for racing aplications lexan is "the" material to use! plexiglass upon
impact or being impactes itself tends to break into long and rather pointed
shards. the resulting injuries from plexiglass windows and windscreens are
usually rather nasty puncture wounds. lexan tends to pop out of frames or
rubber gaskets intact with little to no breakage. lexan also has no memory
where as plexiglass does. i have a curved windscreen on my H-modified
sports racer made of lexan and a moulded plexiglass one too. the moulded
plexiglass one wich was shaped with a heat gun will retain that shape for
near eternity. the lexan windscreen springs back to a completly flat sheet
of material even after being in place for 5 years. and i must say the
windscreen is a full width cockpit witth wrap around ends. i choose
lexan. and i recall where in some sanctioning body's rules reading where
lexan is highly reccomended as the replacement for all glazing.
chuck.
----- Original Message -----
From "David N Waldmann" <david at vermonthardwoods.com>
Subject: Re: broken racing widnshield
> I would say that for Lexan to break the way you described it is extremely
> unusual. However, Lexan is susceptible to stress fractures when aromatic
> solvents have been applied to it (Benzene, Naptha & Toluene are the
> principle ones). If you (or the uninformed installer) had used a solvent
> containing one of those to clean the windshield and being that the
> windshield is either under tension in installation (the slightly curved
> stock shape) and/or under continual flexing during driving, it is possible
> that a stress crack could have been formed.
>
> You might also find that for a windshield a higher strength Lexan is more
> applicable, there are a dozen or more variations.
>
> In spite of an isolated incident, Lexan is Not VERY breakable. Take a
scrap
> and have at it with hammer if you don't believe me.
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