I went through a "rock" incident a couple of years ago. I replaced with Lexan and it still looks as good as the day I replaced it. You can find my original post on the product & on making and installing a Lexan windshield below:

Note(10/21/03) my original concern on scatching has not occured, as long as your windshield is not dirty when wipers are used I don't believe that it will scratch. Just to be sure, I just use Rain-x and drive faster

[From earlier post]

RE: Windshield replacement

I had an encounter with rock and my windshield last weekend and after doing some research and receiving advice from some other members I use the following solution:

Researching replacement of the glass with glass meant $108 - $385 for the glass plus shipping (about $100) pretty expensive. The other option is to use Polycarbonate (Lexan) @ about $125.

I ,like many others, opted for the Lexan (270% stronger than glass and cheaper) however it's not DOT rated due mainly to it's susceptibility to scratching. Even with the Abrasion resistant coating Lexan is NOT recommended for use if you are going to use wipers, it will scratch.

Tools:

• 5' - 6' table with carpeting on top to make the job easier
• 52" x 17" x 1/4 Lexan AR (abrasion resistant)
• Spray bottle with soapy water
• Phillips screwdriver
• 1" Masking tape
• Butcher paper
• Sharpie marking pen
• A little patience

1) remove the old windshield from the 2 arms by removing the 4 screws on each arm.

2) remove the 4 screws at each corner of the windshield frame ( these screws go into a brackets on each side and I found that it was easiest to take out all 4)

3) lay the windshield curve down and carefully remove the bottom frame, starting at on end and slowly working toward the other, DO NOT PRY against the glass and try to not to twist the bracket, either may cause the glass to break. Note: once you get the frame started off spray some of the soapy water in the channel to help the gasket to release

4) Follow the same process as 3 to remove the main frame

5) At this point you should have the old glass out and in one piece, Place the butcher paper under the glass (Glass again curve down) and starting at one end tape the paper to the glass making sure that it is firmly against the surface. Using the sharpie trace the pattern onto the paper.

6) Now this is IMPORTANT, cut the pattern you have just made to the INSIDE of the line. If you cut to the outside leaving the mark on the paper your pattern will be to big.

7) At this point you have two options: You can transfer and cut the pattern yourself to the Lexan or you may be able to have your plastic supplier do it for you.

8) If you choose to do it yourself, you will need a good jig saw with a blade suitable for plastic. Lay the pattern out on your sheet , taping it in place, and trace it.

9) Using your jig saw and taking your time, cut out the pattern this time cut directly on the line

10) remove gasket from the frame, or from the glass depending on where it remained, being careful not to tear it.

11) Take the Lexan and roll the protective paper off of the edges about 1" and place the main frame gasket (the larger piece) around the edge or the Lexan.

You will need an extra set of hands for the next part

11) Spray the gasket the soapy water and position the frame with the legs up and with the gasket down position the Lexan so that one gasket side is against one leg and the bottom is parallel and slightly above with the frame (since the frame is curved and the Lexan is flat it will not yet be in the channel) bend the Lexan into place on the remaining leg while insuring that the bottom is inline with the frame channel. At this point the Lexan should be sitting above or partially in the frame channel , spray it down one more time with the soapy water and firmly and evenly press the Lexan into the channel.

12) You're almost done, take the remaining frame piece and loosely replace the end brackets and perform a "dry fit" to insure that the brackets will fit ( I needed to bend my brackets slightly so that the hole would line up)

13) Place the remaining gasket on the exposed edge of the Lexan spray it with soapy water and evenly press the remaining frame piece into place.

14) A little manipulation may be required to get these tiny screws to start. I used an awl to align one hole then inserted the screw in the other.

15) Well at this point you have your glass replaced and all that's left is to re-install it on the car, then peel off the protective paper and go.

Total cost was about $130 from Tap plastics, but I'm sure you can probably get it from other suppliers just check your phone book.

Good luck,

Mike