I'd double check that; 6-10 minutes should be the cure time, or working time. Full cure/dry time will should be 6-48 hours.
Remember when you get your windshield replaced, and you can't drive for 2-4 hours, and you r car just sits there, waiting for the urethane to dry.
I use urethane a lot for projects, and I usually let it sit for 24 hours before moving forward.