Acrylic can be fickle. These guys are right. If you have a local plastics shop, it might be a good idea to do your local economy a solid.
That said, if you are feeling brave here is an excellent way to cut a fresh piece to size and shape:
Start with a new piece, masking still on both sides. mark your lines in pen so that they are easy to see. You'll need a band saw with a fine-toothed band at medium speed. Cut as close to your lines as possible, without actually taking the line. The band saw works because it is constantly cutting in the same direction. Next, using a sanding station, take your piece right down to the lines. You don't want to apply too much pressure because it will melt and distort the piece. You can also use the station to carefully champher the edges of your work. This takes a little practice. Once you have your precise size and shape, finish the edges with fine sand paper, sanding gently by hand, until the edge is smooth to the touch(160 grit works pretty well). Finally, peel back the mask 1/2" around all the edges, on both sides. Polish the edges with a cloth wheel on a bench grinder with a plastics polishing paste stick, until you have a glass-clear edge. Remove the mask and "Voila!"
If you need to drill your piece, do this before the final hand sanding. You will want to use a drill press with a standard bit (stay away, far away, from pilot-points). CLAMP YOUR WORK (this is why I have no feeling in my left thumb). With the press set at a medium speed, work slowly, letting the bit do the work. If you feel any resistance, you are drilling too hard and need to back the bit off the piece and let it cool for a few seconds. With care and patience, you'll have a perfect hole in one single piece of acrylic.
Lexan is a lot easier to work with, as far as cutting and drilling is concerned. But it can't touch the optical clarity and logevity of acrylic.
-Former (and sometimes active) Sign Fabricator.
If I think of it, I'll make a video. Could be next week, could be six months from now.
