Underbelly pan material

[benfrogg]

So I'd really like to have a belly pan installed. There is no cheap or free source of coroplast in my area. I've been trying to get my friends at the home depot to give me some old signs, but nothing yet.

I was thinking today, how about foil wrapped rigid insulation? The 1" stuff is plenty rigid for the task. It could be used without a frame for small spans. (I think) I'd have to use strapping or some other light material too hook it to the car.
It is light. Relatively inflammable. The joints could be taped with foil tape if need be.
It would be really easy to work with. It would be really easy to replace it if it broke too.

The question is, would it take moisture/road debris? How well will it wear?

What other options are there?
B