I am having some trouble with Rust-Oleum industial enamel. I am painting cast iron that has been sand blasted and cleaned with lacquer thinner. I followed the directions and painted in low humidity and about 60 degrees. I primed several coats of primer and about 2-3 coats of green within an hour. I ended up with paint that had an orange peel look and did not harden well. On some other parts I ended up with primer that has been sitting 10+ days and has not hardended up. I can still scratch it with my finger nail. I have no idea what the problem here is. Any help would be great. I was thinking of setting the parts out on the driveway in the heat to try to bake that paint hard. I have had good luck with basic rust-oleum paint and was hoping that the industrial enamel would be better than the standard rust-oleum.