Hi ive seen some cool things for visors theres this one way u can make a clay mould put it in the oven and a plexiglass sheet on top of it with nuts to weight it down THIS IS NOT RECEMENDED BECAUSE IT WILL KILL YOU AND YOUR FAMILY DUE TO POISIONG ETC BUT if u have another oven that not for food preporation then it'll be fine just make sure you use full saftey precaution such as google, respirator ( due to excess gases coming from plexiglass ) maybe and aprin made of leather and saftey gloves but the main one HAVE THE OVEN OUTSIDE NOT FOR FOOD PREPORATION AND HAVE FIR EXTINGUISHERS READY
and keep a good eye on it there is a topic on this and got alot of flak because he didnt mention proper saftey instruction so anyone could have already done it and has to potential of threating their lives but it worked out REALLY AWESOME!!! the only problem is it's clear not tinted so u'll have to find a solution to that but .
P.S the safest way would probibly be a vaccum forming table [SORRY IF I GET IN TROUBLE FROM MODS FOR MENTIONING THIS]