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Forum topic by donburkard posted 03-06-2014 11:50 PM 1229 views 0 times favorited 15 replies Add to Favorites Watch
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donburkard

22 posts in 1653 days


03-06-2014 11:50 PM

Hey guys, I installed some walnut counter tops for a customer a few weeks ago. She had ordered them from a local Amish wood dealer who I have dealt with before. He does nice work. I picked them up and finished them for her and then did the install. They are black walnut, 1 1/2” thick. I finished them with waterlox. They turned out great but within a week the smallest peice (30”long x24”deep) started to cup real bad. My question is has anyone had this happen and how did you fix it? I had planned on just putting a few cleats across the bottom to pull the middle back down slowly ? Any thoughts? Thanks

-- "Well, sir, it's this rug I have. It really tied the room together." (The Dude)


15 replies so far

View bbc557ci's profile

bbc557ci

589 posts in 1538 days


#1 posted 03-06-2014 11:59 PM

So, the cup you mention is a rise in the center of the top?

-- Bill, central NY...no where near the "big apple"

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HerbC

1592 posts in 2323 days


#2 posted 03-07-2014 12:00 AM

Question: Did you finish both the top and the bottom of the slab?

The piece may not be really dry and could be warping as the slab dries.

I think you’ll find that you can’t really solve the problem with cleats and it may lead to the slab cracking.

Good Luck!

Be Careful!

Herb

-- Herb, Florida - Here's why I close most messages with "Be Careful!" http://lumberjocks.com/HerbC/blog/17090

View joeyinsouthaustin's profile

joeyinsouthaustin

1294 posts in 1536 days


#3 posted 03-07-2014 12:11 AM

Also, is the installation in a way that is causing expansion problems? I also agree with HerbC that equalization may be a problem. Just need some more info.

-- Who is John Galt?

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donburkard

22 posts in 1653 days


#4 posted 03-07-2014 12:15 AM

Bbc557ci- yes

Herbc- I think I did one coat on the bottom.

It’s not a solid slab. I think that piece has 3 or 4 pieces joined together

-- "Well, sir, it's this rug I have. It really tied the room together." (The Dude)

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joeyinsouthaustin

1294 posts in 1536 days


#5 posted 03-07-2014 12:27 AM

Barring it being trapped and expansion being the problem, it could be stress integral to the wood. Since it is a CT added cleats could help. You can also back cut the slab with kerf lines to help release the tension and allow the counter top to be pulled down flat. You can later fill these kerf lines with splines and glue them for stability.

-- Who is John Galt?

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bbc557ci

589 posts in 1538 days


#6 posted 03-07-2014 02:48 AM

I agree with joey post 5. If the top was cupped down in the center, I’d ask if bottom has the same no. of coats as the top.

-- Bill, central NY...no where near the "big apple"

View Rick M's profile

Rick M

7917 posts in 1844 days


#7 posted 03-07-2014 03:25 AM

Whatever you do to one side you should do to the other so equal number of finish coats on each side or you risk cupping especially since one side is exposed to the air. Safest bet is uninstall, see if you can remove the cup then even out the finish coats. If a cleat won’t pull the cup out then you may have to kerf the bottom.

-- http://thewoodknack.blogspot.com/

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oldnovice

5729 posts in 2832 days


#8 posted 03-07-2014 04:12 AM

+1 with Rick!
Finishing requires balance just like veneering.

-- "I never met a board I didn't like!"

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donburkard

22 posts in 1653 days


#9 posted 03-07-2014 04:59 AM

Yea. Thought I could get away with it this time. Haven’t really ran into to much of this problem before. That’s what I get for getting to lax. Thanks everyone

-- "Well, sir, it's this rug I have. It really tied the room together." (The Dude)

View realcowtown_eric's profile

realcowtown_eric

565 posts in 1401 days


#10 posted 03-07-2014 06:32 AM

what them other fellas said. Finish both sides, and if there’s a sink cut out silicone the endgrain too!

Wood countertops is a recipe for call back and warranty replacements!!!

Don’t think the Amish do returns.

Eric

-- Real_cowtown_eric

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basswood

261 posts in 1084 days


#11 posted 03-07-2014 01:44 PM

If the boards are flat sawn and are not glued up with the pith and bark sides alternating, that could cause this problem. If you can see the end grain and the rings in most of the boards are “cup up” (like the right side of this photo) the top will tend to crown as the rings “flatten out”.

I always alternate the ring orientation like this, on flat sawn stock:

-- http://www.basswoodmodular.com/Tri-Horse-Builder-Plans-p/thbp.htm

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basswood

261 posts in 1084 days


#12 posted 03-07-2014 02:00 PM

The photo I posted was too large to fit the frame. Anyone know what pixel width fits best in posts on LJ?

-- http://www.basswoodmodular.com/Tri-Horse-Builder-Plans-p/thbp.htm

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basswood

261 posts in 1084 days


#13 posted 03-07-2014 02:11 PM

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joeyinsouthaustin

1294 posts in 1536 days


#14 posted 03-08-2014 01:29 AM

Sounds like you have a direction, or solved the problem? (post #9) so, to be thorough what solved the problem?

-- Who is John Galt?

View donburkard's profile

donburkard

22 posts in 1653 days


#15 posted 03-09-2014 04:20 AM

I cut some kerfs, started finishing the bottoms and clamped it down to a flat surface to pull it back to flat. I’ll give it a few days, putting a coat of the waterlox on once a day for a few days and see if I still need a cleat in a couple days. Thanks everyone

-- "Well, sir, it's this rug I have. It really tied the room together." (The Dude)

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