Polyurethane went bad?

Q: I had my floor professionally sanded, and then I stained it myself, and put a coat of water based poly on. Now the floor looks very dull and chalky. I waited 48 hours for the stain to dry before applying the 2 coats of poly. I did the same thing in another room 6 months ago, and that floor looks fine. I used the same container of poly. Is it possible the poly went bad in those 6 months?

A: I’m not sure. Is it possible when you first used the finish it wasn’t stirred up that much? I ask, because it sounds like now you have a lot of flattener in the finish making it appear matte.

All finishes have a shelf life of about a year. But it is my understanding that out of date generally affects the agents that control anti foaming and flow and not necessarily the integrity of the coating itself. You could try re-coating with Poloplaz 202, a 2 part water borne which has the cross linker built right into the finish so there is no product waste due to short pot life.

Follow-up: Thanks, I think you hit the nail on the head! I just finished applying a 3rd coat of poly out of a new container, and it already looks a million times better.