A buddy of mine is fond of Rustoleum, and he called them and asked about a hardener. They said "nope - none available. period."
He says it can take up to a year to fully harden. Oy.
-Michael
Sounds like Rustoleum needs a better PR man to answer the phone. Did he have an India accent and say that his name was "Kevin"?

(No offense to anyone from India, or anyone named Kevin.)
Carl