What Kind of Clear Polyurethane Is Good for Table Tops?

Cost

• Water-based polyurethanes tend to cost a bit more than oil-based polyurethanes, but the difference is minor if you need only a small amount. The cost difference becomes more apparent in large projects because more coats of water-based polyurethanes are necessary to provide the same level of protection as fewer coats of oil-based polyurethanes. A small end table could be finished with one can of water-based polyurethane that would cost only a few dollars more than oil-based polyurethane. If you want to finish a large, multileaf dining room table, however, you would need multiple cans, making water-based polyurethane the more expensive of the two kinds by a moderate margin.

Application

• Both water-based and oil-based polyurethanes can be brushed or sprayed. The water-based formulas are thinner than the oil-based formulas, and so they are more prone to drips and runs. They also may show more brush marks. Oil-based formulas may bubble more often than the water-based formulas if proper technique isn't practiced. If your brush skills aren't up to par, the spray can varieties give you a better chance at a flawless coat, but the finish is more likely to come out uneven across large areas such as tabletops due to overlapping spray strokes. The best option may be to use a spray for tables' legs to avoid drips along turned areas and to use a brush-on formula on tabletops for a smoother finish. Oil-based formulas produce a very noxious odor, which is a consideration if your project area has inadequate ventilation.

Appearance

• Despite the fact that both finishes are clear, the color of the finished product is very different depending on which product you use. An oil-based product adds a warm amber tint to wood and accentuates its grain, and a water-based formula dries crystal-clear with no color enhancement. Warm-colored wood such as maple looks better with the oil-based amber tint. Very pale wood, including pine and aspen, may look cleaner with the colorless water-based finish. See the wood swatches in the stain aisle at your home-improvement store to assess the difference.

Protection

• Oil-based polyurethane provides a stronger, more protective finish than water-based polyurethane, but applying extra coats of the water-based polyurethane can result in equal protection. Although a table may require two or three coats of an oil-based polyurethane, the same table may need four or more coats of a water-based polyurethane. The hardness of the final cured finish is about the same between the two kinds of polyurethane, but the hardness may vary slightly among brands. A very hard finish scratches more easily than a softer finish; a finish that is too soft, however, gouges easily. Follow the curing instructions on the polyurethane can to reduce the chance of marring the finish.