Minwax Gloss Poly over Seal Coat

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Forum topic by wseand posted 02-20-2012 07:57 PM 2415 views 0 times favorited 8 replies Add to Favorites Watch
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2796 posts in 3005 days

02-20-2012 07:57 PM

Topic tags/keywords: question oak finishing zinsser seal coat minwax polyurethane

I am finishing a Red Oak table and having a heck of a time with the finish. I put two coats of Zinsser Seal Coat on and then sanded to 320. It seemed to be good.

I waited a few days to put the poly on, just because. I put a coat of the Poly on and it seemed to raise the grain a bit. I wasn’t to worried about it because I figured a light sanding after each coat would fix it. Well after the third coat it really raised the grain and I was stuck with what felt like the Cascade mountain range.

I have since sanded it down to nearly bare wood. Any suggestions on what to do next or name calling for screwing it up would be appreciated.

The RO was Rough FAS and I let it acclimate for about a week and a half then milled it.

8 replies so far

View Lee Barker's profile

Lee Barker

2170 posts in 2814 days

#1 posted 02-20-2012 08:06 PM

I don’t have a quick answer, Bill, but I suspect the accumulated wisdom here will help you out.

When I think of raised grain, I think of roughness caused by small hairlike fibers of the wood popping off the surface due to the addition of some kind of liquid.

My first question is, how did you clean the wood after sanding the SealCoat? Could that residue be what is showing up on the surface?

Is “Cascade Mountain Range” hyperbole, or is the surface really that bad? Maybe you could describe the surface in more detail for us.

Over the net to your court…



-- " his brain, which is as dry as the remainder biscuit after a voyage, he hath strange places cramm'd with observation, the which he vents in mangled forms." --Shakespeare, "As You Like It"

View Tennessee's profile


2860 posts in 2478 days

#2 posted 02-20-2012 08:14 PM

The only thing that comes to my mind is your moisture content is too high in the wood. Now that you are sanding it down to almost bare wood, I’d leave it a couple days and see if you get some grain raise. That would be a sure sign the surface of the wood is still drying as alternate grain patterns should rise a little as it dries.
The other reason I say this, the poly would not penetrate the higher moisture areas as much, since the pores are filled with moisture, so when you sanded, you got your “mountain ranges”, which I bet sort of follow the grain. Need to lower the moisture percentage is my bet.

-- Tsunami Guitars and Custom Woodworking, Cleveland, TN

View wseand's profile


2796 posts in 3005 days

#3 posted 02-20-2012 09:33 PM

It was quite rough, it felt like little hills and valleys. Mostly where the grain was smooth to where it was more porous. I would say the porous areas were the valleys and the smooth parts were the hills.
I normally blow off the dust than wipe it with mineral spirits I could have missed that step but pretty sure I didn’t.

I guess I didn’t think of the moisture content really due to the fact that I got the wood close by and I didn’t think it would make much of a difference. I have never run into this problem before. But I rarely use Oak, don’t like it much. Now that I look closer at the wood I see some black spots showing up in the pours of the grain, maybe some mold. Our Humidity in the area fluctuates between about 15% to 70% throughout the day. I might just be fighting a losing battle here. I will have to invest in a Moisture meter, I had one some time back but it broke.

I am going sand it down to the wood and let it sit til I can get a meter. I don’t plan on using the sanding sealer again, maybe some oil then the poly. I just wasn’t sure if the sealer than the poly could have caused me some issues,

Thank you both for your replies.

View Clint Searl's profile

Clint Searl

1533 posts in 2325 days

#4 posted 02-21-2012 12:08 AM

1. Get back to bare wood by stripping or sanding.
2. Sand to 180.
3. Apply a coat of waterborne floor poly (preferably Varathane)
4. Knock down any fuzz with 220 drywall sanding screen
5. Apply two or three full wet coats with intermediate sanding with maroon Scotchbrite
6. Rub out the top coat with auto polishing compound

-- Clint Searl....Ya can no more do what ya don't know how than ya can git back from where ya ain't been

View wseand's profile


2796 posts in 3005 days

#5 posted 02-21-2012 12:33 AM

I wil give it a try. Sounds like a good idea. Thanks for the input.

View BruceJ's profile


1 post in 2241 days

#6 posted 03-01-2012 03:09 PM

Bill – You have received alot of great tips, so mine will sound somewhat repetitive. The phrase “The smoother the wood, the smoother the finish” rings true. Dust left in the pores can also lead to a rough finish. Grain raising caused by a water-based stain or finish can be reduced by first applying a coat of Wood Conditioner to the bare wood, letting it dry, then sanding off the ‘fuzz.’ Any minor grain raising caused by the water-based finish can be eliminated by sanding between coats with #220-grit sandpaper, then wet-sanding the last coat with #600-grit dipped in lemon oil. I hope this helps. – Bruce Johnson (Minwax spokesperson)

View Bill White's profile

Bill White

4901 posts in 3924 days

#7 posted 03-01-2012 04:44 PM

I can’t imagine that Seal Coat was a problem, but then….......


View wseand's profile


2796 posts in 3005 days

#8 posted 03-02-2012 05:10 PM

Thanks all for your input. I ended up sanding it to bare wood and then wiped down with mineral spirits. After that I wiped with a wet towel to raise as much of the grain as possible. I let it dry and than sanded to 800 grit. I then cleaned with mineral spirits again and put four coats of water based Poly on. Used a little turtle wax polishing compound and it came out great. Sorry, but not the best picture.

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