Is spray on with compressed air OK? I used the SEM kit with supplied cheap gun on a PU bed. It came out very well. I got the material from Auto Body Depot ordered on line. If you Google "autocolorlibrary.com" that will get you there. Prep is same as paint. Clean, treat any rust and prime first. The primer needs to handle the hotter solvents in auto type paint.

The SEM stuff is catalyzed so it sets up faster and harder than the single stage products.