Fascinating... I guess someone had to do it.
JB Weld is great stuff- I keep a few sets of tubes in the emergency gear- but it would never have occurred to me to use it this way. I don't recall ever reading that it was "food grade", and I have to wonder...
It's an interesting experiment, but between the roof-flashing-thickness aluminum and the JB Weld, I'm afriad I wouldn't want to rely on it's staying leak-free for a serious trip, even if there aren't any toxicity issues.