This is exactly what I do. You aren't supposed to use E6000 with the foil backing.
Originally Posted by lilredsmiles
Any time I've ever tried to E6000 a flatback rhinestone, it caused a chemical reaction with the foil backing that made it look all warped. I use gem-tac with flatbacks. It works well. The rhinestone guy says it works as well as hotfix (therefore hotfix must be the "gold standard")