OK, I was concerned about the JB weld expanding at a different rate so it might come loose but maybe the temps are not big enough to make a difference. I have fixed lots of things with JB so I suspect that will do it.
I got this refractory cement in powder form. I may play with it just to see how it sets up. It did not cost much. The claim is that it withstands 2000 deg but if paint won't stick to it, that's not good.
This thing had been working fine with metal tape holding the top in place.