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I applied my first coat of General Finishes water based poly last night. But now after sanding with a 3M finishing pad, I am seeing blueish fogginess on the table top. It doesn't seem to be dust, since I can't wipe it off.

Will this go away in the next coat? If not, how do I fix this? Thanks in advance

To prep this top, I first sanded to 220 grit. Also, I applied two coats of Old Masters. Tung Oil Varnish

The blueish gray bits are visible on the left side of the image.

Table

Matt
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wizurd
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  • Thanks for the picture. What did you do to prep the piece before you finished it? The latter is more important to a better solution. Hard to see from the angle. Does that discoloration show on the whole table top – Matt Oct 01 '15 at 01:53
  • @Matt. See update – wizurd Oct 01 '15 at 01:56
  • Discoloration is only on parts I sanded – wizurd Oct 01 '15 at 01:57
  • This might be related. http://woodworking.stackexchange.com/questions/2068/can-i-apply-water-based-polyurethane-over-an-oil-based-stain – Matt Oct 01 '15 at 02:11
  • I think I'm ok on that front. It had been > 36hrs since my final Tung Oil Varnish application before I applied the first coat of poly. And, there was no "beading" when applying the poly. Hopefully this will just go away with the second coat... – wizurd Oct 01 '15 at 02:32
  • I don't think this really warrants a formal Answer so I'll just leave a Comment instead. "Will this go away in the next coat?" You can preview the effect by just wiping with a damp cloth. If the greyish look goes away you'll likely be fine. If it doesn't however then the effect may be in the finish and not a surface defect. – Graphus Oct 01 '15 at 10:52
  • Hey did that bluish grey tint ever go away? I’m in that same situation now. I just applied one thin coat on finish and once I sanded it. I was left with the same result. I’m working if that 2nd cost fixed the issue for you? – Mohammed Chowdhury Nov 09 '19 at 16:52

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From the picture, it appears to be the open grain of the wood. This is typical in an initial coat because if you have done it right, it will be relatively thin. A good way to tell, is if you can lightly feel a difference in the finish where the spots are in comparison to the rest of the top. If it looks like this is the case, you should notice it disappear in the next coat.

  • If not, try to determine whether it's in the finish or on the surface. Poly can be a fragile process because it takes so long to cure and needs a virtually dust-free environment. If it appears to be on the surface, you should be able to sand it out of the finish. If your scotch pad isn't enough, a piece of 220 or higher should be fine so long as you're careful not to go too deep. Also, if using sandpaper, be mindful of uneven scratching in the finish. It will add an extra coat or two to your process.

  • If it appears to be in/under the finish, I'm afraid the only way to save it that I'm familiar with is the old fashioned way; sand/strip the finish off and start over.

I hope this was of some help. Another tip in finish work; one of the most common mistakes when scuffing between coats is to overdo it. Scuffing is only meant to smooth the surface for the next coat so it usually doesn't take much. Best of luck to you.

WoodButcher
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