I have been experimenting with 6 to 10 mil (0.006-0.010) thick mylar as a pattern. Since there is 0.02 clearance in the cutter wheel, I can get right next to the cutter wheel and get good support from the fairly ridgid maylar edge. I am using a thin point Sharpie to mark the pattern outlines on it. It is waterproof, marks easily and can be "erased" with alcohol. The mylar is easy to cut precisely. I have been attaching the mylar to the glass with a glue (UHU type) stick. So far I have been very pleased with the ease of using the mylar to guide my cutter. The glue from the stick seems to be waterproof, dries pretty fast and I think it will come off with alcohol or some other fairly mild solvent. Since the clock I am making (using my own 1/4 sawn white oak clock case copying the McNeil elongated octagon pattern) is my first really fairly difficult pattern, I just drew the pattern on an 11X 23 inch piece of paper and placed the mylar over the top and traced the lines with the Sharpie. I then cut the mylar pieces and placed them at the appropriate places on the glass.
I do have a question at this point. The glass is a translucent glass with a textured swirl in it. I am concerned that the swirl pattern may not have the best "flow" in the outcome of the pattern pieces. I find that I am "wasting" much of the glass in trying to match the swirl when cutting the pieces out. My approach has been to cut a section out of the purchased glass panel that will fit a number of pieces and put the patterns on the cut section of glass so that I can cut lines that will not be too complex to ensure that the glass will break along the line properly. It is hard to choose swirl patterns that will mate with the ajacent pieces without wasting a lot of glass. Can anyone comment on this and what their thoughts are regarding the importance of matching patterns?