Step 9
After your third (or more) coats of joint compound are dry and your satisfied the patched area is as flat and level as possible, sand the entire area lightly with a medium – fine sanding sponge. Tip – After sanding, use a damp sponge and go over the entire surface to remove dust. This also will help to make a smooth transition to the existing wall surface.
Once again, check the entire surface with the edge of your knife or trowel and sand level or apply an additional coat of joint compound to low areas if needed.
Tip – DO NOT try and rush this step. Spend as much time and/or apply as many coats of joint compound as needed to ensure a level surface over the entire patched area.