I do not think JB weld will make the frame any worse, but the idea of using it for frame repair is nonsense. JB weld is just an epoxy and has nowhere near the strength of a proper welded joint or the original tube. Nowhere near meaning like less than 1/100th the strength, if you are lucky.

You would be better off just getting a skilled aluminum welder to put a patch over it... but that ist't too good either.