Friday, November 19, 2010

Focus on wood - Walnut

Ah, walnut.  A beautiful wood and a nice wood to work with.  It probably shouldn't surprise you to hear me say that, seeing how often I use it.  Walnut offers a wide array of possibilities in terms of look, some of it quite striking really.  As a tree, there are 21 different species that can be used as timber, growing from Europe to Japan and from Canada to Argentina.  When we talk about walnut in woodworking, we are almost always referring to a black walnut.  Now from there, it will vary by region.  Typical examples being American black walnut, Claro walnut, and European black walnut. American black walnut comes from the eastern part of the U.S. and Canada. Claro walnut comes from the western part of the U.S. and Canada.   Each of these black walnuts will vary in color and grain a bit, but all have similar properties.

Walnut is hard, dense, and tight-grained.  It is used for furniture making, propellers, and prized for gun stocks.  In fact, if your rifle or shotgun has a wood stock, you can bet it is walnut.  No other wood is really used.  It was popular in the past for moldings and trim in houses.  In fact at the beginning of the last century the tree was being over harvested because of that purpose.  All styles run their course though (and then often come back. Remember bell bottoms coming back?  Starting to see 80's fashions return too.  I'm still waiting for day-glo to make its triumphant return).  Walnut was considered too dark and a bit dreary after a while in terms of use for trim and moldings around the house.  People started preferring golden oak.  This probably helped the survival of the tree a great deal.

The heartwood of walnut is a dark, tawny brown and is affected by how the lumber is dried.  Most is kiln dried which leaves it with a more muted brown color.  Air drying the lumber, however, will produce a deeper brown with some purple hues to it.  Hmm. The air dried sounds more interesting.  So why is most of the walnut kiln dried?  That's pretty simple really.  You can kiln dry lumber in a matter of days or weeks.  When you air dry lumber, it takes about one year per inch of thickness of the board.  And in the meantime, you get to go out once a month or so, disassemble the stack of wood, rearrange it, and then stack it again in a different order to keep the drying even.  Sounds like fun huh?

Walnut also produces a great deal of figured wood.  The most commonly used is walnut burl.  The picture up top has a walnut burl lid.  Walnut burl is the root of the tree.  You can also get walnut burl from, well. burls, that grow on some of the larger limbs.  Walnut burl is coarse and has a wild grain that goes just about every direction.  While this can present a bit of a challenge for woodworking, the results are often quite striking.  While walnut burl may be the most common, finding striking grain patterns are not all that unusual in walnut.  Basically, any time that the tree doesn't grow straight or is placed under some sort of stress, it will result in some sort of figuring.  The front of the box at the top shows an example of such an occurrence. While these results make working the wood more difficult (because density and grain pattern start to change, so how the wood behaves while planed or routed can radically change over the course of inches), I find it to produce much more interesting results in the end. 

Enough rambling for now.  Time to go make some saw dust.....