Rodger,
I don't know where you have received your info, but it is a bit flawed.
First Lexan is a brand of Polycarbonate just as Plexiglass is a brand of
acrylic, but there is no comparison for strength. Polycarbonate is MUCH
stronger than acrylic. Yes, cast acylic is stronger and more optically pure
than extruded acrylic, but they both scratch easily unless the surface is
hardened. Polycarbonate is sold unhardened, hardened on one surface and
hardened on both surfaces. Eyeglasses and Harley windshields are made from
polycarbonate not acrylic. I also think large steps have been taken in the
recent past to make both products more UV resistant. I do not believe
yellowing is an issue anymore.
Steve

"Roger Long" wrote in message
...
I just called a plastic company to price half inch Lexan skylight
replacement. They said that, although Lexan is stronger, acrylic will last
longer in the sunlight and is more scratch resistant. They had no idea
what "longer" means.

If Lexan lasted 10 years instead of 20 I'd be happy. If it was 5 instead
of 10, I wouldn't.

Anyone here have an idea what the real numbers might be for clear
skylights on a sailboat in the Northeast? Any other pros or cons for one
plastic vs the other?


-- Roger Long