Some Info About Painting With Enamel.

How would you add hardener to something out of a rattle can? If there's a way to do it, please let me know. I'd love to get rid of this one month curing time!!!

It's not that it won't stick. Its tacky and soft. I could skim the top off and still have uncured paint below. It's not that it's chipping off. It's just not curing.