thisplace.com.au - Penetrating Sealers

Penetrating sealers are best mopped on using a clean string mop or long-handled applicator with a lamb's wool pad. Apply generous amounts of the sealer, making sure that final stroking is in the direction of the wood grain if possible. Any excess sealer which remains on the wood surface should be wiped up with a clean cloth or squeegee. A wide brush can also be used for application. After the first coat has dried it should be buffed with No. 2 steel wool. Buffing can be done by hand or with an electric polisher equipped with a steel wool pad. A second coat of penetrating seal will result in longer service life, but is not always necessary, particularly on close grained woods. Penetrating sealers can usually be refinished in heavy traffic areas without showing patch marks.

Polyurethanes

Polyurethanes may be applied using a brush or lamb's wool applicator. Because polyurethanes are a surface finish, care should be taken to work along the grain. Polyurethanes should be flowed on in a continuous manner so that the leading edge does not have time to dry out. After the first coat is thoroughly dry, buff it with steel wool, dust well and then apply the final coat. Varnishes Varnishes are usually applied with a brush and flowed on evenly and smoothly. The first coat can be thinned lightly so that it will penetrate into the wood like a sealer. After the first coat has dried, smooth it with fine sandpaper, dust well and then apply the top coat full strength. For the final touch of beauty and to protect the finish, apply one or more coats of good wax recommended for use on floors. Use either a liquid buffing wax/cleaner or paste wax. Use only brands that are designated for hardwood floors and if a liquid, be sure it has a solvent base, not a water base. Apply the wax after the finish coat is thoroughly dry and polish it with a machine buffer. The wax will give a lustrous sheen to the floor and form a protective film that prevents dirt from penetrating the finish. Some manufacturers of urethane finishes do not recommend waxing, especially for commercial jobs, because wax may make the floor slippery.

Wood floors finished with penetrating seals are not too difficult to repair should they show early signs of wear in the traffic channels or become stained or water damaged in localised areas. Floors finished with polyurethane or varnish can also be repaired, but lap marks or a splotchy appearance is more difficult to avoid. Floors finished with lacquer or shellac are nearly impossible to repair successfully. Finishes are best renewed when they begin to show signs of wear in traffic channels but before the bare wood is exposed. In this case, the floor must be cleaned of all dirt and debris, and all floor wax must be removed as it may interfere with the drying and adhesion of any new finish. Most of the wax can be stripped with rags kept moistened with mineral spirits or other paint thinners. The rest of the wax should be washed off with soap and warm water, doing the work as rapidly as possible so that the water will have little time to contact the wood.

After the surface has thoroughly dried, a new finish may be applied. If a penetrating seal is being restored, apply it to the worn areas as already described. Be careful to wipe up any excess, particularly in those areas where the old finish is still in good repair. If a surface finish such as polyurethane or varnish is being used, it may be a good idea to apply one coat of finish to the worn areas first. End all brush strokes at joints between boards. After the first coat is thoroughly dry, apply a second coat over the entire floor. If only a small stained or water damaged area is being repaired, try to remove the discolouration first. Use steel wool or a fine grade of sandpaper to smooth out the affected area and an inch or two of the surrounding floor. Remove all dust. Then brush on one or more thin coats of finish, feathering it in to the old finish to prevent lap marks. All plenty of time for drying between coats. Wax the repaired area if appropriate.

Source: Michigan State University