may 2014..using gorilla epoxy, glue glass to glass, used marine epoxy for copper to metal washer. the later worked just fine, but the washer to the glass did not. plate fell off. I checked and glue was soft. now using acetone to try and clean it up. what did I do wrong? I've read many hints and there are so many ideas on what glue to use. getting discouraged. all those pretty pictures and none of them mine.