So I finally put one together
I'm doing a quick run on the San Juan in a couple of days and I really wanted to take pad with me. I'm starting grad school in about 10 days, and I haven't had time to work on my plastic welding skills, so I decided to try a glued pad because it seemed more straight forward and there was less of a chance that I would totally screw it up. If it didn't hold up, I could just cut off the old tarp and try again, re-using the interior pad and valves.
I think the first attempt turned out pretty good. I placed valves on the sides, on either end, so I could blow air through and dry out things if a little water entered. I went with white, for heat reasons, but I'm sure it will look pretty dingy soon.
The pad is 3" x 27" x 82", There was just enough material to do a 2" wide seam down the length of it, and the ends have 2" seams as well. It's a pretty tight fit. If it holds up well, I'll put some corner patches on it, and maybe pull out the sharpie to draw a logo, I'm thinking my family's ranch brand would be cool... the Bench Lazy R. I'll post a few more photos soon, but so far I'm happy.
I assembled it during my daughter's nap time, and all told, it's about $70 of materials, with the foam running almost $50.