In this Autos, Motorcycles & Planes video tutorial you will learn how to feather edge paint to prepare a damaged car for primer. Feather edging is the process of feathering or layering each layer of coating in order to prevent a rough edge. Use a 6 inch DA and 150 - 220 grit sandpaper to feather edge the paint edge. Apply the sandpaper all along the edge of the paint till the edges are smooth. Feel it with your hand to ensure that all the edges are smooth. Feather each layer of paint at least a quarter of an inch. This will eliminate any hard rough paint edge.