I used the Flex Seal this weekend, but not on the
scamp. I used in to repair the bottom of a 1940s metal cooler that had some spots rusted through the outter layer. It worked well. It sealed it completely and then accepted the Rustoleum primer and top coat. I'm sure it will last longer than I do.
However, I won't be using it for the rivets. The spray foams up and would be hard to control over just the rivet without fear of drips and blobs. It dries to a clear milky color. I think it may come in a brush on product too, which may be easier to control the product in a small area like I have.