Orange peel was my second problem. It is caused by several factors: too much air pressure, holding the gun too far from the surface, under-reduced paint, or using the wrong temperature reducer. Because I used the correct reducer, I can't use that as an excuse. In hindsight, I probably didn't reduce the paint enough. The fix for both the orange peel and the sand scratches was to wet-sand the car, and this is what you need for that job.