Your application time was too slow. KBS is an air dry clear and is very volatile, so it will start to solidify quickly. I've had great success with this product!
The playfield needs to be properly prepped just like if you where going to spray automotive clear; needs to be free of wax/oil contamination.
You need to apply KBS with a foam roller quickly; it should take you 2-5 minutes to cover the entire playfield.
I don't recommend doing this outside, but in a garage or tent at the manufacture recommended temperature. The product is very sticky and will stay that way for a few hours after application. Applying this outside uncovered is asking for bugs and dust to get on your work.
The KBS clear will be good to wetsand after 48hrs.
Expect to use the entire pint on one playfield. It will take about 5-6 applications.

Before and after pics, proof that KBS works.

95590290_10117157439236054_337963949955743744_n (resized).jpg

98344184_10117248694569634_233122320791633920_n (resized).jpg

The key difference that makes KBS attractive is low cost of equipment; i.e. paint pan and foam roller. And safety, because you're not atomizing toxic paint in the air and no overspray getting all over.