Thor, or should that be Zeus?

[Chaz]

Poly-carbonate sheet is used in professional machines for chip control and operator safety. Used in Police riot shields. Don't use acrylic as it shatters. Even poly-carbonate will stress rack eventually if you make the fixings too tight - I need to replace the screens in my Beaver Partsmaster again having done it about four years ago - bolt holes should have had appreciable clearance for expansion and contraction, but I made them bang on :(

Thanks, suggested minimum thickness?

Just saw a good vid where the guy was using small alu extrusion (looked like 20 x 20) for the frame, might try that.