In order to eliminate the appearance of any remaining ripples and waves in our sheetmetal, the students each took a turn at spraying Alsa's APs-22712 urethane primersurfacer. These types of primers, also called buildup primer or filler primer, are meant to be sprayed on in relatively thick coats and sanded flat once they've cured. They level out as they cure, filling sand scratches and small nicks and dings. The students sprayed the car with two coats of primer using a 2.5 fluid tip in the spray gun. Compared with the technique used to apply the sealer, basecoat, and clearcoat, this is like spraying with a fire hose. Prior to being removed from the paint booth, the car was again sprayed with a light guidecoat, the reddish splotches you see in the photo.