DIY Drywall Finishing with Metal Corner Bead
Also see:This page contains drywall finishing instructions for outside corners using metal corner bead. To finish outside corners with paper corner bead use this link. Use these links to finish inside drywall corners and finish drywall seams and go here for more about drywall finishing materials and techniques.
About Drywall Corner Bead
Outside drywall corners can be finished with either metal or paper drywall corner bead. Metal corner bead is the easiest to install and the best choice for durability and a perfectly square corner.
A slightly irregular corner formed by the drywall sheets is more easily covered with metal corner bead because the bead forms the wall corner. Some paper corner bead requires the drywall sheets come together to form a square to support the bead and form a corner.
Choosing Joint Compound
For a more durable corner you can use a first coat of setting-type joint compound or mud to install metal corner bead but work quickly to be sure it doesn't set before you're done. Ready–mixed joint compound can be used for the second and finish coats. It will also work for the first coat but it's much softer, takes much longer to dry and will shrink when used in a thick application like this. See Drywall Finishing Materials and Techniques for more information about drywall finishing tools, tapes and joint compounds.
Cut the Corner Bead
Cut a piece of metal drywall corner bead the length of each outside wall corner. Use a pair of tin snips or scissors to cut from each side of the metal and then bend the bead in the middle to break it apart.
Attach the Bead with Screws
Hold the bead against the corner pressing with a palm to flatten it tightly to both walls. Hold the bead tightly and drive a 1 5|8 or longer drywall screw thru the bead and into the framing. Drive a screw into the opposite wall, at about the same level, to hold the bead in place. Move along the length of the bead pressing at each point and drive screws into the bead and framing at about 12 inch intervals along both walls.
Sink the Screw Heads
Sink the heads of the screws deep enough to slightly kink the metal and make a small depression in the drywall. If the screws are not driven far enough below the surface of the wall, the heads will show through the mud.
Coat the Corner with Mud
Use a 6 inch drywall joint knife to apply a thick coat of mud in crossing strokes along both walls, from the top to the bottom.
Skim One Wall
Skim the excess mud from the corner, resting one side of the knife blade on the metal bead peak and the other against the drywall. Skim off the excess mud keeping the knife straight as it rides along the bead. Don't push too hard on the blade to avoid bending it.
Skim the Other Wall
Skim the other wall in the same way. Clean the mud off the joint knife frequently as you skim out the corner to avoid buildup. When you finish, go back to the top and run the clean blade along the whole length of each wall, from top to bottom, in one smooth stroke.
Skim the Edges
Skim along the edges of the mud to remove any buildup there before moving on.
Scrape the Peak
Scrape any mud off the peak of the corner bead and let the mud set.
Apply a Second Coat of Mud
When the mud is completely hard, use a larger joint knife to apply a second coat of mud. Use ready–mixed joint compound to cover the corner and overlap the edges of the first application with a thick coat of mud.
Skim the Second Coat of Mud
Skim the excess mud from both walls and then go over the whole length of the corner again with a clean blade to leave a smooth finish. Let the mud dry for about 24 hours and then sand it lightly with medium grit sandpaper. Use light pressure along the edges of the joint compound to avoid tearing into the drywall paper.
