I hired a painting contractor to stain and poly my new windows. He used (2) coats of oil based polyurethane, but after the second coat, the finish was rough on the pine sashes. The oak jams and casing were fine. I asked him to come back and sand and apply another coat to the sashes, which he agreed to do. I was home when he began the sanding, but left before he began applying the poly. When I got home, the sashes were smooth, but the sheen was much duller than the oak, which wasn't the case after the first 2 coats. I am suspicious of the application of a third coat, but he was adamant he applied it. The windows were not tacky when I got home as well. He said the lower sheen was the result of the additional sanding, but wouldn't the additional application of the poly have the same sheen, as well as be tacky?
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1There are guys on here that will answer this better than me but all woods have different finish looks and moisture content. You cannot expect two different woods to look the same when going through the same process. As for the tackiness I would give it time and sand with a finishing paper.– DMooreCommented Mar 5, 2014 at 1:38
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In my experience, the sheen should be the same. The appearance would differ because of the two types of wood. I too am suspicious that all that was done was to smooth it with fine sandpaper. But, you may be able to bring back the luster with a wood furniture, or even WD40.– getterdunCommented Mar 5, 2014 at 3:13
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You'll never know. A better question for this Q&A format would be how to increase the sheen of finished wood if that's what you want to have happen.– Keith HoffmanCommented Mar 5, 2014 at 5:58
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Photos of the two finishes would probably help people answer this more accurately.– Bernhard HofmannCommented Mar 6, 2014 at 13:34
2 Answers
I hate to be critical of other contractors, but from the clues you have given in your question, I think I know what happened.
First, pine is a much softer wood than oak and needs to be sanded very smooth before the first coat of urethane. The first coat raises the grain of the pine and almost always is somewhat rough regardless of how good the initial prep was. The first coat is sort of a sealing coat and must be sanded lightly to smooth it for the second coat. If the first coat is not fully cured and sanded, subsequent coats will only exaggerate any flaws or roughness. This is what I think happened when you noticed the roughness.
As for a difference in sheen. If the contractor applied the same urethane, semi-gloss for example, the sheen should be pretty much the same as it was before the 3rd coat. They may have used one grade lower sheen. Satin instead of semi, or semi instead of gloss. If you can see any noticeable unfilled sanding marks or really thin coverage, then perhaps the rough surface was sanded with a very fine paper and not over-coated. Oil based urethane stays tacky for several hours. At best conditions, it could be dry to the touch after 2 to 3 hours.
One possibility is that he sanded the 2nd coat and then applied the third coat without adequately cleaning the sanding dust off. Another possibility is that he used too rough a sanding which would produced a lot of scratches in the coat.
