When you are sanding your last primer coat, and you are down to the fine grits (400-500 wet), are you supposed to still sand in a X pattern?

:confused:

Yup, I like to make a light cut front to back, the length of the panel to establish and verify straightness, then go to an x pattern. Another easy thing to do to that really helps finish the surface off prior to paint is to take three grey scotchbrite pads and stack them so you have a good cushion and rub the entire car down after the blocking is done, make your strokes with the length of the car. The scotchbrites will mellow out any cut marks from a block edge that may be there and also provides the perfect texture for topcoating. Watch your sharp bodylines with the scotchbrites as they will get slightly rounded if not carefull.