# Polyurethane air bubbles



## lhaas05 (Jul 10, 2011)

I am refinishing the top of my cherry dresser. I have done other projects and this is the first time I am having problems with air bubbles (and I mean a lot of bubbles!). In the past I had problems with brush strokes, but have learned to apply more polyurethane to eliminate that problem. I have an expensive china brush and have a good quality of polyurethane (Old Masters). I am going over the poly with a very light stroke, but bubbles do not go away. I sanded after the first coat to get rid of air bubbles, but on second coat I have even more! What to do?


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## jlord (Nov 16, 2009)

There is no direct sunlight on your project is there?


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## del schisler (Feb 2, 2006)

lhaas05 said:


> I am refinishing the top of my cherry dresser. I have done other projects and this is the first time I am having problems with air bubbles (and I mean a lot of bubbles!). In the past I had problems with brush strokes, but have learned to apply more polyurethane to eliminate that problem. I have an expensive china brush and have a good quality of polyurethane (Old Masters). I am going over the poly with a very light stroke, but bubbles do not go away. I sanded after the first coat to get rid of air bubbles, but on second coat I have even more! What to do?


Did you get all of the old finish off?? Down to the bare wood. If not that would be your answare. The dreaser was nost likely sprayes with lacquer? Sound like you are going to have to remove all the finish you have put on already and get it down to the bare wood. Check back


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## bobj3 (Jan 17, 2006)

2nd. del post

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del schisler said:


> Did you get all of the old finish off?? Down to the bare wood. If not that would be your answare. The dreaser was nost likely sprayes with lacquer? Sound like you are going to have to remove all the finish you have put on already and get it down to the bare wood. Check back


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## xplorx4 (Dec 1, 2008)

Greetings Del and welcome to the router forums, we are glad to have you join us.


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## Mike (Nov 22, 2004)

Laurie, I always use Purdy brand brushes for finishing. When everything else is right these brushes get the best results I have seen; Purdy brushes are highly recommended by Michael Dresdner. (Michael is the finishing expert for The Woodworkers Journal)


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## Phil P (Jul 25, 2010)

+1 on Purdy brushes here


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## bobswodshop (Aug 20, 2011)

I have had luck with putting first coat on with QUALITY brush, sanding then putting final coat/coats on with a quality foam brush. not the free after rebate ones. Very seldom have a bubble. Brushing tecnique also makes a difference. Just something to try.


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## OPG3 (Jan 9, 2011)

Several years ago, I made a custom table for someone's business work area. Dimensions had to be exact due some equipment compatibility and fit issues. It also had to be very heavy-duty, yet look elegant to match adjacent furniture. I make no claims to doing beautiful work, but this one needed to look really nice. Long story short, I commented to my wife about my ongoing project and mentioned *this exact problem* with polyurethane bubbles. She proceeded to tell me how "Norm" had solved this problem on the Yankee Workshop TV Show. I took a small hand-held propane torch with a "flat-funnel flame spreader" and simply passed it over each successive coat - the bubbles diminished immediately when swiped by the flame. I just wish I had mentioned it to her earlier. I think Norm learned it from David Copperfield! *OPG3*


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## Cherryville Chuck (Sep 28, 2010)

[Q I took a small hand-held propane torch with a "flat-funnel flame spreader" and simply passed it over each successive coat - the bubbles diminished immediately when swiped by the flame. I just wish I had mentioned it to her earlier. I think Norm learned it from David Copperfield! *OPG3*[/QUOTE]

Similar to Otis' suggestion, I have had some luck using a hair dryer on same issue. Thinning the poly might help too. It seemed to me that the thinner the poly the better the hair dryer worked.


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## AxlMyk (Jun 13, 2006)

I thin the poly with mineral spirits first. Goes on much smoother.


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## jlord (Nov 16, 2009)

No mention whether it was a water base or oil base poly he was using. He must have solved the problem he posted this July 9


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## AxlMyk (Jun 13, 2006)

I also noticed the date. At least it wasn't started 3 years ago.


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## jlord (Nov 16, 2009)

There seems to be a lot of that lately.


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## OPG3 (Jan 9, 2011)

Hey friends, here is another tidbit from my wife (her memory is better than mine): DO NOT SHAKE polyurethane, but rather stir it very gently. Shaking it introduces additional bubbles - which make the chore more difficult than before. Another tip - the torch flame must be moving at an appropriate pace: too fast hardly helps and too slow makes your project catch fire! I apologize, but this aging process takes its toll on me... *OPG3*


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## dougj71 (Feb 17, 2008)

Bob Flexner says that shaking does not cause bubbles.


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## papawd (Jan 5, 2011)

I have been cheating lately and using spray on poly,just spray with light coats and allow ample time to dry between coats my last 5 gameboards I have done this way and it only takes a few minutes to spray instead of alot of time brushing .... just my 2 cents


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## OPG3 (Jan 9, 2011)

Doug,
You may be correct about Bob Flexner's comments, however; 
1. The can says to stir not shake.
2. I went to Applying Polyurethane - Woodworking Finishing Tips - Tips for Applying Polyurethane for a Perfect Finish - You may find that interesting.
3. Bob wasn't there when my wife suggested this.
Thanks for your comments, *OPG3*


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