Preventing Bubbles In Urethane Floor Vinish

Stir the can prior to use and take your time.

Preventing bubbles in urethane floor vinish.

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 only remedy is to sand out the bubbles and apply another coat of finish more. Applying polyurethane and most other finishes in heavy coats creates bubbles puddles and runs and becomes a defect in and of itself.

To prevent air bubbles from occurring at all follow these tips. Nobody wants to do all the work of refinishing and end up with bubbles in the finish. When the finish hardens you have to sand them out and apply a new finish. 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. Stir the contents instead with a paint stick in a gentle swirling motion. Resist the temptation to shake the polyurethane prior to use. Sanding between coats with very fine grit paper 220 and finer.

I had similar problems with very fine bubbles in topcoat. Heavy coats of paint levels as it dries flattens out to hide brush marks and minor defects. Brush out bubbles in a fresh polyurethane finish. 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. Finish brushes delicately lay on a thin clear coat to accentuate the surface below. Very smooth surface preparation. There are several things that can cause bubbles in the finish.

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.