Water based polyurethane satin gloss looks white and patchy

Q: I sanded my 50 year old hardwood floors and applied stain. The sanding and staining went well. I ran into a problem when I applied the first coat of water based polyurethane satin gloss. There are places where it looks white, patchy.

We discussed this with the stain supplier and they mentioned that we applied the gloss finish on to thick. I have tried to remove the white patches with 80 grit, but this has not solved the problem. I want to apply the next 2 coats. I was wondering how to rectify the problem before I continue.

Reading some of the question and answers.. I see that I have to buff the floor again after the first and second coat of gloss. How do I apply the gloss without having the patches form? How do I get rid of the the white patches that have formed from my first coat?

A: I have used a number of water borne finishes off and on over more than 20 years, but I wouldn’t say I have great experience with them. That is likely to change in the coming days. I haven’t seen your problem, but I have heard of it. I believe it is called blushing. I think it might disappear on it’s own. It is important to apply these finishes in the manner recommended by the manufacturer. That includes spread rate.

Generally ‘snow plowing’ the finish from the furthest wall with a ‘big foot’ applicator is the way to go. You pour a puddle about 4′ out from the wall from one end of the room to the other. You make sure your applicator is wet with finish and then move it down the length of the wall, keeping it on an angle like a snow plow. This will push the puddle away from the wall. You continue this technique until you are at the exit.