OK, the problem above wasn’t so baffling; it just shows the JB Weld applied to the tank pickup, which was loose. Once in place on the car the pickup is held in place by the line leading to it, so the JB Weld is mainly providing a seal rather than structural strength. That said, I admire JB as a statement of hope; it’s often deployed as a last-ditch effort to fix something; fingers get crossed, everyone relaxes, congratulates each other and thinks “thank goodness”.
And then it fails. In my experience. Let’s hope this is different!