Vintage Wood Log Nut Bowl

[Tony Maness]

I need recommendations on how to turn a wood log nut bowl and maintain the bark and prevent the bowl from warping as it dries.

 

[Mileseaton]

well as for the bark, you want a tree that was cut down in the winter.

 

[Bill Boehme]

I am guessing that you want an end grain bowl where the bark runs the full height of the exterior. That is the most difficult situation to keep the wood from splitting.

Sometimes applying thin CA along the cambium layer will keep the bark intact. Wood warps as it dries -- that's a given. The most common way to deal with that problem is to twice turn it. The wood is green the first time it is turned and the walls are left extra thick. Next, the bowl is left to dry for several months. When the wood has dried it is given a final turning to remove the warping.

 

[hockenbery]

Tony,

That shape is really difficult to dry because the differential in tangential an radial shrinkage.
In all woods the tangential shrinkage is greater than the radial shrinkage. You can find tables for most commercially sold woods
Basically the circumference needs to shrink more than the diameter.

This shape bowl is hard to impossible to air dry in most species. Assume a circular log

A10" diameter cherry bowl will shrink to a diameter of 9.6" which should have radius of 30.25" however the tangential shrinkage
says the wood wants to be 29.2" around. That means the wood must overcome 1" of movement.
With an 8" bowl the rim is till wanting to shrink .85" than the wood inside will let it.

First thing for success is to keep the bowl a small diameter.

Sassafras and black walnut are a couple of woods that just might work for such a bowl.

Sassafras has a radial shrinkage of 4% and a tangential of 6.2%.
In an 8" bowl the rim wants to shrink about .55" than it the wood inside lets it.

Black walnut has a radial shrinkage of 5.5%. and a tangential shrinkage of 7.8%
In an 8" the rim wants to shrink an extra .58"

Another suggestion is to cut the bottom thinner than the side wall maybe a 3/16-1/4 for the bottom and a 1/2" for the wood part of the rim.
The bottom can then push up or down a little bit something like a telescoping camp cup. Each growth ring squeeze the one inside out a bit. When wood is really thin this works really well.

Drilling a hole in the pith helps too.

You could probably use any wood and treat it with PEG.
This sort of turns the wood to plastic and keeps it from warping

Btw. We used to have a bowl just like that.

Good luck
Al

 

[Bob Howell]

I am making some 1" plates with natural edge, but I gave up on keeping the bark too. I have started with a 10" magnolia log and cut off two slices. Then boiled them for 3 hrs. They have dried 3 days and I plan to wait another week. Then turn them about 1/2-3/4" or so. Today I noticed they are covered with mold.

I have boiled wood before but it removed the color on a piece of apple wood. How ever the wood did not crack. That says a lot as the other pieces from the apple tree cracked up.

Easy to test.

Bob

 

[john lucas]

Keeping the Bark on is probably easier than trying to keep the Pith from checking. It won't warp as much if you use the trunk and has the pith centered. I would turn it so the bottom is thin and then turn a hole in the center. Let it dry slowly to try and keep the rest of the wood from checking. When it's dry I would remount it, turn the hole true and then add the center piece out of some dry wood.

 

[Bob Howell]

So I boiled the 10" disk I mentioned above and now, 6 days later they have began to split. So another rumored solution is now suspect.

Maybe I left some step out but I have cracks that kill this plan.

 

[hockenbery]

This is a near impossible shape to dry because the tangential shrinkage is more than the radial shrinkage.
Boiling won't stop all the shrinkage. Soaking in PEG will stop the shrinkage.

Magnolia should be a good choice.

An 8" diameter piece is going to have a better chance than a 10" diameter piece.

Also if you hollow it and leave a thin bottom. The bottom can push up or down as it dries like a collapsible camp cup.

Al

 

[john lucas]

Dave Barringer taught me a technique years ago. If you make the bottom cone shaped instead of flat, when it starts to shrink the cone will get longer (or possibly taller) and is less likely to check because the wood has somewhere to go. Turn the inside thin but instead of making it flat across the bottom make it sort of a gradually rising cone ending in the center nut platform. then shape the outside of the bottom the same way so you have a relatively thin bottom. Don't know if it works or not but worth a try. I suspect the type of tree has a huge amount to do with how and if it will crack. Many years ago I dried a bunch of dogwood limp sections that had the pith in them. Dogwood is less prone to checking but still will. I dried them by placing them in a plastic bag. I turned the bag inside out every day (or at least every 2 days). I did this until they were totally dry which I think tool several months. If that's the case and this is going to be a Christmas Present better get started now. 🙂

 

[Tony Maness]

So I boiled the 10" disk I mentioned above and now, 6 days later they have began to split. So another rumored solution is now suspect.

Maybe I left some step out but I have cracks that kill this plan.

keep me informed of your experiments

 

[Tony Maness]

Dave Barringer taught me a technique years ago. If you make the bottom cone shaped instead of flat, when it starts to shrink the cone will get longer (or possibly taller) and is less likely to check because the wood has somewhere to go. Turn the inside thin but instead of making it flat across the bottom make it sort of a gradually rising cone ending in the center nut platform. then shape the outside of the bottom the same way so you have a relatively thin bottom. Don't know if it works or not but worth a try. I suspect the type of tree has a huge amount to do with how and if it will crack. Many years ago I dried a bunch of dogwood limp sections that had the pith in them. Dogwood is less prone to checking but still will. I dried them by placing them in a plastic bag. I turned the bag inside out every day (or at least every 2 days). I did this until they were totally dry which I think tool several months. If that's the case and this is going to be a Christmas Present better get started now. 🙂

I received a call from an old family friend requesting a vintage bowl. From all the great responses, I am afraid I may have to call him back with explain that the process is not guaranteed. I think that the bowl is is still worth the challenge