# Dull Polyurethane



## Nick W. (Jan 30, 2018)

I will try to explain this the best I can because I forgot to take pics. I have a one gallon can of Minwax satin finish polyurethane that I bought and I'm using on four tables that I'm working on. The tables are all being polyurethaned at the same time. The first two coats seemed to be a little glossy than I've had before with this satin finish. My third and final coat that I was adding to the top is suddenly much more of a dull finish than the first two coats. This final (third)coat has small streaks of the more glossy finish on it. This final coat seems to be the finish that the first two coats should have been or is expected with a satin finish. I did notice that before the third coat when I opened the can it had a film over the polyurethane in the can that I pulled off the top of the polyurethane. The tops were sanded between coats like I always have. The tops were dried well before I added a coat of polyurethane. The polyurethane dried 24-48 hours or longer in 90 degree weather and humidity of about 50%. Why is the polyurethane more dull suddenly about halfway through the can?


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## Steve Neul (Sep 2, 2011)

Pictures not needed. What you have to understand about any finish other than gloss is when it's made they put a flattening agent in the finish. In dry form it looks like baby powder and the more of it that is added to a finish the flatter the finish gets and satin has a lot. What happened with your can is it sat on a store shelf long enough the flattening agent made a thick paste on the bottom of the can. You didn't stir it enough when you first started using it so the longer you used it the more concentrated with flattening agent the finish got. You could tinker with the finish you have left and stir in some gloss polyurethane into the finish you have. You just wouldn't know how much to add to achieve the look you want though. It might be easier to throw away what is left and buy another can. If you are not going straight home and use it you could have the paint store put it on a shaker to loosen up the flattening agent on the bottom. As long as it sat overnight before you stirred it there shouldn't be any bubbles in it from having been shook.


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## Nick W. (Jan 30, 2018)

Thanks, I had planned on just buying another can hope that works!


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## Jim Frye (Aug 24, 2016)

These types of finishes not only need to be thoroughly stirred prior to use, but also while applying. On something large like a table top, the flattening agents can settle enough during an application that the sheen will be different from start to finish.


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## Steve Neul (Sep 2, 2011)

Nick W. said:


> Thanks, I had planned on just buying another can hope that works!


Another note on the subject. When working with satin finishes if you apply several coats the finish can get a little cloudy because of multiple layers of flattening agent. The finish would be clearer if you would finish with a gloss finish and when you get to the last coat then use the satin finish. A gloss finish is chemically the same but it doesn't have any flattening agents in it.


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