Oh and as for primer, you don't NEED to use it, but it is highly recommended that you do since primers generally help paint stick to the surface. I usually use duplicolor sandable primer. They are lacquer primers so you can spray enamels, acrylics, and lacquers over them without worrying about it cracking. Now if the model is molded in colored plastics (red or green for example) then you should use duplicolor primer sealer instead of sandable primer. Hope this helps.