July 27, 2011

10 Tips for Applying Polyurethane

I've had a couple of questions on this one, so I thought it warented repeating, and placing it in it's own blog post so that we can easily reference it.  So here it is, after much trial and error, my top 10 tips for applying poly to a wood project.
  
1. Stir the can, don’t shake it.  And don't just stir, scoop and pull up the poly from the bottom of the can to the top, which will make sure that the additives that make the poly matte or gloss mix evenly throughout the can.

2. Use a matte finish on beautiful stained wood project, but painted or india ink pieces call for a semi-gloss (or high gloss if you are feeling sassy) to give the finish more depth and interest.

3. Use a water based poly because it washes with water, doesn't have the yellowing effect of an oil base, and you can use it inside so you don't have to worry about bugs or particles in the outside air sticking to your piece.   

4. Apply thin, even coats, but not too thin.  Too thin can leave brush strokes on your project, so apply for a smooth, even finish.

5. Make sure your piece is 100% how you want it before you apply poly.  You can't touch up any stain or paint underneath once it's applied, and poly only makes a mistake look worse.

6. Do not go back over poly after it has been applied, even just 30 seconds later.  Once poly begins to dry, rubbing a wet brush back over that surface will cause brush stokes. 

7. Apply the poly with the grain and the full length of your board/piece.  If you stop or start applying anywhere in the middle of the board you will regret it. 

8. Try to apply in an environment that is above 40 degrees, or below 80.  Do not be an dummy like me and apply when it is 91 degrees and incredibly humid outside.  The poly begins to dry so fast that it’s really tough to make sure you don’t have any brush marks.

9. Unlike staining, I never recommend flipping your piece upside down to poly the underside.  Poly can drip, and there is nothing worse than flipping over your project to discover ugly thick drips on the most visable portion of your piece.  It may take a little yoga positioning to get in the tricky spots underneath, but it’s totally worth it for a clean finish on top.

10. Sand your full piece lightly with between coat sandpaper (220 grit or higher) really lightly before applying a second coat.  This is not just to remove any specs or dust from the first coat, but because poly doesn’t stick very well to itself, and roughing up the edges helps it adhere better.  This will help you avoid any pealing or scratching down the road.  And don’t worry, sanding will cloud up your finish, but I promise it will turn crystal clean again once you apply the next coat. 

6 comments:

  1. Thanks for the input. Point number 6. I'm guilty of doing in the past, so now I know NOT to do it.

    My project is to poly a double door front of a business that gets many visits. Just want to do it right. I was looking for an answer to whether humidity has an effect on the outcome and or applying poly knowing that in about 4-5 hrs after application there may be rain coming.

    Sounds like I should just wait for a dry day in the 70's.....period!.

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  2. Putting 4th coat if poly on painted surface and if gies on thick and covered in bubbles...looking horrible!! Tried brushing with mineral spirits to thin out...helped only slightly... Then tried to remove top coat by scrubbing... Got a little too deep and got past paint and down to primer...can we touch up paint with spray and then spray poly?? Looks terrible....

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  3. Putting 4th coat if poly on painted surface and if gies on thick and covered in bubbles...looking horrible!! Tried brushing with mineral spirits to thin out...helped only slightly... Then tried to remove top coat by scrubbing... Got a little too deep and got past paint and down to primer...can we touch up paint with spray and then spray poly?? Looks terrible....

    ReplyDelete
  4. Thank you for sharing this interesting and informative article, painting with airless spray gun will be faster and more interesting!

    ReplyDelete