I decided to use some sort of release agent underneath the fibreglas when I do the windscreen fairing, so I can pop it off to finish it. This will make it a lot easier to get nice smooth edges. I'll bond it in place later. John Huft has a good description of what I plan to do.
I used electrical tape as a release agent when I did the canopy skirt, but I wasn't completely happy with it, as it leaves a bit of a greasy residue when you pull it off. Not a big deal on the fuselage where I used it before, but I hope to avoid that on the canopy. Several other builders reported good results with 3M 471 vinyl tape. Fibreglas doesn't stick to it, it doesn't leave much residue when you remove it, and it comes in widths up to 4 inches. I drove to all the major hardware stores in the Ottawa area, and no one seems to carry this stuff. I sent 3M an e-mail on Friday - hopefully they will give me a hint as to who might carry the stuff locally. There are a multitude of places I can order it on-line, if it comes to it.
Near Disaster - I was cleaning up the edges of the windscreen today on a portable table in the driveway. It was a beautiful day, sunny, with almost no wind, and I didn't want to have the plexiglas shavings in the garage. I turned to walk into the garage, when a freak gust of wind blew the windscreen off the table onto the driveway. I rushed over, and saw a big chip of plexiglas missing, with a small crack. Arrgh!!
Fortunately the damage occurred on the bottom edge, and it didn't extend too far in. The windscreen fairing will cover the damaged area.
I trimmed the edge to remove the part with the crack, and to smooth out where the chip shattered off. And, to cap it all off, I now have a long rub line where the plexiglas slid along the edge of the table as it blew off, and several small gouges where it landed on the pavement. I'll have to purchase a Micro Mesh plexiglas polishing kit, and invest a few hours of sweat.