For "Lexan" windows do you need to use a specific type/grade/thickness? The local hardware store has a couple different types for $42 a sheet (48" x 72" ?) Or do I need special "Race Car" Lexan for $75 a sheet?

Also, the cutting I can handle with a utility knife or jigsaw, but do I need to pre-drill the screw holes to prevent cracking? And will regular sheet metal self-tapping screws work? And should I use caulking to prevent leaks or screw it in?

I need advice from those who have gone before...

Thanks,
Rob

Rob,
There are really two types. Uncoated and coated. The coated stuff is referred to as Margard which means it has an abrasive resistant coating applied to it. keeps it looking pretty and scratch free longer.
I would pre-drill the holes and use a small nut and bolt if you can. If you use a screw it puts pressure on the lexan and will cause it to crack. You will also be able to see a discoloration in it from the stress. Look at some race cars at the track and you can see what looks like color waves originating from the screws, this comes from the way it is mounted.
Here is a small description of both types that I found on a manufacturers website.

Hope this helps.

Lexan polycarbonate is one of the most widely known "plastics". Lexan sheet with its unique combination of high impact strength, flame retardancy, and thermoformability makes it ideally suited for security applications. No other plastic can match Lexan's combination of light transmittance (clarity), and the ability to withstand extreme impact.

In thicknesses of .125", Lexan 9034 sheet will transmit 86% of the light. Lexan 9034 is UV stabilized, has a heat deflection temperature of 270 degrees F at 264 PSI, and has a smoke density rating less than 75. Lexan 9034 is engineered for window glazing as well as for sign applications. In addition to colorless (clear), Lexan 9034 is available in solar gray and bronze in thicknesses from .080" to .500".

Lexan Margard provides the superior impact resistance of Lexan 9034 with the advantage of an abrasion resisting state-of-the-art coating. Lexan Margard is unsurpassed in high vandalism areas such as schools, bus stops, public buildings, storefronts, shopping malls, and wherever clarity, safety, and security are required.


Properties
Excellent impact strength
Good weatherability
Ease of machining
Thermoformability
UV resisting

Thanks Tom,
I'll pick up a sheet at Lowe's and see what damage we can do. I'll see if we will be able to use nuts and bolts instead of screws. What about caulking to keep rain out? Thanks.

Rob,
You can use caulking. I would suggest getting some closed cell black foam. You can buy it with a sticky back, then all you have to do it stick it to the window frame. Much neater and cleaner than caulk. When you bolt the lexan in it will press against the foam and seal.



Tom

Awesome! Thanks.
I'm trying to find productive things for the kids to do to the GodsRods projects while I'm trying to figure out how to afford a reliable engine for the Duster.
I appreciate the help.