Tuesday, 30 September 2008
Cutting glass circles
I know there are a lot of people who have difficulties cutting glass circles so I thought I would just tell how I do it and hope it will be of help to somebody.
So, I start by cutting a square of glass a minimum of 2 cm larger than the diameter of the required circle, so for a 24 cm diameter circle I cut a square with sides of at least 26 cms. The smaller the circle the more excess is needed.
Using a circle cutter I then score my circle, trying to place it as near as possible in the middle of the square. Making sure to apply even pressure, I then score the whole circle only once. When I have scored the circle I then turn the glass over and place it on a softer surface, I use a fairly thick tea-towel folded in half.
I then apply gentle pressure to the glass above the score (this is easier with clear glass as you can actually see the score line). I do this with both thumbs, one pressing on the nail of the other and I use a really soft bouncing motion, gradually increasing pressure, until I see a crack appear in the glass. The crack should run in a circle along the scoreline. Once the glass begins to crack in this way I move my thumbs around the circle continuing to apply gentle pressure and watching the crack appear.
Once I can see a clean crack all the way around the circle I turn the glass back over and make a score from the circle to the outside edge of the glass where the circle is closest to the edge (ie at the centre of the side of the square). Repeat this score on the four sides. If the circle isn't almost falling out by itself, use your normal method to break along the score line starting with the part of the circle nearest the corners of the square.
After some practise it's possible to remove the circle by making only one further score which leaves the scrap glass fairly intact and ready for a picture frame or mirror (a lesson for another day maybe). Here's the scrap left after cutting the white circle seen above. The small dish is only there because my camera wouldn't focus without it.
Hope this is helpful!