How to Apply Polyurethane to an Old Oak Tabletop

Sand the oak tabletop with fine sandpaper, by hand, using short, light strokes. Sand it just enough to dull the surface. Wipe off the dust with dry rags.

Gently stir the polyurethane with a paint stirrer, making sure not to create bubbles. Pour into a bucket about half the amount needed to cover the surface, estimating as best you can.

Add an equal amount of paint thinner to the bucket. Gently mix them with the paint stirrer.

Brush the solution onto the table surface with a foam finishing brush, starting at one end and working your way across, stroking with the grain of the wood. Make the coat thin and even.

Let it set eight hours.

Lightly sand the dried polyurethane with fine sandpaper, again using short, light strokes. Wipe off the dust.

Brush on a coat of undiluted polyurethane, keeping it thin and smooth. Let it dry for eight hours.

Sand, wipe up the dust, and then brush on a third layer, also of undiluted polyurethane. Let it set for 24 hours.