When building French style windows, we need to cut many diamond shaped pieces and it would be tedious to draw around a pattern piece for each one. So we came up with a system for cutting them quickly. When we cut vecchio glass the challenge is even greater because of the roughness of the glass. If you follow these steps when trying to cut glass into diamonds, you will find your speed of cutting out the window will be much faster and you'll be able to cut the rough glass successfully.
As you can see in this photo, the glass has a lot of texture. It has a rough side, which I turn down for the cutting, but the smooth side has seeds and bubbles in it, so it's tough to get a clean cut.
Take one diamond pattern piece and lay it out on the sheet of glass so you can get the glass oriented. you'll want all the pieces to run with the texture going up and down the height of the diamond, so turn the entire sheet of glass so that the straight line you'll be cutting lines up with the pattern piece.
In this photo, I've already cut a few strips and I'm cutting one which runs the length of the sheet of glass. I dip the cutter in oil and run the wheel up and down the glass lightly to spread some of the oil on the surface that I'm going to score.
You'll have to hold the glass from slipping with your left hand as you score using the glass cutter using your right hand. Exert more pressure than you do when cutting smooth glass and try to plow through the spots where the cutter hits a seedy spot and wants to stop.
Then, grab the glass with both hands and rock them apart to break the entire strip free from the sheet of glass.
Then, slide the sheet against the strip cutter guide edge on the table to set up for the next strip.
Once again, I'm able to use my hands to rock the two pieces apart. Many times I use running pliers when breaking strips of glass, but these are wide and the glass is uncooperative.
This edge cut off leaving a piece that sticks out and I have to score and break off a bit of the corner before I can line the edge of the glass up against the strip cutter guide.
When you're done, you will have a whole stack of strips.
Take the strips, one at a time and cut out diamonds. Take the pattern piece you started out with and line up the glass strip so that you are cutting the glass at the proper angle and then draw a line on the workbench using a sharpie marker so you can line up future strips with ease.
After scoring the diamond, use the edge of the strip guide as a raised straight edge to snap the glass off.
And lay out the finished diamonds on your French design window pattern. You will find that often the edges will be smooth enough that they will not require grinding, but make sure to grind those that have imperfections so that they will not be weak and subject to heat cracking.
Source by David Gomm