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Hi. Fiberglass will do it great. You can use automotive primer and paint. Remember many cars are fiberglass made.For my cover I used the 1/2" plywood cause I can walk over the cover. I can even load some stuff on top of it. I am actually planning and upgrade adding some hooks or a side bar to secure more things on top of it. The only thing that you may need to think about using fiberglass is how to cover the piano hinge to make it water tight.The lamp I use is a 12v halogen, it was pretty easy to installed because this truck has a 12v plug in the trunk, so no need to add more cables. I am also thinking to change it for a led lamp that uses less space.
It is a good idea, I went for the vinyl fabric cause it was easier to work with, but maybe I try the fiberglass when a change it´s need
I forgot that part. My first try I used pieces of the same 1x2" wood screwed to the frame but it became a pain when you need to remove it.So now I used some screws with Tnuts across the frame and some steel angulars with a piece of rubber on the top to avoid damage the trunk. Because I did it as an upgrade my screws are out the vinil fabric, but you can do it below it to keep it looking nice.
Some pictures to give you an idea.
Hard Tonneau CoverView Instructable »
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