 to 1 cm in from your circle and run to the edge (Honestly its much easier to watch this in the video!).
  • Now we nee to open each of these lines up. Put the small circular piece of wood (or whatever you are using) just under the edge of the glass so it is directly underneath one of the new score marks. It only need to be under the glass about 1/2 cm.
  • Press down on the glass either side of the wood. You a sort of bouncing movement adding pressure each time until the glass cracks (hopefully along the score mark). STOP as soon as you hear it crack. Don’t be tempted to press down any more.
  • As you go around doing each of the 4 scores you waste glass should fall away and you should be left with your circle.


If I’m going to lead up the edges of the glass then I just leave them as they are. If I’m not going to lead them up they I sand the down to get rid of any sharp bits.


Glass cutting isn’t difficult but it does take practice. Expect a lot of breakage when you are first starting out. ALWAYS be mindful that you a dealing with glass and glass can be sharp. Even the smallest slithers can make you bleed.  I recommend both gloves and eye protectors.

Finally, I used 3mm glass in this demonstration. 2mm is easier to cut but is also easier to break in the wrong place. 4mm would be good for clocks etc (once I’ve learnt to drill holes in glass) but is obviously harder to cut.

2 thoughts on “Simple Glass Cutting for glass painters.

    1. Unfortunately not (I like oval too!).

      Either you can do it freehand, having drawn your oval on the glass with a suitable felt tip e.g. one you can rub out after. Or, you can cut yourself out a template from some thick card or cuttable plastic. The trace round that. Obviously you would need a different template for each size you want. Once you have cut the shape then the breaking out is the same technique as with the circle.

      Hope that helps.

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