Sanding sealer: Varnish's undercover agent

Chances are, you've probably used polyurethane varnish or some other clear topcoat to protect wood surfaces, such as tabletops, cabinets and shelving.

But are you familiar with something called Sanding Sealer? If not, you should be.

Sanding sealer is a fast, economical way to seal wood and prep the surface for the application of a clear topcoat finish.

The sealer is slightly thinner in viscosity than varnish, so it soaks into bare wood quickly to completely seal the wood grain, which is critical for creating a smooth, even topcoat.

The main reason I love using water-based sanding sealer is that it dries in just 20 to 40 minutes; slightly longer if it's a very humid day or if you're using oil-based sealer.

You can seal bare wood with polyurethane, but that'll require waiting at least three or four hours--often much longer--for the surface to dry.

With sanding sealer you can typically seal the wood and apply the first topcoat of finish within an hour or so.

Sanding sealer can be applied with a brush or pad, or even sprayed on, but I've found the quickest, neatest way is to use a 3-inch-wide trim roller.

Simply pour a little sealer onto the surface and spread it out with the roller. Then, use a 4-inch-wide paintbrush to lightly brush the surface, producing an even coat of sealer.

Once the sealer is dry, lightly sand the surface with 180- or 220-grit sandpaper. Be sure to wipe away the sanding dust with a tack cloth or damp rag before applying the topcoat finish.

Sanding sealer can be used on all softwoods and hardwoods, and even particleboard, plywood and hardboard. A quart can costs between $8 and $12, depending on manufacturer.