I agree with Sevt-Chevelle. Im also in the collision industry, 400 grit will show sand scratches, espessially on silvers, but the use of sealer will eliminate sand scrathes.
In our shop(before it burned), we sanded everything with 400 & used sealer. Recently I realized that 600 works better, & you dont have to use sealer. Unless you have a color that doesn't cover well, then Id use a tinted sealer.
