A glass cutter is an inexpensive tool which is easy to use. There are a few simple rules to learn.Most glass cutting and repair around the home is done with panes less than 1/8" or 3mm thick. Cutting this thickness is easy. But you must be careful with the sharp edges.
Before you do any cutting make sure you pay attention to the sharp edges of the glass you are working on. Glass is so sharp that you can cut yourself without even feeling the initial contact. Make sure you do your repair work safely.
Professionals wear leather aprons to protect themselves if they accidentally rub up against sharp glass edges. But even that is not enough with thick heavy panels. Shops use work tables with carpeted tops to protect the panels when cutting. The carpeted top also makes it easy to slide the pane around to make the next cut.
Cutting begins with a straightedge or a tee square to guide your cutter. The straightedge needs to be longer than the pie4ce you need to cut. At the starting point for the cut spray a little WD-40 or silicone lubricant on the glass to keep the cutter cutting wheel lubricated. Or dip the cutter in a little container of light oil.
Apply firm pressure on the pane, enough to hear the cutter scratching the surface of the workpiece. Slide the cutter along the straightedge in <b>one continuous stroke. Do not go back and try to re-cut, you will damage the cutter wheel. Practice cutting scap pieces in one stroke until you try your good piece.
After the cut has been made slide the pane so that the cut line is lined up with the sharp edge of your cutting table. If your pane is small, you can use a piece of plywood with a nice sharp edge as glass breaking edge.
Hold the pane flat against the table and grasp the scrap side of the glass which you want to remove and push down gently. The glass will break easily along the line you scored in it with the glass cutter.
If the scrap side is less than 4 inches wide you can grab it with pliers. Twist the pliers downward to crack the glass. After you cut, the edge will be extremely sharp. Take some 80 grit emery cloth wrapped around a piece of wood as a sanding block.
Angle the block at about 45 degrees to the sharp edge and sand down the sharp edges. Sand the 4 corners of the panel slightly too so they are not sharp. Only a little sanding is necessary to accomplish this. No need to press hard.
Sometimes with a long piece of glazing, you may not get a clean break line, you may have rough spots on the edge. You can sand these off with emery cloth too, although it may take a little longer to sand.
Glass shops use Emery cloth belts in their power belt sanders to quickly grind these areas down. Do your cutting slowly and carefully and make sure your work area is uncluttered so that you have room to work. You do not want to cut the pane and break it when you bump into something too close to your work table.