How to Fill in Ridges in a Bullnose Arch Bead

Place the end of a tape measure at the base of the archway's left side, as you face it, where it meets the floor. Stretch the tape measure up and along the arch to measure the total length from the bottom left side all the way over to the bottom right side. Use a ladder to stand on if needed.

Lay strips of flexible plastic corner bead on a worktable, and measure enough of them to equal the archway length you determined previously. Typically, at least two to three strips of corner bead are needed. Mark each bead that requires cutting, and cut it to the correct size with tin sips.

Place the first strip of flexible plastic corner bead at the left side of the arch with its rounded side facing outward. Center the strip perfectly over the archway's corner, and secure it in place using a staple gun and 9/16-inch long staples spaced every 3 inches along both sides of the bead.

Install additional strips of corner bead along the entire arch, bending the strips as needed to place them along the curve. Use the same methods you used to install the first corner bead.

Spread plastic tarps on the floor under and near the archway to protect the flooring. Scoop about 1/2 cup of joint compound with a putty knife, and spread it thickly over the corner beads to fill in the ridges along the beads. Continue spreading more joint compound until no ridges or beads are visible. Wait 24 hours for the joint compound to dry on the archway.

Put on a dust mask and safety glasses. Sand the archway using fine-grit sandpaper, concentrating first on the flat portions to make the dried joint compound smooth. Then use the sandpaper over the center of the rounded bull-nose portions, sanding up and down those areas to create a perfectly rounded, ridge-free archway.

After you finish sanding, the archway is ready for primer and paint.