what do you use when replacement curved glass isn't available? poly carbonate scratches just by looking at it. aircraft use plexiglass but has anyone used it in their car with good results. we need a substitute rear window for our '49 plymouth fastback.
Polycarbonate ("lexan") is actually tougher and more scratch resistant than plexi but has much poorer UV resistance so shorter lifespan in sunlight. Unfortunately there is no good substitute for glass.
They make it hardened and polished for the sign industry. It seems to hold up well enough. I guess the upside is that you can cut it easily so when it goes bad its easy to replace. You are correct though, there is really no replacement for glass.
Back glass usually easy to find compared to windshields because they get less wear. There must be a used one around if you look for it. You might try advertising on the AACA forums or P15-D24 forums.
I would think finding a good used one would be what I would try first considering there really is no good substitute at least long term.
Again, no location as to where he is. If you want help, you should make it easier for us to help you. If you are near Harrisburg, Pa. contact < chevsotolac > here on the H.A.M.B. Stan gets into a lot of old junkyards, and can usually tell you what is available.
A used '49 Plymouth fastback rear window glass should be very find-able. Shipping might be a lot, but even if you have to pay up for one, it's a much better solution than a plastic replacement.
Try Pilkington Ohio, now a subsidiary of NSG group. I was able to get reproduction curved glass for old mopars at reasonable prices. Jack E/NJ 811 Madison Avenue Toledo OH 43604-5684 USA +1 800 221 0444
Is this the body style? Here's the thread I got the picture from. https://www.jalopyjournal.com/forum/threads/1949-p17-plymouth-coupe-fastback.1031491/
I suspect that plymouth & dodge fastbacks shared the same glass. Possiblly some desoto & chrysler sedans as well in this immediate post WW2 era. Jack E/NJ