Expert: William Forster - 2/25/2007

Question
I never have any luck sanding body filler edge to blend in with surrounding metal.  I always have an edge.  This also happens when I am sanding old paint, to try to feather it in so I can refinish.  You always seem to see my edges.  What am I doing wrong?  Should I sand in a particular direction?  I have many air tools (file, DA sander, etc).  Am I just using these wrong?

Chris

Answer
How are you prepping the surface for filler? Are you using a quality filler? Bondo brand filler is horrible crap. USC fillers like Rage sand great, and will stick to galvonized steel. Surface prep includes grinding to bare metal with 36 grit discs, then feathering back with 80 D/A. Rough out filler with 36, followed by 80, followed by 150, followed by 320. Expext to apply 2-3 coats of filler, save the fine sanding for the last coat. Now, feathering. If you are seeing rings in the paint a couple days after it dries, this is called mapping. You aren't following your initial sanding with a fine enough sand paper. Use 80 first, followed by 180, followed by 320, all on a DA sander. Use primer surfacer to prime. Spray a guide coat with some spray can paint, just a dust coat, then sand he primer until you no longer see the guide color. If you still can"t get the paint to feather, the paint is at faault, and needs stripped. Bill