How can I blend sanded cedar into the surrounding darker wood with a polyurethane finish?

Question

I applied unfinished cedar tongue and groove wood, to my ceiling and I applied one coat of minwax fast drying clear polyurethane to it.

I noticed that one of the sections turned a light grey and had streaks from the roller. So I sanded them and accidentally sanded deeper into the cedar wood.
However, since the cedar claims to be unfinished I did not think it would make a difference once I applied a 2nd coat.

Although, as you can see in the picture the light sanding marks are still very visible and make the ceiling look very patchy in that section. What is very strange is that the marks are not as visible if I stand right below it. Any suggestions on how to blend these in?

Answer 1

What grit sand paper did you use? Did you go with the grain? Luckaly you used a very thin product, I would want to resand everything because now that it is sealed and ceilings are not exposed to much direct sunlight & home lighting it probably will look uneven for years. When applying poly a fine sandpaper is used and the idea is not to cut through to the wood. And wipe clean after sanding then a second coat. I would not use a roller with poly because of the increase bubble creation but maybe a fastdrying is ok but I think it would allow less time for bubbles and brush/ roller marks to blend.

Answer 2

Wood naturally changes color over time and it looks like your cedar material was no exception. When you sanded the material in some spots you sanded away the surface of the material that had changed color leaving more of the raw wood exposed. It will be a challenge to try to fix this in any easy way.

Some things you could try:

1. Do nothing and see if over time the sanded areas naturally darken.
2. Cut out the worst boards and replace with new ones. You would have to carefully refinish those areas to get an even look.
3. Look at using a tinted version of the Minwax product to add some additional finish in those areas.
4. Sand the whole ceiling to a consistent look and re-finish. Although this could problematic due to having applied the second coat already so sanding would have to be pretty aggressive.