I used glasstac once. It doesn’t dry fast enough for me. Neither does Elmers School Glue which I sometimes still use. I also use Suave hairspray–or any extra hold hairspray without a strong scent. Keep in mind, though, that if your two pieces of glass aren’t completely flat, sometimes there isn’t enough surface contact for the hairspray to be effective. That’s when I go back to the gel glues.