Feather out the edges of the swaths well with the knife for a smooth look. Step 10: Apply a third coat of drywall mud. Apply a third very thin coat of mud after the second coat dries. Use the 10 ...

Apply a thin coat of mud on top of the tape using a 6-inch or wider drywall knife and feather out the edges of the mud to prevent “ridges.” Clean your tools with water and let dry overnight.