JZX250

Hi guys, I also have had a problem with DN top coat. I am spraying it with an airbrush, I have to thin it 30% to get it to spray a nice coat. The first time I used it, it set up beautiful, hard as rock and water clear. The last two times I sprayed it, it still looks great, but 2 or 3 days later it still isn't hard. I can't figure out what I'm doing wrong. I thinned it with lacquer thinner each time. Any help would greatly appreciated. If I can get it to work like it did the first time everytime it would be the best clearcoat I've ever used. One more thing, this is my first post, but I have been learning from you guys for a long and I wanted to thank all of you for the great info. This has got to be the best site on the web!! JZX250