Q: One visitor asked, "Our 50 year old oak strip hardwood floors were recently sanded and refinished with urethane. Due to some minor items we had the flooring company come back a second time to fill in some gaps and buff and put another coat on. After the second time we now have very visible air bubbles in our urethane finish (they were not present the first time). I suspect they hurried to complete the job. What is the best way to remove the air bubbles?"

A: In my opinion, the air bubbles that have appeared after the last coat of finish (I call them fish eye bubbles)are not necessarily, and not likely the fault of the person applying the polyurethane. Generally, as each application of finish is applied, it tends to dry faster. So the first coat takes the longest, with each following coat drying a bit quicker. In this case, it did not have time to flow out level and allow any air bubbles to break before it set up. I would suggest letting the floor dry for at least a week, and trying again. I would not use anything more coarse than a 180 grit screen with the polisher. After thorough cleaning (vacuum up all dust and wipe with a cloth dampened with water) apply another coat of finish, with all windows in the area closed and all sources of ventilation stopped. After at least 2 hours, some ventilation can be allowed to help dissipate vapours. If there are any windows allowing direct mid day sunlight to hit the floor during application, it is a good idea to cover them with blinds to prevent direct involvement of sunlight which would speed up the setting of the finish. What we are trying to accomplish is to reduce the speed at which the finish initially sets up. After it has had time to level out, open up some windows to assist is drying.