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Vob Bila

Will thickened polyurethane get me the same results?

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I noticed my can of polyurethane has thickened some over time, seems to have happened naturally because I always close it when I'm done.

Well it isn't coming out like jello or anything like that, but it is noticeable. 

The fist coat seems to have yielded the same results as a new can would, but thought I'd go to the pros and see what your guy's thoughts were on it.

Any warnings or word of caution jump out in your mind?

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Sounds like a gamble to me.   It must have out-gassed some of the solvents.  I don't like guessing when it comes to finishing-nothing worse than to have to get something off that didn't work out.

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Sounds too risky to me. A new can is so much cheaper than trying to clean up a mess after it doesn't harden. 

Or try thinning it a bit, stir like hell, filter out any lumps then test on scrap. Sand 220 grit after it seems dry and see if it scuffs the surface or gums up the sandpaper. If it gums up then toss the can and get a new one. 

Cleaning the rim of a can and sealing it well prevents some of these issues. Storing in a cool place helps too. Not freezing or roasting in a shed.

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You can thin it back down but mineral spirits alone isn't as good as all the stuff they've got in there to start with that you've lost.  Give it 50% longer to dry between coats than you expect and you should be okay.  There's a limit to how much you can do that so know that you are on borrowed time with that can.

What I do is buy by the gallon and pour the fresh stuff into smaller containers.  I try to always keep the cans at least 3/4s full so there's not so much air in there.  If the can I'm working out of has gotten a little thicker I'll thin it down first and then top it off with fresher stuff.

You can use bloxygen in the can if you know you are going to be storing it for a longer period.

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A little Naphtha might be better than mineral spirits.  Do not use the non volatile eco freindly mineral spirits substitute !

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It has started to cure by polymerization, and will continue getting thicker. Reduce it a bit with mineral spirits so it brushes easily, and use it. It'll cure more quickly on the wood and the stuff left in the can will also continue to thicken and cure, until it's no longer useable.

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