12 inch wide oak

[Brad_bb]

So I want to use 12 inch white oak flat sawn boards for paneling, circle sawn to be exact.  I know drying flat becomes an issue, but what if I cut them thinner, like 3/4?  Will weight on the stack help keep them in place?  I'm thinking if I saw them thinner, they will be more flexible and maybe weight on the stack will help keep them in place while air drying?  Also being thinner,  their flexibility will allow them to be flattened out when face screwing them in place?

[GeneWengert-WoodDoc]

What size are your logs, as a flat sawn wide piece away from the pith will require at least a 20” diameter log.  Also, what will you do with all the narrower pieces of oak and the pieces closer to the pith that will cup quite a bit and will have many knots, leading to distortion in the area around the knots?  Even if you can hold the pieces somewhat flat at the contact area with the stickers, you cannot hold the wide pieces flat between the stickers.  If you decrease the sticker spacing to 12” instead of 24”, the weight at each sticker is cut in half because there are twice as many stickers.  Less weight means more warp.

Thinner lumber will help, but 3/4” oak is not very thin.

Top weights can help...usually 10” thick of concrete is required to get good benefits.  The warping force is huge, so lots of weight is needed.

Lumber will be flatter if you can avoid rain or melting snow contact.

Now, the humidity in a home does vary from summertime to wintertime.  As a result, flat pieces will move slightly from season to season.  That is, drying does not make pieces stable.  So, you can expect at least 0.1” movement in width.  Screws will not prevent this width shrinkage.  Also, the tendency to cup with these seasonal humidity changes cannot be well controlled with screws...get large enough screws space close together to hold the wood and then the wood will crack.

Bottom line is, unless you want a unsmooth paneled wall (rustic), this is not very likely to be a successful project.

[WDH]

I would saw them thicker, and once they are kiln dried, you can plane them to the finished thickness after flattening one face.  However, you will need a least a 12" jointer. 

[PA_Walnut]

Double-down on the labor and quartersaw them. Of course, won't be as wide, but will be more stable and PRETTY! 

[Don P]

We are planing the barn siding I'm waiting to dry but that will not yield a sawn face. We sawed 5/4 hoping to finish around 7/8", mostly 6 and 12" hoping to use the wide boards on the north road side. We'll break down the severely cupped boards. I'm not at all sure we sawed enough 12" to get enough finished flat, considerable cupping going on at that width. At 6" they have been flatter, crook has been an issue and would be in QS as well. For wide paneling you can maybe kerf the backs to relax the cupping but that might just promote cracks later with seasonal movement. Without reworking it oak is pretty rustic wood.

[moodnacreek]

Above replies are accurate, nothing I could add.

[mike_belben]

At what thickness do flat sawn red and white oaks start to get more stability?  Say in 10 and 12" width.  

[scsmith42]

Brad, I've had some success doing this utilizing a couple of different methods.

Method 1.  Mill to produce a 5/4 dry board (1-3/8" green), fully dry, resaw down the middle and plane to thickness.  The biggest challenge with doing this is getting the board the exact same MC% between core and shell.  If you don't have it close, the boards will cup coming off of the resaw.

Method 2.  Saw at 1", sticker on 12" spacing and weight the stacks with concrete slabs.  I have old concrete sidewalk slabs that I use for this purpose.  After complete drying S2S to desired thickness.

[Brad_bb]

Let me clarify a couple things here.  

1. Danny, I want a circle sawn finish on one side.  So that rules out planing the boards to thickness.  

2. I want the pieces about 12 inches wide.  

3. Thickness is really not critical.  In some places I will need a bit thinner panel to slip behind a timber.  This material will line the walls of the stairwell in my timber framed shop.  

4. I'm planning on cutting 12.5 inch cants on my band saw and then taking those over to the circle sawyer to slice into boards.  I will need to specify thickness to him, which I have yet to determine based on this thread.

An option would be kerfing the back side of the boards?  Anyone done that successfully?  If so how deep and how far apart?

Scott, you're saying rip a 5/4 board into two 2/4 boards?  To do this though, you couldn't have any up in the original board, eh?

PA_Walnut, You'd need some awfully big logs to get 12 inch quarter sawn boards.  That would look awesome.  Mine are probably in the 24-30 inch range.  I don't think I have enough for this task though, so I will have to buy the remainder from the circle sawyer.

[Don P]

This past weekend a friend was saying he kerfed one of our slabs that was cupped and layed it back down. I don't know the particulars but it sounded like he did quite a few and pretty deep. The potential of it splitting concerns me.

When we were building milled log homes the siding was very often not flat on the backside and wouldn't seat well. I wasn't as concerned with the face thickness uniformity as I was with getting the edges to meet well. I imagine this is similar, you can accept some amount of concave cupping of the face as long as the edges meet reasonably well. I would run a few passes with the power planer on the backside of thesiding to create a relief. This would let the siding bear against the sheathing just on the edges rather than rocking and creating ugly joints between boards. With this if you run them through the planer concave face down it would do pretty much the same thing, the edges would be uniform and the faces would be concave to whatever degree is your cutoff tolerance. If the feed pressure flattens them and they spring back then a relief would be one solution. With that method you would then need to think about whether to inset the trim or accept that cupped face degree of gapping.

[Brad_bb]

Thanks.  I might rip  the edges after drying, or I might color the sheathing dark and just butt the edges as well as I can, or maybe leaving a uniform 3/16 gap?

Just an FYI, I'm setting up to do some test pieces ammonia fuming tomorrow. If it works well, I am thinking I'll fume the oak paneling so it looks older.  That is what I'm planning to do to the two interior Q-sawn doors I had built.  More on those later in a separate post.

[scsmith42]

Scott, you're saying rip a 5/4 board into two 2/4 boards?  To do this though, you couldn't have any up in the original board, eh?

Brad, it seems as if thin lumber (<3/4") tends to distort more in the drying process than thicker lumber, unless it is stickered very close and weighted.  So the advantage of milling 5/4 and then resawing is that the boards tend to stay flatter while drying; albeit at a cost of a longer drying process.
I've successfully dried 3/4" green boards, but with close stickering and heavy weights on top.  

[Brad_bb]

I'm taking your point in Scott.  Mill thick enough to later slice into two boards, for a better chance of reducing cupping.  So if my kerf is about 1/8", and I want two boards that are about 3/4 after slicing(assuming no cupping).  That will give me room to plane on the back side if needed.  So that adds to 1 5/8".  How much will that shrink?  1/8"?  Adding the shrinkage would make is 1 3/4" green.  I could air dry them for awhile (6 months?) before putting them in the kiln(I don't have one... but I know a guy).  Any tips on kiln settings for this.  It's a Nyle/woodmizer kiln.  I think it's a 4000BF unit. He loads it with 2500-2800 BF.

[GeneWengert-WoodDoc]

I know of a company in northern WI that would use a 6/4 thick green piece of lumber, around 1.625”.  After drying, it was 8 % thinner max, but’s most were 7% thinner.  So, 1.45”.  Then they jointed and planed both faces with cup and surface roughness being eliminated.  I no longer recall the finished thickness, but would think it would be 1.32”.  Then they put two tongues and two grooves on the edges and then resawed into two pieces with a band saw. They then had two flat, t&g pieces, 0.6” thick with smooth on one side and rough on the other..

[scsmith42]

I'm taking your point in Scott.  Mill thick enough to later slice into two boards, for a better chance of reducing cupping.  So if my kerf is about 1/8", and I want two boards that are about 3/4 after slicing(assuming no cupping).  That will give me room to plane on the back side if needed.  So that adds to 1 5/8".  How much will that shrink?  1/8"?  Adding the shrinkage would make is 1 3/4" green.  I could air dry them for awhile (6 months?) before putting them in the kiln(I don't have one... but I know a guy).  Any tips on kiln settings for this.  It's a Nyle/woodmizer kiln.  I think it's a 4000BF unit. He loads it with 2500-2800 BF.

Depending upon where in the log the boards are milled from, your drying related shrinkage will be between 6% - 12% of green thickness.
Using your numbers, 1-5/8" dry will resaw into a pair of 3/4" boards.  Since you want the circular kerf to show you won't need to plane the outside.
For drying related shrinkage, figure between 1/8" - 1/4" depending upon the location in the log.
After 6 months of air drying 1-3/4" - 1-7/8" white oak the core of the board will be around 45% MC, give or take.  If you then load into the Woodmizer kiln you will need to have a system for adding moisture back into the kiln (I use a high pressure fogging system in mine).  You'll need to keep the RH% up around 95%, give or take, for about 60 days at 90F.
8/4 white oak is around a 4 month kiln run in an L200, and that's with a fogging system.  You will get a lot of mold development on the outside of the lumber unless you treat it with a fungicide after milling.
The biggest challenge with all of this is getting the thick boards the same MC% in the core and the shell.  If it varies, they will cup after resawing.
Gene - correct me if I'm wrong, this is just my personal experience.

[Brad_bb]

60 days in the kiln?  wow!  To reduce that should I air dry longer?

[GeneWengert-WoodDoc]

Scsmith42, I do agree with most.  I do think that since the wood has been exposed for 6 months to 80 F and 65% RH on the average, you could go into the kiln at the same RH and 90 or 95 F.  But I would suggest that for the first week, run the fans 18 hours a day.

Two advantages of planing the dry lumber before resawing are that you have a flat reference surface for the resaw.  Plus every piece will be the same thickness after resawing.

[Brad_bb]

Gene, that would defeat the  whole point.  The thick slab is circle sawn on two sides.  The plan is to then saw down the middle with my bandmill. If you plane the thick slab, you would be planing off the circle sawn marks.

[YellowHammer]

  With interest.  

I have a need for this type of paneling, or 4/4 wood.

[Andries]

I could air dry them for awhile (6 months?) before putting them in the kiln(I don't have one... but I know a guy).  Any tips on kiln settings for this.  It's a Nyle/woodmizer kiln. . .

. . . . the boards will be around 45% MC, give or take.  If you then load into the Woodmizer kiln you will need to have a system for adding moisture back into the kiln (I use a high pressure fogging system in mine).  You'll need to keep the RH% up around 95%, give or take, for about 60 days at 90F.
8/4 white oak is around a 4 month kiln run in an L200, and that's with a fogging system. . . 
The biggest challenge with all of this is getting the thick boards the same MC% in the core and the shell.  If it varies, they will cup after resawing. . . . 

So, if I've got this right, 2 months of 95% RH and another 2 months of a 'normal' white oak drying cycle after that? . . . and speciality fogging systems in the kiln?
All to get uniform dryness from core to surface? 
Seems like a lot of fussing around.
Suggestion, once you have your lumber milled, air dry for a much longer time (Brad, you said 6 months?).
Stack, sticker and strap with loading straps. As the stack shrinks, ratchet up the strap tension to keep the lumber under pressure and straight. 
Air dry as if you were aging whiskey in the cask, until the core and surface have equal MC's.
Then run the kiln cycle to take down the bound moisture in the wood.
Would this work ?