Lexan, buy the MR-10 its scratch resistant.

It is much less likely to break when something heavy (like you) wants to
break through it. I nolonger know the relative impact resistance of the two
materials but Lexan is much tougher and there is a reason bullet proof
"glass" is actually lexan. Under anything close to normal use a 1/4" peice
should never break at all, go thicker if the the hatch is really large.
Also when it does break it produces a blunt edge so it will not cut you if
you somehow do break through it. Plexiglass shatters sharp and though its
unlikley you will ever break it if you do you will get cut.

Good luck,

Tom
"Jude Douglas" wrote in message
...
I sure hope I don't get a war of words going, but I would like get some
recommendations on which sheet material to use for our sliding main
hatch: polyacrylate (Plexiglas, Lucite, Acrylite, Perspex, etc.) or
polycarbonate (Lexan). I know Lexan scratches easily but it is very
impact resistant (falling winch handles or a whipping snap shackle). I
know Plexiglas is a bit cheaper than Lexan but it is not a concern for
such a small size of project. To reduce temperature expansion stresses
and drilling difficulties, I plan to just use a flat sheet with a
squishy bedding (silicone?) and a sort-of loose oak frame with a
retaining bracket.
Can anyone offer some suggestions as to which is a better choice
material?

Jude and Randall