Before it has had time to dry, however, it is rubbed vigorously with cotton waste, dipped in pumice and water, to bring out the highlights. After drying, the surplus pumice is brushed or wiped off and the surface waxed. Wallboards. The term "wallboard" is sometimes used to include all classes of building materials which are applied to walls in large sheets; at other times it is used to designate only those materials composed of wood, cane or other vegetable fibers and having a soft or semisoft surface. Here, however, we use the term to cover the wall materials sold in large panels except plywood; in other words, the "softboards" and "hardboards" made of compressed fibers and plasterboard, or gypsum board. Wallboards are manufactured in various thicknesses ranging from % in. in the hardboards up to i in. in the softboards. The typical panel size is 4 ft. by 8 ft., but other sizes are available. The 16in. width is sometimes referred to as "planks." Some wallboards are sold unfinished and are designed to be covered with paint or wallpaper after installation. Others are factoryfinished in various colors, plain and patterned, including simulated wood grain. A class of wallboard known as "tileboard" has a hard glossy finish and is grooved to give the appearance of a tiled wall. Generally speaking, wallboards are attached in the same ways as plywood (see above). They may be applied over old walls or directly to furring strips. Tongues and grooves and various other edge treatments (Figures 9.17 and 9.26) Souare Recess With Bead. Fig. 9.26. Edge treatments for wallboard. 476 FURNITURE MAKING AND CABINET WORK Courtesy BUSINESS OF BUILDING Magazine, United States Gypsum Company Fig. 9.27. Applying cove molding to finish wall and ceiling joint. are available, which facilitate attaching the panels, while at the same time making the joints attractive. Concealed nailing through some of these joints is possible using nails specially designed for nailing of wallboard. Plasterboard is applied to walls and the joints are covered by the methods described above under ceilings. \\'<у Ч \ \- >' II 1 И ' 1 у 1 Fig. 9.28. Top row: Cap and Base Trim, Metal Inside Corner, and Metal Outside Corner. Bottom row: Metal Divided, Metal End Molding, and Bathtub Molding. INDOOR REMODELING 477 Specially designed cove moldings (Fig. 9.27) are available for use with this material. Wallboard panels and planks can be cut with an ordinary handsaw. When sawing long lengths of flexible wallboard, it is a good idea to clamp the panel between boards to add rigidity. Soft wallboards should be conditioned for a day or more, by laying them singly around the room where they are to be installed. In very dry weather they should be sprinkled lightly and piled flat for a day or two for conditioning. Regardless of how the joints in the wall are treated, a molding is customarily used at the ceiling line to cover the joint between the wall and the ceiling.