Sanding Grit Used When Skim Coating Walls?
I have a project where I will be repairing horse hair plaster and then skim coating with joint compound (roll the compound on the wall, use drywall tool to skim it off and then sand). I’ve read that I should use 200 or 220 grit sand paper when sanding it done. Frankly I find that even 220 leaves some marks. So I do the final sanding by hand and use 400 grit sandpaper which leaves a nice smooth wall for painting.
Is there any reason why I can’t go higher than 200-220 (meaning, what’s wrong with using 400?) I find articles that say not to use more than those grits, but not why.