What to thin poly with???????

Al killian

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Floydada, Tx
I just bought a spray system and while does a good job a spraying lacquer and stains, it doesnt do good at spraying thick oil based poly. So what works best for thinning it? On hand I have, mineral spirts, DA, Lacquer thinner and Aceatone. Or do I need to buy something different?
 
From Fine Woodworking (for wipe on):

Use mineral spirits to thin oil-based polyurethane
by 20% to 30%

I would assume a bit more for spraying but MS seems to be the recommended thinner. They also, oddly enough, voted Minwax wipe-on poly as the easiest to use with the best outcome. I say 'oddly enough' because I hear so many folks complain about Minwax(?).
 
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I agree with Glenn's response but I have a question myself.

When I thin polyurethane with mineral spirits and store it in an air tight container in just a few days it will gel. Is that because I have incorporated too much air into the mix while stirring in the MS or some other reason?

I still use a poly/oil/MS home brew on occasion and learned that I cannot make much more than I plan to use as it will almost certainly gel in a few days.
 
OK, I will give it a go. Like Mike I also have noticed that that when I rinse my brushes that had poly on them in ms it turns to a white colored gel.
 
read the can.......most manufacturers give thinning or clean-up instructions.
often the "thinner" is listed as a "cleaner" because we all know that thinning finishes causes cancer in california rats and pregnant penguins.;)
 
Tod, it says to clean with either paint thinner or minerail spirits. I thinned it 1 part ms to 2 parts poly. It laid nice and smooth and dried in enough to recoat in 2 hours.
 
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