Warped charcuterie fix

[Scott Linge]

I've been lurking quite a while so thought I'd share a success story with a warped charcuterie board I created from scraps. It was dead flat when I finished it a few months ago, but then the winter dry warped the top to where it was convex by about 3/4 inch in the center. I knew putting pressure on the walnut edges could break the glue lines I so carefully mitered and jointed in.

The center board is kiln dried white oak about 1/2 inch thick so I wetted it on the bottom, added a little heat and slowly pulled on those edges only against a heavy oak under board till it was flat, took about an hour.

Then, I routed a shallow bed on three locations and glue/clamped the two maple and center white oak boards cross grain to the underside of the top but only in the original oak center. Carefully avoiding any clamp pressure on the walnut "wings". I tried this same technique on another trivet last year, but only used 1 inch wide strips and even three would not prevent a re-warp, so this time I used much wider boards to overpower the warp.

20210207_134301.jpg20210207_134224.jpg20210207_150500.jpg20210207_151605.jpg20210208_142450.jpg20210210_104217.jpg

[John TenEyck]

It looks good now, but if you glued those battens across the full width of the oak it might not look as nice next Summer.

John

[Lee Schierer]

I have to agree with John. If those battens were glued in cross grain I believe you will have additional issues with moisture changes.

How thick was that piece of oak before it got to be 1/2" thick? How much was taken off each side to get it to that thickness? How and where was this board being stored? Was any sort of finish applied? Was it applied to all sides?

[Scott Linge]

Thanks for naming them battens, I didn't know but it works! Cross grain full stop battens, that's what I did, but it's low risk in this case. The width of the oak is only 6.3 inches and it's quartersawn with near vertical grain so movement will be very small.

Lee, questions answered:
How thick was that piece of oak before it got to be 1/2" thick? 5/4 kiln dried rough sawn.
How much was taken off each side to get it to that thickness? Board was flattened, split and thickenss planed.
How and where was this board being stored? Garage Minneapolis MN 12 years.
Was any sort of finish applied? Mineral oil top, shellac bottom
Was it applied to all sides? Yes.

[John TenEyck]

Shellac on one side but not the other probably contributed to the problem. Shellac has the lowest moisture vapor transmission of nearly any finish. With mineral oil it's very high. That set up the perfect conditions for it to cup. Leaving out the shellac likely would have been better. Treat both sides the same.

John

[Scott Linge]

Thanks John, I'm new to this mineral oil treatment so good to know!!

[Ron Citerone]

That 5/4 split and planed oak makes me nervous. Just my initial thought after reading the whole thread. Has a great look!

[Lee Schierer]

Thanks for naming them battens, I didn't know but it works! Cross grain full stop battens, that's what I did, but it's low risk in this case. The width of the oak is only 6.3 inches and it's quartersawn with near vertical grain so movement will be very small.

Lee, questions answered:
How thick was that piece of oak before it got to be 1/2" thick? 5/4 kiln dried rough sawn.
How much was taken off each side to get it to that thickness? Board was flattened, split and thickenss planed.
How and where was this board being stored? Garage Minneapolis MN 12 years.
Was any sort of finish applied? Mineral oil top, shellac bottom
Was it applied to all sides? Yes.

So it was stored in an unheated garage with no environment controls. Moved it to a work shop, sliced into two boards, effectively removing half the wood from one side. Then applied unequal moisture resistant finishes to the top and bottom. Any one of those could have caused your cupping.

Wood should always be allowed to acclimate to the new environment for enough time to allow moisture stabilization. A 5/4 board could take a year to do that.

When removing wood from surfaces, it should be done as equally as possible from each side.

Finishing should provide equal coverage on all sides so that moisture changes occur as equally as possible.

I suffered a similar fate years ago with some wood stored in an unheated building in NW PA for 15 years and immediately started making parts from it. None remained straight or flat. I went out and purchased a moisture meter. I checked a remaining section of the piece of wood and moisture levels were 10% 2 weeks after it had come into my heated shop. My shop was only at 30% relative humidity and is heated 24/7 as it is serviced by the house HVAC.

[Scott Linge]

Lee, good tips. Sometimes I get surprised even when I expected 4 coats of high quality polyurethane to stop the moisture. These vanity under sink doors are 14 inches wide with flat sawn red oak 9/16 thick and the summer gap is zero and in this winter picture the gap is 3/16". The good news is they remained dead flat.
doors.jpg

[Lee Schierer]

Lee, good tips. Sometimes I get surprised even when I expected 4 coats of high quality polyurethane to stop the moisture. These vanity under sink doors are 14 inches wide with flat sawn red oak 9/16 thick and the summer gap is zero and in this winter picture the gap is 3/16". The good news is they remained dead flat.
doors.jpg

Here is a cabinet I completed in May of 2020 using some hickory that had been stored in my barn for 25+ years, stacked and stickered. I had it planed in November of 2019 and it stayed in my shop right after it was planed. Note the gap between and around the two doors.
IMG_2719.jpg

Here is the same cabinet after nearly a year in the same location through a heating season. The doors have equal amounts and type of finish on all sides. Again note the gap around and between the two doors.
IMG_0766.jpg

These doors have battens attached to the back, but have remained flat because the screws holding the battens allow the doors to move.
IMG_2721.jpg