I have polyurethaned my engineered wood floors many times always using a foam brush and it always turned out pretty well but took a lot of time. The last time I did it I tried a new method someone suggested to me by using a foam roller. This person told me it might show bubbles when I do it but not to worry the polyurethane would settle and dry smooth. Well I was nervous when I seen these bubbles but I stayed the course and let it dry..... BIG MISTAKE. . Now I have a bubbled look on my floors that I can not get rid of. I tried hand sanding with 120 grit paper 5 times and I still see these bubbles so I must not be getting all the way thru the poly coat. So I need any help I can get on how to sand these bubbles away without taking the factory stain with it. I tried a belt sander on extra pieces and found out quickly that will remove the factory finish. Does anyone have any suggestions?

 

Knock that guy in the head that told you that. Foam anything should not be used to poly.
Use a pad like this.
Ettore 10 in. Oil-Based Floor Finish Applicator with Pole-33110 at The Home Depot

Guess your stuck with having have to use a courser grit.

 

Would anybody know if a orbital sander using 220 grit would work without sanding too deep?

 

220 might be too fine to sand out the bubbles. I'd try 150 grit and either go up or down as needed. Don't use a belt sander! An orbital sander will do fine, it just might take awhile.

 

You can test in an inconspicuous area, but I think that once you do an initial sanding and open up all the bubbles, that subsequent coats of poly will blend the defects into the finish.

 

thanks for the suggestions! I will try the orbital sander with 150 grit and go from there. I will let you know how it goes