You need to use a dual action type sander. Straight sanding will never get it looking good until the finish is applied. I use a Porter Cable with the loop disks. Take it down to 220 and start finishing. When I hand sanded everything I wasn't even happy with 400. Now I only hand sand after I coat the bow. You can still spend pleanty of time sanding because you start with 890 and go through all the grits.god bless you, Steve