Stability of wood from a burl

[msweig]

Just out of curiosity, is wood from a burl decently dimensionaly stable, or does it typically move in more unexpected ways than straight grained lumber? I picked up a small piece of walnut burl for a few bucks that I saw somewhere, and was planning on using it to make a spokeshave because I thought it would look pretty good, but I'm not wanting it move in some unexpected way and screw up the hardware.

I'm planning on getting it to rough dimension, let sit in the shop for awhile, then true up. But the thought crossed my mind because I've never worked with burl before or read much about it.

Edit:
Here is a (crappy) photo of it. I'm assuming it is a burl due to the direction of the figure, but maybe I'm wrong. Smoothed and rubbed with mineral spirits.



Mark

[Ken Vick]

Since you are talking about a relatively small piece of wood, I think you will be fine to use it. The problem with burl is that the grain runs in all directions so the shrinking and swelling is not along just one dimension. Consequently, they develop cracks as the wood movement fights within the block. The smaller the piece, the less problem. Really chaotic burls won't have much structural strength so if this burl would make lights out veneer, you will need to consider if it has enough strength for your needs. Ken

[AHill]

Every burl bowl blank I have purchased had wax on every surface. I think that's a good indication of how stable burl is. Since the grain is running every which way but loose, cracks and splitting could occur just about anywhere as it dries. I recommend using paint or something like Anchorseal to protect the wood as it dries.

[msweig]

I'll smooth one of the surfaces and post a picture. I should say I'm pretty sure it is burl. Maybe it is just figured, but if it is the direction of the figure surprised me (based on my memory).

Mark

[Steve N]

I think a spokeshave is used to hard for burl wood. Just an opinion, can't say I have tried to make a tool from a burl, but they seem to last a long time, or start to self destruct early on, and that is using them on low stress objects. Now burl veneer is held together by it's glue, but solid pieces often aren't too sound as they dry. If you could think of a little pretty that just sat on an desk, that might be a better use.

One difference is if you could infuse the wood, like Dave Jeske does at Blue Spruce tools. His handles are tough, and he uses all kinds of wood.

[alnandy]

My company sells a lot of burls, running from 12" to 42" wide (that is not a typo) of big leaf maple, walnut, cherry, redwood, and some other species. For most of these species, the burl wood is quite stable and can be easily air dried. One warning; some burls have internal cracks, embedded bark pockets, etc., these can crack.

We cut our burls into 2" table top slabs and have them kiln dried. Our loss in the kiln is under 10%, so my advice is to cut your burl blank approximately 50% thicker and 20% longer and let it air dry about 1/2 as long as lumber of the same thickness (the shorter time comes from the fact that your blank is essentially a square billet and these dry much quicker than lumber).

Hope this helps.

[Isaac S]

Pretty nice figure on that wood, but it looks like a piece of crotch walnut, not burl. If that is what you have, I would be much more concerned about strength than stability. If I am see it correctly, the piece you have was cut right down the center or the crotch.

The picture below may help you see what's going on in your piece. Wherever the tree forks, the grain forms a "U" shape. Great for figure, but it also means that the grain on your piece of wood runs the width of your board, and not the length, and is probably not the best choice for a spokeshave.

[ianab]

I'd call that "Figured Wood" as opposed to burl. You can imagine that it's been cut from a section of wood like Isaac's picture.

If it's properly dry it should stay stable. Can be a problem to dry straight because there is often stress involved and changing grain direction pulls the wood in different directions.

But it looks cool, so it's worth messing with.

[Paul K. Murphy]

The wood you have is not a burl, but a crotch.
Do not make a spokeshave from this piece of wood. It is unsuitable for that purpose.
In order to be clear about why, take a glance at the board about midway between your stickers. The lines of color, the grain, run from the top to the bottom of the board's thickness. The grain does not go the "long" way.
Unsuitable.

[Steve N]

Unless you had decided other plans for that piece of wood, I'd make the spokeshave. Whack it on a stout work table a few times, if it blows up it's meant to be, strong like bull, and you are good to go. I think it would be beautiful. That crotch is just a half side, the weaknesses talked about are, deeper into the tree, on another piece of wood somewhere else, or in a burn bin. Make sure you show pics of your work.

How to build a spokeshave American Woodworker