If I cut Lexan on a bandsaw, what is the best way to sand out the cut marks
along the cut line? Sand paper? File? I want to make a new windshield and
the cut edge will be the top of the windshield (open cockpit).

You could start with a file if necessary and then go to abrasive paper.
Depending on how the file works start with say 200 grit paper and sand until
the texture of the lexan is uniform before moving on to a finer paper. Do this
till you have gone up to 1000 grit at least. Then get some crocus cloth and
use it wet. I was taught that at this point use one piece of crocus cloth and
use it up till it is gone. After that you can use toothpaste with pumice or
make a solution of chalk dust and turpentine with either apply with your finger
tips.

After the toothpaste the edges of the lexan should be as clear as the rest of
the surface. The important thing is to never move on to a finer grit until the
entire edge is uniform. We did this in A&P school and it will work. Don't
know of any mechanical techniques that will do as well.

John Dupre'