Casting your own tail light lens

Does anyone here have any experience making a tail light lens??

I am working with a 63 valiant wagon and the tail lights are nearly impossible to find, so my idea is to make a pair.

I have one NOS lens and I am pretty sure on 63 they are the same from side to side??

Does anyone have any idea where to get the materials to make a lens??

I really don't want to use the NOS lens but I would rather make a pair so that they are replaceable because if they ever get faded or busted, then I can just re-cast another pair.