The effect of the arch is transitioned by the rounded corner. Credit the vinyl arch bullnose bead. Which forms an integrated curve with a uniform appearance.
If you have yet to do so, see installing bullnose corners. Where the arched bead differs is in setting the radius — with the bead halved into a continuous side and a tabbed side. To install the bead simply:
1) Measure off the bead for cutting, and be sure to give enough distance for setting it into the arch. Usually the bending radius takes a little more than many first-time installers plan. Therefore, sizing with an overcut may bring you right in there.
2) Turn the tabbed half of the bead onto the straighl wall side. This is the flat, vertical plane, bordering the inset of the arch. The tabs will seperate to accomodate the arch. The nosing should be mounted from a single continuous piece.
3) Progressing in a single direction, screw or tack in-place through the holes, penetrating wood studs (if there is a retainer strip along the bead edge, these must be pulled). Miter the corner bead at the angles — at the bottom of the radius and the beginning of the straight bullnose — typically this is the top of the straight verticals.
4) With both sides of the bullnose fastened, knife on mudd with 8″ blade or more at the right consistency to embed the tabbed cutouts and holes of the rounded bead section onto the wall. Smooth with a flexible, rounded tool, helps meet the rounded radius. Let to thoroughly dry.
5) Delicately, scrape with a knife for preliminary smoothness, taking caution not to hit the underlying tabs. Always handling the knife level.
6) Re-skim as needed and sand smooth with a hand sander and preferable a sponge block or round pad for the curved wall. Being careful not to demarcate lines into the curving surface with a hard hand or flip-floopy pole sander.
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