Mod Material Other Than Coroplast?
 

Coroplast is the material of choice around here....I picked up a sheet of this yesterday and plan to use it for a grille block. Has anyone used it before? Are there other materials that are commonly used?

Tygen1 used the same material for his rear skirts and painted them black.

I went and dug up that thread. Looks like it turned out pretty well. As he did, I bought a can of black spray paint designed for plastic. :)

ABS plastic is also a good choice. It comes in a few thicknesses, my skirts and grillblock are made with 1/8in abs. It's flexible to a point and if you heat it you can bend it more. Unlike coreplast it's a bit harder to cut with a boxcutter. Coreplast cuts like butter comparitively, you have to score and score and score to get through the ABS (or just use a jigsaw). But ABS it more durable than coreplast which punctures rather easily. Also when I use coreplast I usually tape the leading edge because I don't want air getting caught up in the corrugation.
At my plastics supply store ABS 4x8's are $24 but coreplast is only $14 so coreplast is much cheaper.
The FRP you linked to is fine. Advantages would be price and availability (easy to find)
The disadvantages would be lack of color choice and it's very brittle so bending beyond mild curves would be tough.

My friend just picked up a bunch of alumalite. It is like coroplast, but thicker, and with .019" aluminum bonded to both sides. We thought we could bend a curve in it over a barrel... this stuff is STIFF! The two of us could not for the life of us put a bend in the alumalite, and that was going the weak way! We are going to try using a sheet metal press to make bends and a skill saw to do the cutting.
He also got a single sheet of polyvynal. this is more of a foam core with thinner aluminum bonded to both surfaces. This was much easier to bend, but still much too hard to get a 10 inch radius out of it.
I would say either of these materials would be much more ideal for building a semi permanent/permanent aeromod, where the coroplast is fine for small spans, but bends easily and requires support.

That alumalite would make an awesome belly pan.
Where did you find it ?

Alumalite came from a guy that puts up and takes down signs. When he takes them down, they are no longer needed and he sells them for $10 a sheet. He advertises on Craigslist when he has a bunch gathered up (every couple months). I would guess that you can contact local sign shops and ask if they have any for cheap that you can buy. You can even peel off the vynal that they print with if you take the time.

I used the same material Abell75 linked to for the interior walls of the topper on my previous pickup. I can confirm from experience that it will not take too much of a bend without cracking. It is also a little on the heavy side, which is why I didn't use it on my new topper for my new truck.