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It's me again! Hi everybody. Can anyone tell me why you would want medullary ray figure in your soundboard and what purpose does it serve vs a soundboard without it?

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Thanks To All:
Lee
Sikeston,Mo.

Medulary rays are sign that the peice is near as poss to perfect quarter sawn.
if you see good strong medulary rays in a top the chances are will be nice and stiff as the grain will not be more than 5 degrees off quarter.
the stronger the rays the closer the quarter.
also if your top has even medulary rays across the board its a good sign that there is minimal run out due to twist.
If you have patches of rays or rays at the bottom of the piece and not at the top the you probably have run out and the top wont have an even stiffness across the radial face.
if you find this in a top this top wont make a very good guitar and would be graded down to A grade becouse of it.

this said even if you do have have good medulary's you should still check the end grain for quartering and check the stiffness.
just becouse a top is high grade visualy does not mean it will be stiff or make a nice guitar.
medulary silking is not a aestetic quality it has a important role when checking for quality.

another test you should do on all tops is the light test for run out.
find an electric light source and hold the top so that a band of light shines across the top.
if the light is in the same place on both pieces then the top is run out free.
if the light is higher on side than the other then you have runout and the top should be avoided.
this obviously works better if the top has been planed but it will work with a fresh cut top too.
this is a fool proof method for checking for run out and works every time.

I hope this answers you question,

joel.

For the most part I agree with Joel. Except that I don't thick thoughts about run out as black and white. Just look at all of the pictures of Dave Mathews (from the Dave Mathews Band) Taylor Guitar. The soundboard always look like it is made from two different pieces of wood. That is a sure sign of runout yet it is owned and played by one of the top players in the world made by one of the best factory producers who likely knew the guitar would been seen by millions of people (read potential customers!)

Medullary ray display is indeed the first sign of a well cut top. But if the tree was split very straight you could still have runout induced by poor processing, i.e. the top is well quartered and the rays show but the top was saw not parallel to the split face of the block. I hand split before I saw my tops to address this as much as possible. Having said that, most Englemann and likely Euro Spruce has twist in the tree and as a result every one of those tops will have some degree of runout yet they can still make fabulous guitars in the hands of builders who are aware of the runout and take it into account when they build.

It is my observation though, in the way that I process and the wood that I process, if the medullary rays are displaying strong then the wood will be still and will typically tap well and should result in potential for a fine guitar, the rest is up to the builder. If a top is cut even slightly off quarter the rays begin to fade immediately, Cupiano and I discussed this and he referred to it "fuzz" rather than "silk".

Anyway, I just thought I would add a bit to Joel's comments

Good Luck

Shane

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Canada

Also some spruces like Carpathian or Red (and some German I have), even when perfectly 4sawn do not necessarily exhibit "silk", especially with wide grain specimen. Nothing to do with stiffness. I've seen perfectly 4sawn and super-silky Englemann and Italian tops that were quite floppy.

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Laurent Brondel
West Paris, Maine - USA
http://www.laurentbrondel.com/

Agreed. silking is not a sign of absolute stiffness. It is, however, usually a sign of relative stiffness. In other words, a top cut to show strong silking will probably be stiffer across the grain than if the same top had been cut slightly off quarter and showed no silking. Which one will sound "better" depends entirely on the application.

Mark

The meds are little bundles of cells that run across the grain, at right angles to the annual rings. They are there to transport sap in to the still-living cells within the sapwood, and they are there in all woods. They're really small in ebony, though! Since wood cells are stronger and less stretchy along their length, the meds make the wood stronger and stiffer across the grain when they run parallel to the surface. Thats why, for example, fiddle necks are cut with the ring lines parallel to the fingerboard surface, rather than perpendicular the way we cut guitar necks. The meds in the fiddle's headstock help keep the pegbox cheeks from splitting. Good meds in a guitar top mean that the wood has as high a cross grain stiffness as it can have, which, as Mark points out, may not be much. Still, anything free...

I would expect a Taylor with a lot of runout to sound better. They are so massive and heavily built I would expect one with a lot of runout to be a lot less stiff than one with none at all.

I don't know that runout per se hugely affects stiffness....

Thanks to all who replied. Sorry I have not answered before now but we had a terrible ice storm that came through on Monday and caused a lot of power outages here at home and we were luck enough to be included. The info was great guys and thank you for your time.

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Thanks To All:
Lee
Sikeston,Mo.

shorter grain = less stiff, no?

If the runout is severe I would expect it to have a signifigant impact.