Finishing drywall corners can be a challenge if you've never attempted it. It takes practice, a certain amount of skill, and the right tools and materials. Use the following information to practice. When you're satisfied you have the technique down pat, you'll be ready to start your first drywall project.
Step 1 - Choose Your Corner Bead
Corner bead is a key factor in finishing a drywall outside corner. Depending on your preference, you can use a bead that is vinyl, metal, or paper faced. If you prefer the type that is easiest to work with, you best bet will be the metal, paper faced type. Partly, this is because instead of attaching the bead with nails, you apply it to a bed of wet joint compound that holds it permanently in place when the compound dries.
Step 2 - Install the Corner Drywall
Drywalling a corner properly requires that the corner's framing be installed plumb and tight. Before attaching drywall, use a carpenter's level to be sure the frame is plumb. In assembling the corner to avoid edges that overhang, first cut one board so the corner stud edge and board edge are flush. The next board should be cut so it overlaps part way onto the first board. Use screws to secure the edges. Screws should be spaced 12 inches.
Step 3 - Apply the Adhesive Coat
You can get corner bead seated on the wall by thinning the adhesive coat before applying it. It should be the approximate viscosity of a thicker pancake batter. Then apply it in a swath to the drywall on both sides of the corner. Make these swaths each about two inches wide, forming layers that are uniform. Do this by holding your drywall knife at a shallow level and apply a somewhat light pressure.
Step 4 - Add the Bead
Fit the corner bead onto the corner and apply a slight pressure with your finger or thumb against the bead to push it tight from bottom to top of the bead. Then, seat the bead paper in the adhesive, using pressure slight enough that you don't make indentations in it.
Step 5 - Add Drywall Compound
Apply the first of two coats of compound by using your taping knife to spread the compound on one side of the corner, so the bead nose is covered. Then, with the knife held at a shallow angle, draw it in a single pass along the inside of the corner bead from top to bottom. Next, hold the knife at a 45-degree angle and again draw it against the inside surface of the bead. Apply pressure on the inside edge of the knife without allowing the outer edge to touch the compound that has been laid on the drywall and bead. Finally, do another pass with your knife, with a slight inward pressure. When finished with this pass, you should be able to see the bead nose.
Step 6 - Finish
After filling voids in the applied compound and skimming, allow the compound to dry, then use fine sandpaper to smooth rough spots.