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Finishing wood slabs with 16% moisture, can I do it?

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Forum topic by Toomanyprojects posted 11-14-2017 01:35 AM 1859 views 0 times favorited 16 replies Add to Favorites Watch
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Toomanyprojects

6 posts in 7 days


11-14-2017 01:35 AM

Topic tags/keywords: moisture finishing counter top slab doug fir

Hello! I just got 3”Thick slabs that are 7’ long and 24” wide a piece. I am planning on using them to make my counter tops. The thing is, is they are still at 16% moisture. I am planning on installing metal braces on the underside to control warping. I was also told that I could seal the top and sides with a polyurethane while leaving the underside unfinished so that it can release moisture through the bottom. Is all of this going to work? Counter tops would be awfully wonderful as they are the first step to me having a kitchen and not just a grill outside, but I don’t want to ruin my beautiful wood and have to redo everything. Thanks for your wisdom!


16 replies so far

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a1Jim

116497 posts in 3390 days


#1 posted 11-14-2017 01:50 AM

Welcome to Ljs
By using wood that wet your asking for trouble because it’s still drying whether you finish it or not, Putting metal straps on the bottom which will cause your wood to crack because you will have wood movement and if it’s restricted the wood cracks. Do some online research about wood movement to give yourself a better idea of what you’re dealing with.

https://www.canadianwoodworking.com/tipstechniques/dealing-wood-movement

your idea of not finishing the bottom makes it so one side of the wood takes on more moisture the other ,straps or no straps its more lightly to cup. You want the wood to have the same amount of wood exposure finish one side then finish the other.

-- http://artisticwoodstudio.com Custom furniture

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sawdustdad

289 posts in 698 days


#2 posted 11-14-2017 02:33 AM

You don’t mention the species or how the lumber was milled—is it flat, rift or quarter sawn? What species?

Knowing this will give you some idea of what to expect as far as wood movement as the wood dries. Quarter sawn will not shrink as much but if it includes the pith, it will likely check down the middle. If it’s flat sawn, it’s more likely to cup. Some species shrink more while drying than others.

I think if I absolutely needed to use this wet lumber to build counter tops, I would install it temporarily and let it dry in place, without any finish, with the plan to remove and mill it flat for a final install a couple years later. Or, just use some plywood until the lumber dries. Which, depending on how it’s stored and your particular climate might take a couple/three/four years.

-- Murphy's Carpentry Corollary #3: Half of all boards cut to a specific length will be too short.

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Toomanyprojects

6 posts in 7 days


#3 posted 11-14-2017 02:37 AM

It’s Doug fir, I don’t know what flat or quarter sawn means! I live in a dry climate, in 10 days the slabs came down 10% in moisture content

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a1Jim

116497 posts in 3390 days


#4 posted 11-14-2017 03:19 AM

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a1Jim

116497 posts in 3390 days


#5 posted 11-14-2017 03:22 AM

Now it may be safe to use and finish @ 10% ,8% is preferred but will still move some even in a dry climate.

-- http://artisticwoodstudio.com Custom furniture

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AlaskaGuy

3536 posts in 2122 days


#6 posted 11-14-2017 03:43 AM



It s Doug fir, I don t know what flat or quarter sawn means! I live in a dry climate, in 10 days the slabs came down 10% in moisture content

- Toomanyprojects

How are you measuring the MC?

-- Alaskan's for Global warming!

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Lazyman

1425 posts in 1200 days


#7 posted 11-14-2017 05:30 AM



It s Doug fir, I don t know what flat or quarter sawn means! I live in a dry climate, in 10 days the slabs came down 10% in moisture content

- Toomanyprojects

It’s very unlikely that a 3” thick board went from 16 to 10% in just 10 days. More than likely, it just the surface that has dried and not the entire thickness. That may takes months. If you are using a 2 pin moisture meter, you are really just measuring the surface moisture. You can test that by shaving some wood off the surface and testing it again.

-- Nathan, TX -- Hire the lazy man. He may not do as much work but that's because he will find a better way.

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Toomanyprojects

6 posts in 7 days


#8 posted 11-14-2017 02:00 PM

Thanks for all the advice! What do you all think of finishing just the top and leaving the bottom to shed moisture?

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BurlyBob

4949 posts in 2078 days


#9 posted 11-14-2017 02:11 PM

What Jim said! Guaranteed they are going to cup, warp and twist..

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johnstoneb

2575 posts in 1986 days


#10 posted 11-14-2017 02:14 PM

You have a 3” slab 24” wide it is probably flatsawn, it will probably cup as it is drying. By finishing one side and not the other you increased the chances and the severity of the cupping. Finish does not stop moisture transfer it just slows it down. You need to go back and actually read and comprehend and heed the advice given above. and stack and sticker those slabs for 6 month to a year at the very least.

-- Bruce, Boise, ID

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bondogaposis

4432 posts in 2164 days


#11 posted 11-14-2017 02:18 PM



Thanks for all the advice! What do you all think of finishing just the top and leaving the bottom to shed moisture?

- Toomanyprojects


That will almost guarantee cupping. You want wood to dry evenly on all sides. Your lumber is not ready to use.

-- Bondo Gaposis

View bbasiaga's profile

bbasiaga

991 posts in 1808 days


#12 posted 11-14-2017 02:32 PM

Perhaps you can find someone with a kiln nearby that could dry them proper for you?

Brian

-- Part of engineering is to know when to put your calculator down and pick up your tools.

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Toomanyprojects

6 posts in 7 days


#13 posted 11-14-2017 04:56 PM

Thanks Brian! That is helpful advice!

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jonah

1377 posts in 3112 days


#14 posted 11-14-2017 05:23 PM

You can’t “control warping”. If you attach metal to the slabs, they’ll simply bend the metal or crack (or a combination of both).

Wood is extremely powerful as it moves.

Get the slabs dried in a kiln or stack/sticker them for a year or so. With such thick slabs, they’ll need a lot of time to come down to ~8% moisture content.

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Toomanyprojects

6 posts in 7 days


#15 posted 11-14-2017 05:27 PM

Thanks for all the wisdom! Now I know that working with wet wood is a no go. I found a place with a kiln that will dry the slabs for $60 a slab and will take 4 months, better than taking 3 years I think!

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