The Woods: Properties

The properties of wood vary immensely among different genus, family, and species.  Wood from different parts of the globe can be wildly different and surprisingly similar. Depending on your application, the properties of interest to you will vary.

For our use in electronic instrument cases, we want to select woods based on stability, durability, workability, and aesthetics.  Given that, we're interested in hardwoods with good hardness, density, and color.

Hardwood Versus Softwood

Hardwood versus Softwood; it doesn’t really mean what you think it might!  The classification of hardwood versus softwood has to do with the tree’s biological reproduction system (angiosperm-harwood versus gymnosperm-softwood).  Though generally speaking, hardwoods tend to be dense and hard, and softwoods the opposite…there are many exceptions.  Hardwood and Softwood doesn’t necessarily mean a great amount or lack of hardness. 

Hardness

Hardness is measured on the Janka scale in units of force; lbf.  Balsa (90 lbf) is a hardwood you can work with your teeth!  Yew (1,500 lbf) is softwood that’s harder than oak (1,300lbf).  Yellow Pine (900lbf) and Cherry (950lbf) are popular softwood and hardwood species with similar hardness.  Cottonwood (350lbf) is a hardwood most consider unsuitable for woodwork due to its softness. 

 So in short, use the Janka numbers to indicate a relative hardness that you can identify with.

Density

Density is measure of weight per volume, and determines how heavy or solid a finished piece will feel.  The higher the density, the more weight and heft a given panel will have. A high density wood can give a small panel a nice solid feeling, but on a large case the same wood might feel burdensome and inconvenient.  In woodworking, density is typically reported in units of pounds per cubic ft (lb/ft3).  

Natural Color, Stains, and Dyes

With a few exceptions here and there, the large majority of GMUSynth panels do not utilize stains or dyes, rather the natural color of the wood is used.  A large part of the wood selection is based on color. Since stains only penetrate just below the surface of the wood, it is beneficial to avoid using them due the change in color that occurs when the instrument is worn or scratched.  And while dyes do penetrate further, the problem still arises.  Stains and dyes are beneficial in commercial applications where it is desired to color match large numbers of products built from different woods.  But in terms of custom instruments, I think the unique color and patterns of each piece of wood is something to be embraced and celebrated, not muted and hidden. 

That said, most of the panels will have a coat of oil applied as the first step of the finishing process.  This oil is there to bring out, and sometimes deepen, the natural color of the wood.  The oil used varies by wood species but could include Tung Oil, Boiled Linseed Oil (BLO), Teak Oil, or even an oil varnish blend.  This all depends on the wood species...as different oils affect different woods...differently.