Have a nice pair of Italian fisherman's sandals where the entire sole detached from the leather uppers.  Cleaned and sanded top and bottom and applied shoe goo sparingly to avoid spillover.  Then stood motionless in sandal for about half an hour.  Adhered perfectly and is not coming off.  Great product saved me $100 on a new pair of quality sandals.  BTW the same thing had happened to the other shoe last year.  I took it to a cobbler who fixed it for $20.  My repair was not only far cheaper, it was much neater and better overall.  The cobbler also used an adhesive glue but put less care into it.