I have successfully used Epoxy to repair my shells. I actually have two shells for my Evolution - I had picked an extra one up because my first one got cracked pretty bad. I had two cracks on either side of the robot by the wheels. I've been using the repaired shell this season and so far it has held up without an issue.
I will move the post I made on the other forum to this one, but check out the post related to my latest height mods - I had offered to repair shells and repaint a different color if people wanted to do that. The shell that I repaired I also repainted a metallic blue - looks awesome and fits with the Indianapolis Colts too

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Here are a couple pictures:

