Anybody know anything about undercoating?

After many hours of scraping and sanding I finally got all the old undercoating off last night and spray new on. I used westleys rubberized undercoating. That was pretty late last night, but sixteen hours later or so it still isnt dry. It was 90+ degrees all day, this stuff shouldve dried. Its not sticky, but I can make imprints with my fingernails and it feels like its not completely dry when I do that. I really dont want to scrape all this off and do it again. Anybody know how long this stuff takes to dry all the way?

Depending on where you live it could be "not" dry yet due to if there's high humdity. Also...depending on your thickness.

that stuff take a long time to harden if you sprayed it on thick. give it time it'll harden up.