Hi lads,I'm being watching all these proper spray painters on tv,shows like American Chopper,Biker Build Off etc etc and notice that after they've sprayed and lacquered a tank/mudguard etc they rub it done with fine sandpaper.Seen them do this on American Hotrod too.Can any experts on ere tell us what grade sandpaper this is,why its done etc etc.What the proper procedure when spraying???Is the paint rubbed down between coats etc etc???Any help from those in the know would be welcomed.Thanks in advance,Micky