How to Varnish Railings

Preparation

• In order to get a silky finish, you have to start with a smooth railing, which means working it with sandpaper. You seldom need to use a machine for this, because it isn't difficult to draw the paper along the railing with your hand, curving it along the contours as you go. If the railing is rough to start with, however, a pass with a pad sander, using 120-grit paper, will prepare it for a final pass by hand with 150-grit paper. Spend extra time smoothing out parts of the railing where splinters could develop.

Staining

• If you need to alter the color of the railings to conform with the walls or other decor, you can wipe on a penetrating stain and let it dry overnight before varnishing. The stain may color certain types of wood unevenly, however, such as white oak, birch and pine. To avoid blotchiness, prepare the wood by applying wood conditioner before you stain. It partially penetrates the wood and keeps the stain closer to the surface so that it doesn't overcolor the porous areas. Applying conditioner isn't challenging -- just brush it on and let it dry.

Getting the Feel

• The keys to a silken-smooth railing are proper sanding between coats and control of the environment while the varnish is drying. The first coat is a sealer, and it will raise the grain, so after it dries, give the entire railing a light sanding with 220-grit sandpaper, then wipe it down with a rag before recoating. One more coat may be all the railing needs, but if you add a third coat, sand the second one in the same way. Keep the air as dust-free as you can while the varnish is drying. Any dust that settles on the finish will feel like sandpaper when you rub your hand over it.

Getting the Look

• Varnish looks best when you can't see brush marks. The first key to proper leveling is to use the right kind of brush -- natural bristle for oil-based varnish and synthetic for water-based products. The second key is to brush in long strokes. Apply the varnish on a dry area and spread it toward one that has already been coated. When both areas are uniformly wet, blend them with long, even strokes. You must work more quickly when using water-based products, because they dry more quickly. If you see any blemishes in either type of finish, remove them before the coating stiffens to avoid leaving permanent marks.