Preventing Bubbles In Urethane Floor Vinish

Diluting the poly.

Preventing bubbles in urethane floor vinish.

Stir the can prior to use and take your time. Some brands of finish are known to bubble more than other brands. Applying polyurethane and most other finishes in heavy coats creates bubbles puddles and runs and becomes a defect in and of itself. Stir the contents instead with a paint stick in a gentle swirling motion.

Heavy coats of paint levels as it dries flattens out to hide brush marks and minor defects. Resist the temptation to shake the polyurethane prior to use. I was applying semi gloss finish polyurethane on an oil stained birch tabletop. Stain that has not dried before the first coat of finish can cause bubbles.

The stain may feel dry on the surface but still be wet below the surface causing the finish to bubble. I had tried every option i could think of. The most common causes for bubbles are shaking the can and improper brush prep you don t stick a brush into the finish without first soaking the bristles in mineral spirits for oil based polys or in water for water based polys. Finish brushes delicately lay on a thin clear coat to accentuate the surface below.

Nobody wants to do all the work of refinishing and end up with bubbles in the finish. Brush out bubbles in a fresh polyurethane finish. Sanding between coats with very fine grit paper 220 and finer. Very smooth surface preparation.

To prevent air bubbles from occurring at all follow these tips. I had similar problems with very fine bubbles in topcoat. This happens to floor finishers who drag the finish applicator aggressively and then must stay off the floor until the finish dries. However if you re not careful small air bubbles can mar the beauty of the finish permanently.

There are several things that can cause bubbles in the finish.