Posted for Mark Steitle <msteitle@mail.utexas.edu>:

Thanks to all who replied to my inital question as to how to trim the windows.  Before actually taking a cutter to my windows, I tried the various options on some scrap 1/4" plexiglass.  I thought that someone might benefit from my "research".

First, I tried using a router with a carbide cutter.  This made a nice effortless cut, but I was afraid of scratching the windows, or taking off too much too fast and ruining a window.  I was also aware of the difficulty of making a straight cut w/o using a guide.  With all the curved edges to trim, I decided this would probably not be my first choice.

I also tried using a die grinder, but I have had much difficulty keeping the cutter away from shiny surfaces.

I tried an abrasive disc in my Dremmel.  This worked pretty well.  A definite possibility.

I tried a bigger abrasive disc in my pneumatic rotary grinder.  Worked much better than the Dremmel, but left a messy edge.  Cuts through 1/4" plexiglass like butter.  A little scary.

Next, I tried using a Rotozip.  It seemed to be too slow and difficult to control (for me).  I guess I could have cleaned up the edges with a sanding block.  But definitely not my first choice.

Then I thought of another method.  I tried using the disc sander attachment on my Shopsmith, with a (new) medium grit sanding disc.  This worked great.  It took off the material in a very predictable manner and didn't damage any of the windows.  I covered the table top with a soft cloth to ensure that the windows didn't get scratched.  Worked like a champ!  I finished by finishing the edges by hand.

Thanks for everyone's input,

Mark Steitle
Lancair ES
Austin, TX