Official Luthiers Forum!

I still have a few 'technical' questions that I need to research about processing tonewood. They might not change the way I do things but they might help me explain why I do certain things. Along that line I am starting to investigate the issue of drying and 'seasoning' wood. I think most of us understand the concepts of 'free' water and 'trapped' water, for a lack of the technical terms. Free water would be that which is outside of the cell walls and trapped is that which is inside the cell walls. We would, in general terms, call wood that has been dryed wood that has very little free water, and wood that has been seasoned wood that has the moisture largely removed from within the cell walls. Now I am speaking from memory of biology classes from 20 years ago in College, so I can be easily corrected here and I am going to review Hoadley's great book on this stuff. But what got me thinking more was that all of the wood inside the sapwood layer should be dead. Like I said I need to look into this a bit more. We do know that in the the spruce that I harvest that the inner portion of the tree is much dryer than the sapwood portion. So, is the inner portion, the heartwood, remaining moist because it is covered in an envelope of water and is therefore unable to dry further or is it still somewhat vasular? How much trapped water remains in cells that are no longer active and have been laying in place for a few hundred years? Anyway, to start down the road to getting answers to these (and a few others that are rattling around in my cranial cavity) I measured and weighed a couple of pieces of wood that I pulled from the bush yesterday (the last of the current tree is home now!!). Here are the pieces:





So when I measured and weighed these and compared them I found the following:

The sapwood weighed 13.05 g/in3 and the heartwood weighted 7.32g/in3. Sorry for the use of mixed measuring systems but that seems to be the way it is most reported in the lutherie circles! So that means that the sapwood is 1.78 times heavier than the heartwood by volume (I even included the bark which if removed would make the difference even greater!). Anyway, I will be looking at this further but would love to here more thoughts on this. Just for reference dries tops leave here usually about 3.7 to 4 g/in3, depending on the tree and how long I have had them. This current tree was felled on 3 June 2007. Off now to run sound for a freinds band in neighbouring community!!

Thanks

Shane

_________________
Canada

Hmmmmmmmmm

I find it really inspiring that a guy already providing some of the best wood in the world (Shane's client list and demand attest to that) is sitting around on a Saturday morning going 'how can I do this better?'.

You're going to be the Count of Conifers in a few years, I swear.

_________________
Bob Garrish
Former Canonized Purveyor of Fine CNC Luthier Services

I see a new avitar on the horizon - "Count Conifer" -  Hmmmmmmmm! 

_________________
Waddy

Photobucket Build Album Library

Sound Clips of most of my guitars

Hey Shane

Are you sure you are measuring your density correctly ?? I use grams/cubic inch as well, and I have never ever seen dry spruce that was less than 5.8 g/cubic inch. 3.7 to 4 is less dense than most red cedar  !!

Most Euro spruce and Engelmann comes in at 6.2 - 6.8.
Adirondack 6.8 - 8.0

Is your spruce really that light ??

Mark

Shane,

What is the grain structure like between the heartwood and sapwood?

If the tree grew fast at the start and then because of crowding went into a peroid of much slower growth then the outer newer growth would be much denser closer grain than the much lighter faster growing inner growth.

Most of the weight of the pieces comes from the harder winter growth instead of the lighter summer growth so that if the outer sapwood was growing slower then the weight of the denser winter growth rings would account for the high weight per cubic inch.

Hmmm...

Shawn

As I understand it, the bound water is not filling the cells, it's a thin layer on the surface of the cell walls bound by molecular attraction.

The sapwood is the part that still has some living matter in it, and I guess that would account for the extra weight. Not all of the cells are empty.

Al, I was referring to "dry" wood. The cells are empty but the cell walls have a thin layer of water molecules on them, and that layer grows thicker in high humidity and thinner in lower humidity as vapor pressure varies.

The best book I know of on tree biology is - 'A New Tree Biology' by Dr.
Alex L. Shigo, a former biologist for US Forest Service who started
dissecting trees in 1959 and continued for 20 years and in the process
gained more insights into trees and wood than, I hate to say this, you can
shake a stick at.

I tried to locate my copy of the book to investigate your questions, Shane,
but I'm afraid one or another or my cohorts has hauled it away.

You can look at the table of contents of "A New Tree Biology" at:
http://home.ccil.org/~treeman/NTB.html

A brief summary of the book and Dr. Shigo's work:
http://www.treedictionary.com/DICT2003/shigo/NTB.html

His consulting group - Shigo, Trees, Associates out of New Hamshire:
http://www.shigoandtrees.com

Hope you'll find this of interest & all the best,

John

sorry, I haven't discovered yet how get things linked up. maybe one of you
fellows out there can help me out with that.

j

[QUOTE=johnfgraham] sorry, I haven't discovered yet how get things linked up. maybe one of you
fellows out there can help me out with that.

j[/QUOTE]

Here you go John, second part of the tutorial for ya

_________________
My Facebook Guitar Page

"There's really no wrong way, as long as the results are what's desired." Charles Fox

"We have to constantly remind ourselves what we're doing....No Luthier is putting a man on the moon!" Harry Fleishman

"Generosity is always different in the eye of the person who didn't receive anything, but who wanted some." Waddy Thomson

Thanks, Rod

Links to my previous post:

"A New Tree Biology"

A brief
summary of Dr. Shigos work

Shigo and Trees, Associates

j

Here's a good one as well - tree biology terms with a little philosohy thrown
in:

The Techno
Tree Biology Dictionary

Scroll down a bit to the alphabet and peck the first letter of the term you're
looking for.

j

[QUOTE=Blanchard] Hey Shane Are you sure you are measuring your density correctly ?? I use grams/cubic inch as well, and I have never ever seen dry spruce that was less than 5.8 g/cubic inch. 3.7 to 4 is less dense than most red cedar !!Most Euro spruce and Engelmann comes in at 6.2 - 6.8.Adirondack 6.8 - 8.0Is your spruce really that light ??Mark
[/QUOTE]

I went and measured up a couple of sets from my stash. The weights are indeed higher than I indicated in my first post.



This set weighs 416 grams and when placed together as a pair measures .370 x 7.875 x 21.75. So it weighs 6.56 g/in3. It has about 24 grains per inch.




This set weighs 481 grams and when placed together as a pair measures .391 x 8.5 x 22. So it weighs 6.58 g/in3. It has about 16 grains per inch.

These sets are from two different trees from two different watersheds but the same regional area and are both Lutz Spruce. So I think my math is right and these sets are quite dry, the trees being down for over two years and the sets re-sawn for a number of months to over a year and stored in a heated area with about 50% humidity.

What is interesting now is that the heartwood from the tree mentioned above is only about 10% heavier than these dried sets and it has not been resawn dried and stored yet. Another thing to think about!!


Shawn, The sapwood on this tree actually has wider growth rings than the heartwood, that is not typical from my experience. Another interesting note from the trees above is that the tighter ring spacing produced the lighter in weight wood. And I think some of the first sets you got from me had ring spacings in the mid 40's and was even lighter than this wood shown. So probably the size of the dark rings (they are larger in the wider grained wood) may add to the weight as well. So it might be the accumulated width of dark grains that contributes to the weight. Is any of this important? Not sure but it is interesting to look at and may help people in determining what they would look for when selecting their tops and should definitely be part of the notes recorded when building guitars, they are recorded in my guitar making journal!

Shane

_________________
Canada

John,

Thanks for the links, I will indeed have a look at them in the next few days.

Thanks

Shane

_________________
Canada

Shane

Thanks for clearing up the density issue.

I'm really looking forward to trying out some of your spruce.
I'll be in touch !!!

Mark