"dry spots" in polyurethane finish on oak


  #1  
Old 07-04-05, 05:44 PM
bubbajones
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"dry spots" in polyurethane finish on oak

I'm refinishing an old oak table top. I sanded off the old finish and cleaned the surface with paint thinner and then applyed several coats of fast-drying high-gloss clear polyurethane finish to try and achieve the "glass" like coating. Three coats and between each coat I sanded with 220 paper and cleaned off the dust with a rag that had some paint thinner on it.

What's happened is that most of the table is smooth like glass, but in some places the wood looks like it's "soaking" in the polyurethane or preventing the polyurethane to adhere to the surface and leaving patches of dull finish.

Did the paint thinner penetrate the wood and prevent the polyurethane from drying properly or what? Thanks for your help.
 
  #2  
Old 07-05-05, 07:36 AM
M
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Welcome to the forum

I doubt the paint thinner affected the finish [it evaporates quickly] Sounds like you have done everything right. For whatever reason portions of the wood is soaking up the finish. More coats of poly will fix it. You may want to just coat the dull areas until you get them sealed good and then sand and recoat the entire top.
 
  #3  
Old 07-07-05, 12:54 PM
RainieL
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sorry hit enter
 

Last edited by RainieL; 07-07-05 at 01:02 PM. Reason: hit enter too soon
  #4  
Old 07-07-05, 12:59 PM
RainieL
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Does your can of polyurethane say to sand between EACH coat? Most poly's instruct you to sand only after the first coat. I am sure once you have a few coats on you may finally get a build up of poly on that surface. You may have a hard spot. Oak can sometimes have those very hard spots that do not even absorb stain. HOWEVER, a fresh sanding helps to open the grain as well as a few good coats of poly. You may be sanding it all off.
Just some thoughts.
Good Luck
Rainie
 
  #5  
Old 07-07-05, 01:12 PM
M
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Check the label. Most polyurathanes require sanding if not recoated within a certain time frame.
 
  #6  
Old 07-10-05, 02:12 AM
K
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Originally Posted by bubbajones
oak... in some places the wood looks like it's "soaking" in the polyurethane
I think it's as simple as that. Oak is a very porous wood; most tabletops will have bands or patches of straw-like grains opening to the surface which really do drink stain and varnish.

Needs more coats. Also note the poly will continue shrinking - and settling into the grain - for weeks, so plan for another coat or two later.
 
 

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