Different Spruce? Sitka?

Construction and repair of Classical Guitar and related instruments
printer2
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Re: Different Spruce? Sitka?

Post by printer2 » Thu Jul 30, 2015 2:10 am

Did a hack neck reset, cut the joint and glued some wood strips in. Action is pretty high, have a temporary SS saddle in yet. Compared the volume to its sister bodied guitars and not all that bad. Lower volume yesterday mainly because I could not put too much into the strings without them buzzing. Not what I would call a tone machine but my nails are really short right now, better with a pick.

I am starting to get inspired. I wonder if I can make a guitar out of a 2x6, neck and body? Or make it a two piece top and back with a 2x8. might be able to make it for under $25 in parts not including the 2x6. So many ideas and not enough time in a day.
Fred

kefroeschner
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Re: Different Spruce? Sitka?

Post by kefroeschner » Thu Jul 30, 2015 3:21 am

Nice thread. One thing no-one mentioned is the age of the various samples discussed. It is my understanding that as wood ages the resins polymerize, much like epoxy but over decades or centuries, not hours. So new wood is 'squishy' and acoustically lossy, while really old wood is hard, stiff and rings. I have some dulcimer tops made of hundred year old redwood from an abandoned barn that ring like a bell when tapped.
1977 Asturias AST 60, signed by M. Matano
1979 Kazuo Hashimoto C-30
1970's Shinano No. 55
1970's Matsumoku 'Lyle' C-640
1971 CONN C-20
'De Gama' No. 5102
Dean Espana
Washburn C80S
Ibanez AEL 4012S 12 string
Several Dulcimers in work

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HNLim
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Re: Different Spruce? Sitka?

Post by HNLim » Thu Jul 30, 2015 12:39 pm

bacsidoan wrote:
Michael.N. wrote:I don't think I've ever seen a veneered neck on a modern Classical, they are often found on Romantic/Baroque Guitars and Lutes. The heel found on modern Classical guitars doesn't lend itself to being veneered, although there's no reason why a cone heel can't be done.
Picture of a maple guitar with AFB veneer neck built by Sebastian Stenzel, posted by rojarosguitar
DelSeb02.jpg
This gives me an idea! If ever I do buy an old Qvation classical guitar with a damaged top, I will definitely consider this form of neck construction.

Alan Carruth
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Re: Different Spruce? Sitka?

Post by Alan Carruth » Thu Jul 30, 2015 2:56 pm

kefroeschner wrote:
"It is my understanding that as wood ages the resins polymerize, much like epoxy but over decades or centuries, not hours. "

That's a common belief, but I've never seen any data. I have cut into spruce that was more than 150 years old and found pockets with runny pitch, so I'm not sure about that. There is, however, a documented change that alters the ratio of crystalline to amorphous material in the wood, and reduces the weight: hemicellulose degradation.

There are three main structural components in wood; cellulose , which makes up about 50% of it, and equal amounts of lignin 'glue' and hemicellulose 'filler'. Cellulose is a long-chain polysaccharide; little 'bricks' of sugar that are bound together end-to-end in a specific structure. These chains are organized into bundles that make up the fibers, mostly oriented along the grain. Because of the chemistry cellulose is very stable and hard to break down, and the fibers are strong and don't melt.

The fibers are glued together with lignin, which is, as I understand it, a phenolic resin. It's thermoplastic; softening somewhere around 108F (80C) and discoloring at around 300F (150C). It's also pretty stable chemically.

Hemicellulose is also a polysaccharide, but it does't have a definite structure because it's a 'branched chain' polymer. This leaves the molecules with a lot of loose ends, so to speak, that can react with water. It's the hemicellulose that actually absorbs moisture from the air when the humidity goes up, and causes the wood to swell. I'm told this also increases the damping factor; the rate at which the wood dissipates energy in vibration, and, of course, it gains a bit of weight.

Hemicellulose is not very stable chemically; with moisture cycling it breaks down into the CO2 and H2O that were put together originally to make the sugar 'bricks'. As the hemicellulose breaks down the wood becomes more stable because it can't take up as much moisture. It also loses a bit of weight and stiffness, but the weight goes down faster, so the ratio of Young's modulus to density goes up slightly. Over time this opens up little voids within the wood that reflect light rather than transmitting it, in the way that the air spaces in a snow bank make the transparent ice look white. New spruce tops are translucent, but old ones are opaque.

The loss goes at about 1%/decade, if memory serves, so it's slow. It's still significant, especially in terms of stability. This is the difference between wood that was recently cut and is 'dry', and old wood that has been 'seasoned'. Because hemicellulose loss is driven by moisture and temperature cycling, wood is most quickly seasoned in a place that's dry, but open to the air, so that it sees lots of changes in temperature and humidity. I've got some wood seasoning upstairs in my barn that must be getting better at a fantastic rate!

Hemicellulose degradation is probably also behind the phenomenon of 'shrinkage hysteresis'. Something like a guitar top gets a bit wider as the humidity rises, and shrinks as it gets dry. If you go back and forth from, say, 10% R.H.to 90%, and back, it's been found that the wood gets a little smaller for every cycle; it shrinks a little more when it's dry, and never quite swells back to full size when the humidity goes up. This probably has to do with the loss of hemicelluose and the consequent inability of the wood to take up as much moisture with every cycle.

Since the main 'crystalline' material in wood is the cellulose, and the lignin and hemicellulose are amorphous, as the hemicellulose goes away the ratio changes. It may not be that something 'crystallized', but rather that something that was amorphous went away. This is not to say that the resins can't or don't crystallize, but I haven't seen any evidence of that, and I know that hemicellulose degrades.

Marcus Dominelli
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Re: Different Spruce? Sitka?

Post by Marcus Dominelli » Thu Jul 30, 2015 3:02 pm

kefroeschner wrote:Nice thread. One thing no-one mentioned is the age of the various samples discussed. It is my understanding that as wood ages the resins polymerize, much like epoxy but over decades or centuries, not hours. So new wood is 'squishy' and acoustically lossy, while really old wood is hard, stiff and rings. I have some dulcimer tops made of hundred year old redwood from an abandoned barn that ring like a bell when tapped.
It's true, although some woods age differently than others. Old douglas firs gets so hard that you cannot even pound a nail into a 100 year old two by four without the nail bending!
Red cedar (thuja plicata) does not seem to change all that much, although it still gets harder when it's really old.

I'm making a double top with sitka spruce for the inside and outside skins. This wood was very old, and the wood is hard and stiff, even though the grain spacing is very wide. I doubt that I would have selected this wood if it were cut fresh. I think the reason it's so stiff is because of its age. It was cut over 50 years ago.

kefroeschner
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Re: Different Spruce? Sitka?

Post by kefroeschner » Thu Jul 30, 2015 3:36 pm

Alan: Thanks for the extensive thesis. So, it is the removal of hemicellulose that is really what is going on (not polymerization as I surmised) Thanks for the enlightenment. Helps to explain why wood cured underwater turns out so well. As to pitch pockets in old wood, I can attest to that as well: I am making some toe-rails on a boat we are re-building in Florida, using Southern Yellow Pine timbers salvaged from old construction and just laying around the yard. This stuff is well over fifty years old (former building siding boards) and when worked, the sawdust is still so sticky you can make 'snowballs' with it. Thanks Again!
1977 Asturias AST 60, signed by M. Matano
1979 Kazuo Hashimoto C-30
1970's Shinano No. 55
1970's Matsumoku 'Lyle' C-640
1971 CONN C-20
'De Gama' No. 5102
Dean Espana
Washburn C80S
Ibanez AEL 4012S 12 string
Several Dulcimers in work

printer2
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Re: Different Spruce? Sitka?

Post by printer2 » Thu Jul 30, 2015 10:31 pm

I had a house built out of Fir 2x4's and I cut into a couple to put a cabinet in. Thought the saw would burn up. Construction lumber is not dried to the extent that instrument or furniture wood is. This is most likely why new cut Fir could be used for construction. Over the years the moisture leaves the wood and causes the fibers to be less pliable and hard as a rock.
Fred

Alan Carruth
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Re: Different Spruce? Sitka?

Post by Alan Carruth » Fri Jul 31, 2015 12:27 am

'Back when' they used to build houses around here with dead green hemlock. They'd nail or pin things together and leave the fram to stand for a year before finishing it. The wood would shrink and get as hard as a brick. With all the shrinkage out of the way they could do the finish work without worrying about the frame moving, but it was hell driving nails. My sister used a lot of hemlock in framing here house: it's not very stable and hardens up very quickly.

I always get a kick when I drive by a lumber yard and see a pile of 2xs in the rain with a sign that says: "Kiln Dried!".

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Re: Different Spruce? Sitka?

Post by Dofpic » Sat Aug 01, 2015 3:01 am

One of the reasons I ask this question was i played a terrific cedar double top guitar at the GFA and since I prefer spruce I was considering the builder make me one. He said he only builds with Sitka Spruce as he thinks it works very well for double top guitars with Cedar underneath.
Spruce,2011Fritz Ober(maple), 2015 Eric Sahlin, 2006 Greg Byers(fan not lattice)2009 Eric Monrad(maple/Brazilian/spruce)
2012 Martin Blackwell(for sale), 2001 Dominique Field(for sale)
Cedar, 2014 Joshua DeJonge( for sale)

lsume
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Re: Different Spruce? Sitka?

Post by lsume » Thu Jun 01, 2017 4:41 am

Hokkaido Spruce seems to be somewhat rare but the preferred spruce for Yamaha's top of the line classicals. After watching a documentary about what made Stradivarius violins sound so great. As I recall, they discovered that the wood was especially dense due to weather conditions around the time that the wood grew. If memory serves, Hokkaido spruce is both rare and dense.

Dofpic
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Re: Different Spruce? Sitka?

Post by Dofpic » Thu Jun 01, 2017 11:30 pm

Marcus how did that sitka double top come out?
Spruce,2011Fritz Ober(maple), 2015 Eric Sahlin, 2006 Greg Byers(fan not lattice)2009 Eric Monrad(maple/Brazilian/spruce)
2012 Martin Blackwell(for sale), 2001 Dominique Field(for sale)
Cedar, 2014 Joshua DeJonge( for sale)

ivan
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Re: Different Spruce? Sitka?

Post by ivan » Fri Jun 02, 2017 12:59 am

lsume wrote:
Thu Jun 01, 2017 4:41 am
Hokkaido Spruce seems to be somewhat rare but the preferred spruce for Yamaha's top of the line classicals. After watching a documentary about what made Stradivarius violins sound so great. As I recall, they discovered that the wood was especially dense due to weather conditions around the time that the wood grew. If memory serves, Hokkaido spruce is both rare and dense.
But Yamaha top of the line models is not that good if we compare it with the real world class luthier made guitars like Dominique Field, Andrea Tacchi, etc. And for GC-82 (their flagship model), Yamaha use German Spruce, not Hokkaido.

Regarding the dense wood. IMHO, it is a matter of construction style of each luthier.
Luthiers who like to work with thin tops (like Joshia de Jonge, Paco Santiago Marin, Antonio Marin Montero, etc) always looking for stiff and denser spruce. These 2 attributes (stiff and dense) allow them to thinning down the top even more.
But for luthier who like to work with thicker top (like Andrea Tacchi, Edmund Blochinger, Jose Vigil, etc), usually they prefer a top with lighter weight, medium density, wider grain.

So denser is not always better.

Michael Propsom
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Re: Different Spruce? Sitka?

Post by Michael Propsom » Fri Jun 02, 2017 5:27 am

It's always interesting to see how a post can evolve away from the original topic. Some great posts and information. But, to address the original question, I've built a couple of classicals with Sitka tops. I was extremely satisfied with the the results. Both had excellent volume and tone.

As Brian McCombs theorized, yes, sitka (like all top woods) has a range--of both density and stiffness. In fact wood from the same log can differ. About ten years ago I bought about three dozen tops out of the same log. Some of the sets were as stiff as any sitka I have every had-with a strong fundamental tap which I've used for steel strings, while others were considerable more flexible and exhibited considerably less focus (i.e. more overtones) that have gone into the aforementioned classicals.

Grooveman JS
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Re: Different Spruce? Sitka?

Post by Grooveman JS » Wed Jun 07, 2017 3:13 am

Sitka Spruce, Its used a lot on steel string guitars & while we're on this; I wonder what you guys say about Adirondac Spruce .....this wood is used a lot on Arch Top guitars................does anybody know of a CG topped with Adirondac Spruce :?: :idea: :?:
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Jim Frieson
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Re: Different Spruce? Sitka?

Post by Jim Frieson » Wed Jun 07, 2017 8:01 am

I used to use Sitka . I liked it a lot . Great makers used " Geman " spruce and Brasilian rosewood so they became the woods of choice . Nothing wrong with either , that is what I mostly use
Clients turned up their noses at Sitka , more than a few times . The only things I found detractions were the colour , often brownish , but merely a cosmetic detail and it is possible to get quite white Sitka , and the fact I noticed the fan bracing seemed to telegraph more in Sitka and show up in polishing with shellac which has colour .
Hokkaido spruce ; Ezo Matsu . Matsu means pine , rather like Pino Abeto for spruce where Pino means pine . I found Hokkaido spruce almost seems to be a marriage of European spruce and Sitka . Anyways nobody is going to get piles of tops of it , it is hard to get , and I live in Hokkaido . I grab the odd piece from house demolition every now and then .
" German " spruce ; not much of that left I think . Dealers get logs from all over , cut and sell as spruce , but it is not German . I have tops from Bosnia that I cut there myself , unbelievably stiff and strong for its'relatively light weight . I also have other tops from Bosnia and elsewhere in Europe that are very flexible . European spruce varies in strength and is not a constant .

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