If I use an acrylic sheet for the screen it wouldn't bend the light as it should, it needs to be a solid lens. It would be like putting a tupperware bowl over the screen, just be a plastic window on the screen and wouldnt look like a CRT should. Now if you meat why didnt I use an acrylic sheet for a mold of the origional CRT then cast an epoxy lens from that... because I wanted to be able to cast multiple lenses, protoypes, back ups, etc. and didn't know how many I could cast using and acrylic mold vs silicon. Silicon I was able to make multiple. I may try the vacuum forming as molds later for different CRT sizes.