Thor, or should that be Zeus?

[AndrewMawson]

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 :(