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

Roger Long wrote:
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

I always understood that Lexan was more likely to yellow after exposure
to UV. Acrylic was used in WW2 aircraft windshields and those
windshields are as clear today as when they were installed. But all
Lexan is not equal with respect to UV resistance. You might try a
different supplier who can provide better information.

It would be very surprising if a Lexan skylight did not last 10 years.

Chuck

----== Posted via Newsfeeds.Com - Unlimited-Unrestricted-Secure Usenet News==----
http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups
----= East and West-Coast Server Farms - Total Privacy via Encryption =----

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

Steve Lusardi wrote:
Rodger,
I don't know where you have received your info, but it is a bit
flawed.

I called the largest plastic supplier and fabricator in the phone book near
Portland, Maine. I'm always a bit suspicious though when I ask the girl who
answers the phone if I can talk to someone about something and she goes on
to answer the questions herself.

I take it you would go with Lexan?

Over 30 years of being involved with materials choices like this, I've often
found that "better", when applied to something like scratch resistance,
means you could detect a small difference in two alternatives used side by
side under identical circumstances but wouldn't be aware of any significant
difference otherwise. I'm trying to figure out if the scratch resistance of
these two materials falls into that catagory.

"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

One data point - Lexan is currently approved for huriccane shutters in
Florida. The manuafacuter provides a 10 year warranty against yellowing
(even under our hot subtropical sun.)