# Polyurethane yellowing



## radeere (Jul 3, 2012)

I make cornhole boards and lately have been making alot of them. I've been using a water based 'polycrilic' by minwax and have achieved good finishing results. However, I've gotten some complaints that the finish isn't durable enough. For my last set of boards I used a spray can of polyurethane by Minwax and found that it caused yellowing in the white paint. Not sure what to try now. I want the more durable finish, but I also want the paint to be bright white. The lady at home depot suggested clear spray paint. Any suggestions?


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## Dave Paine (May 30, 2012)

The water based finishes are likely to not be as durable as the oil based.

The oil based finished I have used all have a yellow/amber cast to them. I expect your Minwax spray was oil based.

Even on bare wood, you will see some yellow/amber cast. I happen to like this.

You could look at the Enduro-Var line from General Finishes. Water based, but may be more durable.

http://www.woodcraft.com/Family/2081078/EnduroVar-by-General-Finishes.aspx

Otherwise you may end up with clear coat.

I read on some other message board that a good clear exterior finish is latex paint - but WITHOUT any pigment added. Go to a big box store and ask for them to give you just the paint - no additives.


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## Steve Neul (Sep 2, 2011)

A picture of your project would help. If the board is painted white than I would use an gloss oil based alkyd enamel such as All Surface Enamel from Sherwin Williams and not put any clear coat over it. If part of it is white and part of it is natural wood then I would finish the natural wood area and then mask it off and paint the rest of the board. Kwick Kleen makes a fast dry polyurethane that is non-yellowing however it being fast dry would take some experimenting to see if it would lift paint. Sometimes the solvents in the fast drying products will lift enamels and ruin them.


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## Brian Hinther (Aug 5, 2008)

Re: post #2

Ask for dark paint base (usually #4). It's available in acrylic or oil-based.


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## radeere (Jul 3, 2012)

As you can see, the back set is the one that yellowed. It looked exactly like the front set before I put the polyurethane on it.


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## Steve Neul (Sep 2, 2011)

It's just a bad idea to put a clear coating over white paint. Regardless of how good of a clear coating you use it will eventually cause you some problems.


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## HowardAcheson (Nov 25, 2011)

Using latex paint base is not a good choice for a "clear paint". The paint base to use is an oil based base. The following is an article adapted from a write-up by the guy who first developed and popularized the process.

http://www.hardwoodlumberandmore.co.../75/ArticleId/26/Paint-On-A-Clear-Finish.aspx


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