Uneven finish (some sizable portions not properly taking finish)

[Frank Martin]

This is a walnut coffee table top. Finish so far is couple coats of poly applied with a foam brush and after each coat I scrubbed it with scotch brite (maroon). Immediately after applying the finish, it all looks even. But after drying some portions look as if they did not absorb finish properly and also feel rough. Attached are couple pictures showing the problem areas. See about center of each picture.

Any suggestions on how to proceed?
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[Rich Engelhardt]

Yeah - sometimes pine, birch, cherry and walnut do that. Just keep putting on coats until it stops.

A coat of dewaxed shellac prior to the finish coat (even now after a couple of coats) will also help seal those "thirsty" spots.

[Frank Martin]

Yeah - sometimes pine, birch, cherry and walnut do that. Just keep putting on coats until it stops.

A coat of dewaxed shellac prior to the finish coat (even now after a couple of coats) will also help seal those "thirsty" spots.

Okay, will try the shellac as I don't really want to pile on more coats of poly. In fact I have a highly valuable quart of Waterlox (I live in CA and it is no longer sold here) that I may use for the final coat as I will be putting on a coat of shellac first. I always liked Waterlox….

[Rich Engelhardt]

Just be sure to use dewaxed shellac.

Zinsser Seal Coat is a good pre mixed dewaxed shellac.

[Kent A Bathurst]

Yeah - sometimes pine, birch, cherry and walnut do that. Just keep putting on coats until it stops.

A coat of dewaxed shellac prior to the finish coat (even now after a couple of coats) will also help seal those "thirsty" spots.

Bingo. The wood is reversing grain throughout the offending parts - looks to me like your problem areas are the equivalent of end grain - right in the middle of flat/long grain. Varnish is being absorbed at different rates. Dadgum trees simply refuse to cooperate. ;)

Personally - I always put down 1 - 2 seal coats of !! 1# cut dewaxed shellac as my very first step. Sometimes may not be needed, but never hurts, and the end results are more predictable.

Rich hit the 10-ring on his answer - pretty typical for him.

[Rich Engelhardt]

Jim Becker's finishing regime calls for a coat of BLO first to "pop" the grain, followed by a coat of dewaxed shellac.
He's mentioned a few times that he uses that on just about everything & that walnut is his favorite wood.

I've never thought of it before, but, I wonder if the BLO itself doesn't help fill up those "thirsty" spots?

That's something to mull about over the Winter.

[John TenEyck]

I wonder if the BLO itself doesn't help fill up those "thirsty" spots?


More likely the shellac.

John

[Frank Martin]

I did put a coat of dewaxed shellac and still have quite a bit of uneven finish. I guess I need to keep feeding those thirsty spots until I see even sheen. You guys are definitely right though, all those spots have reversing grain. Thanks for the help.

[Frank Martin]

Okay, I applied couple coats of dewaxed shellac and poly on top which addressed the uneven absorption problem. However, I still don't like the top coat as the poly did not flow out well. Eventually, I would like to get to high gloss, smooth surface. I am thinking of two options:

1- Scuff sand and apply poly by diluting about 1/3 using mineral spirits. I am not sure if diluted poly will flow better or would I need to do final polishing. Never polished poly before, and if I recall correctly, it does not polish well. If it matters, poly I am using is Varathane from the big box store...

2- Sand back the last layer of poly and apply Waterlox. In the past Waterlox got me there without final polishing. My thought is, I can just do a last coat or two Waterlox and not worry about final polishing. However, not sure if I would have adhesion issues. Should I apply another coat of dewed shellac or not worry about it.

What do you recommend?

As a side note, I plan to go back to spraying waterborne, but this time with Target Coatings products as I had trouble with General Endurovar. Oil based is too much work...