Wood – apply water based polyurethane over oil based polyurethane and vice versa

hardwood-refinishingpolyurethane

I can see brush strokes on a dining table from a previous application of polyurethane.

I want to sand these and re-apply polyurethane. I do not know whether the previous application was a water-based or oil-based product.

What should I do?

Best Answer

What you will want to do is to get a polyurethane stripper with brush, a pair of rubber gloves, a scraping tool, fine grit sandpaper (200), a clean cloth, and a well ventilated room.

Start by applying the polyurethane stripper liberally and evenly over the wood using the brush. Let it stand for about 5 minutes or whatever the directions instruct you to do.

Using the scraping tool, gently scrape off the polyurethane in the direction of the wood grain, taking care to remove the scrapings as you go along using a clean cloth.

Once the scraping is completed, lightly sand the wood in the direction of the grains until the surface is smooth.

You're now ready to apply the finish of your choice, whether it be polyurethane, a stain, or paint. :)