I can't keep my end grain cutting board flat

[Trace Beard]

I'm making an end grain cutting board for a charity auction (neighbor has cancer) and I can't keep the board totally flat. It's the wood whisperer design with purple heart and hard maple. I've had the wood in my unconditioned shop for years.

I used my drum sander to get the board flat and after 100 grit switched to my rotex sander to 150 grit (I didn't skip any grits along the way).

The board will be dead flat and smooth after sanding, I come back several hours later or in the morning and I can feel a slight difference between the maple and PH. I realize that different woods shrink and expand at different rates but since this is the 1st project that I haven't given away I want it to be perfect.

I plan on using mineral oil and paraffin wax as the finish.

What can I do to keep it flat?

Trace

[george wilson]

Is the sander getting the wood warm or hot? that could cause something to subsequently shrink a bit. Try hand sanding it smooth in a place and see if it stays the same.

[Trace Beard]

It doesn't get hot but does get warm. I'm probably chasing my tail on this one. If I bring the board inside it stays flat but take it outside and it swells. Maybe I need to let it swell and then bring it inside and see if it contracts and gets smooth again. hmm

Anyway, thanks for your help.

trace

[Tom Hargrove]

Trace -

The Woodwhisperer reported two or three weeks ago that his endgrain cutting board blew apart after getting wet on one side, but not the other.

I tend to think that gluing two different kinds of wood together in a checkerboard/endgrain pattern would be inherently unstable, and subject to serious movement problems due to changes in humidity, or exposure to liquid water. It might be more stable if the wood is saturated with finish, which would slow down the moisture exchange that is causing your cutting board to move.

However, they sure are pretty.

[Trace Beard]

Thanks Tom for the heads up. I'll have to send out an email to everyone I've given a cutting board to and tell them to be careful.

Trace

[Ben Rivenbark]

putting small feet on one side of the board to raise it about 1/8 of an inch off the surface of the counter (or more) is a good practice to follow with cutting boards to ensure that if something is spilled and not noticed, the board doesn't pay the price.

Most of the knife nuts on knifeforums really dig their cutting boards, and typically buy a board from "the boardsmith" (a google search will yield a website with lots of beautiful boards) and they typically come with feet on them unless requested otherwise.