1/8 Plexi???

[MetalMan]

If it's plexiglass, don't use it. That stuff isn't very flexible and will crack very easily.

You can use polycarbonate (often mistaken for plexiglass). It's clear, and in the Lexan form (GE's polycarbonate is called Lexan) is bulletproof at the proper thickness. It's very flexible, and can take harsh impacts.

That said, if you do use polycarbonate, you're gonna want to use 1/4" thick, as the 1/8" thick stuff will be too flexible.