Wednesday, April 29, 2009

Sitka Spruce

The soundboard of most acoustic guitars is made of softwood, generally spruce or cedar. Every once in a while you will see a redwood top, and I've heard of builders using koa (a Hawaiian hardwood) or mahogany. These are unique instruments in that the top, back, and sides are all made from the same wood.

The formula for 99% of the acoustic guitars made is softwood for the top, hardwood for the back and sides, and hardwood (generally mahogany or maple) for the neck.

By far the most popular softwood for a steel string acoustic is Sitka Spruce (picea sitchensis), which is found in the coldest regions of North America. It has the highest strength-to-weight ratio of any softwood i.e. it is both light and strong, properties that are crucial in a guitar top. If a top is too heavy, it won't vibrate, and in order to get it to vibrate you will have to thin it past the point of structural integrity. A guitar top has to be light enough to vibrate and create air movement, yet strong enough to withstand the app. 170 lbs. of pull from the strings.

Few woods can pull this off. Sitka Spruce shines.

Clark's guitar will be made of Sitka, with a twist: his top w
ill include a type of figure called "bearclaw" in which the grain unpredictably "squiggles", creating a striking effect. Especially under a finish, the bearclaw figure causes light to reflect differently so that the bearclaw almost shimmers. You have to see it to appreciate it. Here's a picture of Clark's Sitka top:


I've enlarged the picture to give you a better view of the figure. Although it's a little faint, if you look closely, especially at the top of the pieces, you can see that it looks like a bear has clawed the wood. Like I said, under a finish this figure shimmers almost like a jewel.

No one knows what causes this effect, and it doesn't happen in all Sitka. It does make the boards stiffer, so they can be thinned a little more than with a regular Sitka top and still be strong.

This has the potential to be a very beautiful guitar. I better not mess it up!

4 comments:

  1. Of the guitar's final appearance you write, "It (will) look like a bear has clawed (it)".

    In 2 Kings 2: 24 it is written, "Two bears came out of the woods and clawed 42 youths". Maybe you should name this guitar "Elisha's Defender".

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  2. Yeah, that's not my favorite story in the Bible. Kids make fun of Elisha's baldness and the bear kills them.

    Geez, get a sense of humor!

    Nope, the name is Eubanks #3, or Clark's guitar, or whatever Clark decides to name it.

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  3. Since it's a guitar, ow about "Larry's DeFender"?

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