For the beginner I would suggest just practice cutting on inexpensive clear glass first. Learn to score your glass so that you get use to the amount of pressure you will need to put on your cutter to get the lovely ‘sound’ you hear when you know you are scoring the glass with the perfect pressure for a clean break.
Using your glass cutter, make your score, give a good tap with the back end of the cutting tool under the scored piece of glass. Tap several times up the entire length of your cut line. Generally this light tapping will let you visually see that the glass is ready to break where you cut it. Using a ‘pincher’ break the glass.
I have found that with certain glass, its breaks really easily, so once you get use to it, often just the tapping underneath will allow the glass to break on the cut.
When you are cutting small slivers or ‘taking bites’ off a piece of glass, tap underneath but then use your grozing pliers to break off the small pieces of cut glass.
I deal with textured glass differently. If it has an uneven surface on the front of the glass, I will glue my pattern piece to the backside of the glass (be sure you have your pattern piece glued on ‘the wrong way’ so that when you are finished cutting from the backside, you end up with your cut piece of glass having the interesting textured side on the front of your glasspiece.
Textured glass can be more uneven, thicker and more of a challenge to cut. It often is a bit more expensive than plain rolled glass as well. Because of this, I would say do a little practice cutting first. Cut a small piece of glass off your sheet of glass and just get use to the pressure and challenges that this textured glass will give you.
If you are a beginner, better to practice on a small piece off your sheet, than glue you pattern onto the glass, cut away and find that you are breaking your pattern pieces as you cut them.
When I was learning, and even now sometimes, if I am uncertain how a type of glass is going to react to cutting, I will always do a few little cuts to sample what it is going to be like to cut.
Often with very textured glass, and very small pattern pieces with curves in them, I will aire on the side of caution and rely on my grinder for the intricacies of the curves.
Cutting glass takes practice. Be patient with yourself and enjoy doing your stained glass piece.
