This is not for the fainthearted. The canopy that fitted like a glove is no more - it split with a sickening sound that you would have to hear to fully understand. It was enough to put me off dinner the day it happened.
I was at the stage where everything was in place. There were just a few holes to drill where the flashing attaches. I must have pressed a little too hard while drilling (on the unsupported canopy) and that was it - a split radiating upwards from the drilled hole about 3'' and downwards to the edge of the canopy. As the canopy was lifted off the fuselage the split extended another foot or so - totally beyond salvage.
Since recovering from the trauma I have actually had some fun experimenting with various drilling techniques on the now defunct canopy. So here is what I've found:
Supporting the canopy with a block of wood at the drill site seems to help.
A 1/8' normal drill seems OK (at slow speed and light pressure). Anything over 3/16' shatters the acrylic as the drill penetrates the far side. A 1/4' drill actually shateters the acrylic in a spectacular fashion!
A step drill seems fine (after making a pilot hole). I tried fast and slow speeds, light and reasonable pressure with no apparent problems although the heat at higher speeds tends to melt the acrylic.
Even so, I will now purchase a specialized acrylic drill (as I should have done in the first place) to drill the pilot holes before enlarging with the step drill at slow speeds.
I would post a picture but feel it would cause too much anxiety to those who have not yet drilled their own canopy.
