Fast drying time. For a textured wall, corners can be taped in one pass. To use UltraFlex, for example, you fold the tape at the center and trowel it into a bed of compound that has been thinned with water; then wipe down the narrow flange with a finishing knife, leaving most of the tape exposed (Figure 2).
Figure 2. As with conventional paper tape, UltraFlex is pressed into a bed of compound (top) and set with a taping knife (bottom left). But that’s where the similarity ends: Only the edges of the finish paper, which extend beyond the plastic backing 1/4 inch, are covered with a feathered coat of compound (bottom right). For textured walls, the corner can be painted after the mud dries; a smooth finish requires a second feather coat. Immediately apply a feather coat, again covering only the 1/4-inch paper flanges, and when the compound is dry the corner is ready for paint. A smooth wall finish requires a second feather coat at the paper flanges. Both UltraFlex and UltraCorner are easy to align over the corner, and because both the bed coat and edge coats are comparatively thin, outside corners require much less time to dry than corners trimmed with metal bead. Both of these tapes also have a much flatter installed profile than conventional metal corner bead. This reduces the amount of standoff created at the baseboard — a distinct advantage when dealing with stain grade trim.