Water trapped under polyurethane coat!

Discussion in 'Walls and Ceilings' started by jhn.nguyen, Aug 16, 2009.

  1. Aug 16, 2009 #1

    jhn.nguyen

    jhn.nguyen

    jhn.nguyen

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    My family and I recently decided to sand, stain and polyurethane my entire upstairs floor. We let the stain stand and dry for a week before applying the polyurethane so that can't be the problem. However before using the applicator for the poly, it was recommended that it be rinsed with water. The applicator may have still been wet during application and now cloudy spots are seen all over the floor after the first coat. How would we fix this without stripping?

    Any help is appreciated, thanks alot.
     
  2. Aug 16, 2009 #2

    Nestor_Kelebay

    Nestor_Kelebay

    Nestor_Kelebay

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    Was this a water based polyurethane you were applying, or an oil based polyurethane?

    The applicator should only be soaked with water and then squeezed out when applying water based polyurethane. And, yes, it SHOULD be damp to the touch when you start using it to spread your WATER BASED polyurethane.

    Can you look on the container of the poly you applied and find out what kind of poly it is?

    If it's water based poly that you applied, then what you have are microscopically small droplets of water formed within the poly. Basically, the white discolouration you're seeing is the reflection and refraction of light at the water/solidpoly phase boundaries within the polyurethane. Take a hair dryer to heat one area of polyurethane where the discolouration is worst. The heat will drive the liquid water into H2O molecules which will disperse in the polyurethane. Once you drive all the liquid water into H2O molecules in the area, the white discolouration in that area should disappear as the water/solidpoly phase boundaries within the poly disappear.

    Basically, what you're seeing is quite literally a "cloud" inside your polyurethane.
     
    Last edited: Aug 16, 2009

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