[IKE]

Yeah the plexi(acrylic) vs. lexan(polycarb) mistake is a bad one.

We had some high stress pieces of 3/16 lexan on or robot this year that began to break after the first regional. We replaced them with 3/8" ??? Clear stuff. They snapped in the first match at the second regional. Turns out they were plexi.

The solution ended being going back to the thinner lexan and paying closer attention to surface cracks. A bandsaw will leave gouges perpendicular to the material thickness where-as a dremel sanding drum will make the gouges parallel to the thickness and thus slightly tougher.

Noticing that this looks like a non-structural body panel, here is a little secret:
McMaster Carr sells polycarbonate film (0.02-0.04"). Attached with velcor, this makes very puncture resistant "armor" without adding much weight. Be careful if you cut sharp inside corners into it as this can initiate a tear quite easily. Also, going much less that 0.020" is pretty thin stuff and thus not terribly strong.