Acylic or Polycarbonate???

[grp.boat]

I am renewing my plastic windows and want to put a wiper kit on the new setup. is there an acrylic or polycarbonate that will not mark when using a wiper kit. the windows have a bend in them so i cant use glass...

[gonzo]

Acrylic (plexiglass) is harder and can be polished. Polycarboante (lexan) is more shatter resistant but too soft to be polished. I think acrylic is better. You can sand it to 1500 grit and then polish at low speed.

[marshmat]

I seem to recall having problems with polycarbonates being easily scratched; acrylics are harder and won't scratch as easily, but they don't take too well to impact of any sort. If it's liable to get things dropped on it, lexan (polycarbonate) wins out, but for windshields the acrylics will probably last longer before they're too scratched up to see through. Neither's as good as glass though.

[RHough]

Plexiglass is the choice. There is a rating for use in automotive glazing, I can't remember the spec number offhand, but one brand name that I know meets DOT spec is Acrylite Plus. It is engineered for high impact resistance and high abrasion resistance.

[grp.boat]

thanks for the response.

steve

[D'ARTOIS]

Plexiglass = polycarbonate be it the commercial name of Dupont whilst Lexan is the name that GE plasitcs gave to their polycarbonate sheets.

[RHough]

Plexiglass = polycarbonate be it the commercial name of Dupont whilst Lexan is the name that GE plasitcs gave to their polycarbonate sheets.

If thinking that makes you happy, I won't argue ... :p

Plexiglass = polyacrylate

Lexan = polycarbonate

>> Question - What is Plexiglass? Is it the same as
>> polycarbonate? and what are its electrical properties?

Plexiglas is the same chemically as Lucite: poly(methyl methacrylate).
Polycarbonate is Lexan. The elecrtical properties of Plexiglas are pretty
boring: it is an insulator.


Richard Barrans Jr., Ph.D.
Chemical Separations Group
Chemistry Division CHM/200
Argonne National Laboratory
9700 South Cass Avenue
Argonne, IL 60439

[D'ARTOIS]

Thank you, I don't mind at all to be corrected if I am wrong: on the contrary!!

I was told by an plastics engineer that Plexiglass was Dupont's and Lexan GE's
for polycarbonate.

[RHough]

Thank you, I don't mind at all to be corrected if I am wrong: on the contrary!!

I was told by an plastics engineer that Plexiglass was Dupont's and Lexan GE's
for polycarbonate.

That's why I put the :P in there.

Please return the favour when I get things wrong!

I learned about the properties of the two in the process of designing windshields for motorcycles.

[yipster]

somewhere on this great site (http://www.taylormarine.com/windshields/index.html) i was just reading some definitions an hour ago..

[artisan]

ok, well lexan is a from of polycarb which has a protective cover on it. This is designed to stop it from scratching as easily as normal polycarb. It is very expensive and once scratched is rendered useless.

Polycarb is almost indestructable but easily scratched. Acrylic will not scratch as easily as polycarb but you loose the tough properties, how ever you can get a cross between Acrylic and polycarb.

[grp.boat]

thanks for your input.
i have settled for lexan margard. the margard bit is a scratch resistant coating. seems good up to now.

steve

[Robjl]

Sorry to disappoint but in my experience neither polycarb or acrylic will stand up to the abrasion of wipers. Why not try it..get a thin sample of both, tape it to the windscreen of the car and... go for it!
If the screen is kept clean the plastic will last a short time .. but if there is any grit the scratching will be instant and you will find that as you polish the scratches out (possible on the acrylic) the "view" will distort.
I have found that even dried salt will scratch both materials...
Solution : toughened glass.
Regards

[hombre]

:cool: TUFFAK CM2 is pretty amazing stuff. Really hard to scratch and it allows for some cold bending. It's a poly sheet, but it works great for windscreens, auto windows etc...
:!: http://k-mac-plastics.net/tuffok-polycarbonate-sheet.htm

Oh...did I mention expensive? But worth it, IMHO.

[fiberglass jack]

heres a trick to polish lexcan and poly all the comerscial polish and compound in the world cant beat whats in ur cupboard PENUTBUTER its a very fine compuond of crushed penuts and is equall to over 2000 grit it works great ant tastes even better

[DanishBagger]

Somewhere I read that polycarbonate should be polished straight one way, and then 90 degrees to that - at least that's what they do on the space shuttles.

I'll see if I can find a link.

[DanishBagger]

Found something that would work: Meguires Mirror Glaze. If you use the 16 for the rougher, and #10 to make it really nice, it should be possible to make it see-through, after the window wipers have marred it.