I have a square of 3mm thick polycarbonate (aka "Lexan" after a common brand, though mine is a different brand) that is roughly 50cm along each edge.
I need to trim a few mm off one corner and part of one side, as viewed from the front, in order to fit this polycarbonate into an aperture that is not quite square:
~5mm ↴ ↔ |------------\--| ↑ | \ | | \| | | 50cm | | | | |---------------| ↓ ← 50cm →
(Diagram not to scale.)
I tried using a small surform, but although my surform is sharp enough to work well on wood, it makes very slow progress in this polycarbonate sheet. Coarse sandpaper also makes very slow progress.
I am thinking of using a tenon saw to cut off the corner concerned, but I am concerned about cracking or otherwise irreparably damaging the sheet.
Bench tools aren't an option, unfortunately, both because they aren't available on-site, and because there wouldn't be room to deploy them even if they were available.
Question: does the tenon saw sound like a good bet, or is there a better tool to use? Either way, should I do any specific prep, such as applying masking tape where I will be cutting, to reduce splintering?