Your objective is to fill the low spots in the fabric weave without totally covering the high spots. When properly applied, SuperFil should be translucent over the high areas and fill the low areas. Do not use any filler, SuperFil or otherwise, to build up or shape leading edges or fillets. Fillers are not structural materials. After applying the filler material it s time for the composite builder s favorite activity-sanding.
Cheap sandpaper can leave scratches.
Change sandpaper grit gradually, about 100 grit at a time. This helps achieve smoothness. To find high areas or depressions in an area, use a straight edge or a template that matches a curved surface. Don t make the surface too smooth or it won t hold the primer coat. Stop sanding with about 240-grit sandpaper.