Rick Turner
Well-known member
The subject of "what is the best wood for..." keeps coming up here, so I thought I'd get a discussion going re. just what the properties are that make "tone wood" out of a timber. For the sake of discussion, I'm going to use the popular names, but I will post a list of the Latin names in a day or two. I'll also be talking about "real acoustic" instruments, not some of the inexpensive ones like all-birch Stellas or the more bling oriented acoustic electrics.
With violins, you have literally centuries of work by luthiers virtually defining the tone by use of spruce for the tops, maple for backs, sides, and necks, and ebony for fingerboards. With guitars, the range is a bit wider for tops with spruce, Western red cedar, mahogany, and redwood being used; for backs and sides, mahoganies and their ilk and various rosewoods have ruled, with cypress for Flamenco guitars, maple for archtops and some flattops, and more recently walnut, myrtle, and a whole range of alternatives coming on strong as the traditional wood become harder to get.
With ukes, it all starts with koa. Why? Simple...it was the most commonly available wood on the Hawaiian Islands, and it happens to be fairly close to mahogany in it's requisite properties. It's also beautiful.
So what are the properties that make certain woods appropriate for certain parts of the instruments?
Stability
Stiffness to weight ratio (aka Young's Modulus)
Resonant Q
Density (not the same as above...)
Ratio of cross grain stiffness to longitudinal stiffness
Toughness (resistance to breakage)
Tensile strength (not the same as stiffness)
Compression strength
Workability (related to toughness)
Ease of gluing (oily woods are difficult)
Ease of finishing
Availability
Cost
So the appropriateness of a wood is a recipe. You can't take any one or two of the above qualities and ignore the rest. All of the above qualities are quantifiable, too, and the US Agriculture Department has a fabulous Wood Handbook with a lot of the numbers and ratings. When you see the actual numbers, you start to see just why spruce makes sense, for instance.
More to follow, I'm sure...
With violins, you have literally centuries of work by luthiers virtually defining the tone by use of spruce for the tops, maple for backs, sides, and necks, and ebony for fingerboards. With guitars, the range is a bit wider for tops with spruce, Western red cedar, mahogany, and redwood being used; for backs and sides, mahoganies and their ilk and various rosewoods have ruled, with cypress for Flamenco guitars, maple for archtops and some flattops, and more recently walnut, myrtle, and a whole range of alternatives coming on strong as the traditional wood become harder to get.
With ukes, it all starts with koa. Why? Simple...it was the most commonly available wood on the Hawaiian Islands, and it happens to be fairly close to mahogany in it's requisite properties. It's also beautiful.
So what are the properties that make certain woods appropriate for certain parts of the instruments?
Stability
Stiffness to weight ratio (aka Young's Modulus)
Resonant Q
Density (not the same as above...)
Ratio of cross grain stiffness to longitudinal stiffness
Toughness (resistance to breakage)
Tensile strength (not the same as stiffness)
Compression strength
Workability (related to toughness)
Ease of gluing (oily woods are difficult)
Ease of finishing
Availability
Cost
So the appropriateness of a wood is a recipe. You can't take any one or two of the above qualities and ignore the rest. All of the above qualities are quantifiable, too, and the US Agriculture Department has a fabulous Wood Handbook with a lot of the numbers and ratings. When you see the actual numbers, you start to see just why spruce makes sense, for instance.
More to follow, I'm sure...