mark944turbo

GT Racing sells a polycarbonate windshild for 944s for $550. Is this a good thing to buy for a mainly street car? How reliable are they? The price does not seem too bad to me. Is it a good deal? What is the difference between polycarbonate and lexan?

944Play

[quote]Originally posted by mark944turbo:
Is this a good thing to buy for a mainly street car?
<hr></blockquote>
Not if you like to listen to the radio!
[quote]
What is the difference between polycarbonate and lexan?<hr></blockquote>
Lexan is polycarbonate. The other (weaker, but easier to work with) clear stuff is acrylic.
<img src="graemlins/beerchug.gif" border="0" alt="[cheers]" />

JimV8

This I know something about, LEXAN is GEs tradename for polycarbonate. The stuff is very, very tough, unbreakable, i use a circular saw to cut it. It can be cold formed but likes to stay flat. In natural state it yeelows like crazy and scratches by looking at it. You have to use UV stabilized two sides, LEXAN XL2, and surface hardcoat MR10 for any kind of exposure to the elements, It is electrostatic so attrats dust like nothing you've ever seen. It is very light compared to glass though. Except for racing it really is impractical for road use.

Chris 968

I have heard that the polycarbonate scratches much easier than glass. I heard from someone who used on their 968 rear hatch that it would not be good for a street car because it scratched easily. I sure it would be even worse on a front windshield.

Ryan Z

go GE.....they make/own everything....well, not really. I'm rooming w/ one of the VP's sons, lol

jim968

Plastic = soft surface; dust = hard, with sharp corners. Do the math...

Seriously, even your wiper blades will eventually scratch it. OK, actually, it'll be tiny grit particles that your wiper blades carry with them, but same result.

And while it's _really_ strong, tough stuff, I'd hate to learn what it's fracture characteristics are in a wreck.

Jim, "My opinions are my own, but I share them freely with anybody who doesn't run fast enough."

IceShark

Jim, they would be great in a wreck based on my experience. I used the stuff for sailboat hatches where you can get pounded by major waves for a long time. It works great if you have the edges tied down. We weren't all that interested on maintaining see-through clarity, just let daylight in.

I even experimented one sort of drunken night with the guys. Put (2) 1/2" sheets together and shot it with a .357 mag from 6 feet. Caught the bullet as it was just exiting the first sheet. No stress cracks around it, it sort of just melted around the bullet and stopped it dead in its tracks.

But forget it for a long lasting solution for a windshield. Even with the protective coatings it will scratch like crazy and the UV will still kill it. Plan on replacing an auto windscreen every year or two.

art

I thought there was a special coated version used for windshields. (Corvette?). I thnik I saw it in an Excellence article about a 356 built by Gary Emory(?) that used it.

Art

IceShark

Art, there are versions of lexan sheet product that have a thin liner laminated to both sides. The liner is more scratch resistant and has a UV blocker in it.

I have used that particular product for the sailboat hatches and I can tell you based on actual experience that the laminate helps but it is only delaying the inevitable. And I can't imagine that anyone would make a windshield without using the coated product. But nothing plastic is going to be remotely as hard as glass.

Lexan is ok for making lenses like turnsignals, etc. But you want to see crystal clear through your windshield and the windshield takes quite the beating from road rash and less than perfect cleaning methods.

I guess the bottom line is it WILL save weight but you better be prepared to suffer the worsening vision and replacement consequences. I think most street car owners would say forget it and take all the other steps you can do to get the vehicle weight down.

PCinDC

Ummm...am I the only one who thinks that we should probably save the firearm-stress tests for when we're...sober?

mouse

For a second I saw the "carbon" in "polycarbonate" and thought you had said carbon fiber windshield... and I pictured me driving in my car with this giant, opaque slab of gray and black checkered material in front of me, wondering where the hell I was going and then slamming into a tree.

mark944turbo

That settles it then. I hope I pass inspection with a 3 inch crack in the bottom left hand corner. (GOD DAMN HOOD SHOCK REPLACEMENT PROBLEM!)