D15m has a plywood back???

[chazmo]

Terminology notwithstanding, my 1967 arched-back F-50R is a rosewood laminate, but the base wood (middle wood in the "sandwich") is definitely *not* rosewood, guys. You can see this in the picture of the endpin hole where the inner and outer layers are distinct from the lighter middle. While this this is evidence only about the sides of the guitar, I assume the back is laminated the same way. Hans has already shown through the magic of photography that one of the other '67 arched rosewood backs that he has in his archives in fact had to be thin veneers which were definitely sliced from the same log as mine.

Are you guys certain that your laminated arched mahogany backs are actually multi-ply mahogany? Does anyone have an endpin picture of a D-15M to look at, or are the sides actually solid? I'm just curious.

Hans, is my '67 Hoboken example of arched lamination just too unique to be compared with the rest of the product line? I kinda' thought from our earlier discussions that perhaps this was similar to the process that they were using on the arched-laminated maple F-50s of the time. Is that incorrect (I wouldn't be surprised)?

 

[GardMan]

Chazmo,
It is my understanding that the sides of the arched back D-25 and G-37/D-30 are solid (don't know about the D-15 or other models)... I certainly can (and have) pulled the end pins and look(ed) at my two. I don't recall them looking laminated.

Given that the F-50 (as opposed to F-50R) had/have arched maple backs, I wonder if the center ply on ( at least the sides) of your arched back F-50R (Cap) is maple? Certainly looks light in color, like maple. If the back was the same way... rosewood veneer over maple... which tonewood would dominate the sound? How does it compare to your later "solid" F-50R (I am sure you posted a comparison... back when you rec'd Cap).
D

 

[chazmo]

Chazmo,
It is my understanding that the sides of the arched back D-25 and G-37/D-30 are solid (don't know about the D-15 or other models)... I certainly can (and have) pulled the end pins and look(ed) at my two. I don't recall them looking laminated.

Given that the F-50 (as opposed to F-50R) had/have arched maple backs, I wonder if the center ply on ( at least the sides) of your arched back F-50R (Cap) is maple? Certainly looks light in color, like maple. If the back was the same way... rosewood veneer over maple... which tonewood would dominate the sound? How does it compare to your later "solid" F-50R (I am sure you posted a comparison... back when you rec'd Cap).
D

Next time you pull the endpin on yours, Dave, I'd be interested to know what you find. I don't doubt that the sides on yours are solid, actually, but it'd be good to confirm that.

Y'know it's really hard to tell, but I think the middle wood on Cap's sides is -- dare I say -- some sort of particle board like what most people think of when they think plywood. It could be a layer of maple, but that wouldn't be my first guess. Of course, I know from Hans that the inner and outer layers are grain-matched slices of the same Brazilian log that was used on at least one other (and probably several) of this year's models. I think the back is done the same as the sides.

Hans also told me that Guild worked with a furniture vendor during this period, as the equipment to actually create the lamination slices was not something the Hoboken folks had direct access to. It may be an incorrect assumption on my part that the maple laminations that New York, Hoboken, and later Westerly guitars built for arched maple F-50/F-412 backs were done in any similar way.

I didn't ever really write up a direct comparison of Cap with its younger, solid, flat Westerly brother, Dave. My impression that the '71 is more resonant and a little more typical of what you expect from a rosewood-bodied sound. That said, the soundboard on Cap is not original, and I think it's German spruce rather than Sitka, so that may also be part of the equation. Of course, even though Cap is a great player, what I love it is its mojo... To buy a guitar like that from its original owner and to know all that cool stuff about it, well, that's part of what makes it a real gem to me.

 

[bek]

I have worked in a factory which made plywood, although it was more a construction-grade material than what is under discussion here. We made sheets of half-inch to one and one-eighths inches in thickness, all of softwoods. After I left for a different line of work, they shifted production to thinner sheets, with the same softwood cores but with hardwood faces (and sometimes backs, as well). They used the same machinery and techniques to make the fancier plywood, but never used the particle-board referenced earlier. If I were to make plywood (or "laminate") for this application, I would consider making it of three thin pieces, all with the grain oriented in the same direction, for flexibility. The plywood we made was all with the alternating-grain-direction-layers layup, which is very ridgid and dimensionally-stable, but I don't know whether it's the best thing for luthiery. Offhand, I would think so, for a formed back, but what do I know?

 

[adorshki]

Shortly after I bought mine, when I found out the backs on D25's were laminated, I made a point to look at the grain patterns inside the guitar. My D25'S at home and I'm at work, but I'm pretty darn sure when I inspected it I noticed the grain on the inside was actually 180 degrees reversed from the grain on the outside. This made sense to me as it would tend to make for a stronger composite and probably reduce the chances of splitting. I seem to remember seeing somewhere that there are actually only two layers though. HANS?

 

[bluesypicky]

I'd like to do a comparison between mine (arched back & spruce top), and the rarest of the D-25's, the arched back with mahogany top...

I think someone here at LTG has one? We gotta get together

Close but no cigar.... My all hog has a flat back.
You're welcome for the sound check anytime you're cruisin' down South Florida though!

 

[dreadnut]

Alright Hans or HideGlue or Workedinwesterly, who can give us the birdseye-lowdown on the laminates?

 

[killdeer43]

I stopped by the best, local plywood supplier this morning on the way to my shop and went into the back room where the "good stuff" is. The head buyer showed me their "aircraft-quality" 1/16" luan mahogany plywood. We sandwiched three pieces together and I could feel the whole thing strengthen each time a layer (ply) was added. I saw that with proper lamination, I could easily cut out a sturdy, usable pattern for a guitar back.

Further research revealed the basic concept behind the arched backs: three layers of similar/suitable veneers first laminated together and then placed in a machine that is in effect a mold that has both male and female sides to press the wood into the desired depth/shape. I'm sure that some heat and humidity are part of the molding process, as well.

Just like any sandwich, what you put between the slices is up to you, Dagwood!

**The supplier also said that he wonders why so many people think that "plywood is evil."

Joe

 

[chazmo]

Lamination and lutherie is a really interesting conversation, guys. Strength and durability are pretty much a given. A laminate is always a great choice for a traveling guitar or one that simply has to adjust to radical climate variances. The question with most laminates is whether you've deadened the sound since the wood no longer vibrates the way solid wood does.

These days, I know Tim McKnight uses a lamination process on soundboards and backs where he uses a Nomex honeycomb as a middle layer which isolates the inside wood and lets it vibrate. The outside wood doesn't influence tone and neither does pressing the guitar against your body. This is an example where lamination enhances the resonance of the wood. Plus, since the inside of the guitar is not what you see, you can play all kinds of interesting games like using different tonewoods in different sections of the inner box... It's fascinating.

What I don't know with Tim's Lutz-type tops or "double backs" is whether these inherit the durability of other laminates. I imagine they do since a nomex honeycomb is incredibly strong, but probably not to the level of a traditional glued-together wood sandwich.

Anyway, neat stuff.

 

[drive-south]

I'll just mention that in regular plywood, the total number of plys is always an odd number.
Plywood always has 3,5,7,9 plys so that the wood on each side has the same orientation.

Laminated wood for guitars can have 2 plys, 4 plys, etc. since all the layers are running in the same direction.

I believe that banjo pots have been made using this process for a lot longer than guitars.
Most wooden banjo pots have a cap attached to the edge so you can't see the laminations or plys.

Besides Guild another guitar maker that has taken advantage of laminates is Alvarez Yairi.
Use of laminates is pretty common in the classical guitar world.

drive-south

 

[bek]

I haven't tried to confirm this, but I have heard that most wood-bodied resonators use plywood for strength and stability, all the tone-stuff being taken care of by the cone and well (if any).

 

[drive-south]

I think that is probably true of most Nationals and Dobros. A resonator/bridge assembly is pretty heavy. I doubt a solid spruce top could support all that weight, plus the inertia of the vibrating cone.

I'll take one Estralita Dlx 12-string please. It would be quite happy parked next to my Style O, and my Guild 12s.

drive-south

 

[bek]

I heard you have to have a license for a 12-string reso.

 

[kitniyatran]

Terminology notwithstanding, my 1967 arched-back F-50R is a rosewood laminate, but the base wood (middle wood in the "sandwich") is definitely *not* rosewood, guys. You can see this in the picture of the endpin hole where the inner and outer layers are distinct from the lighter middle. While this this is evidence only about the sides of the guitar, I assume the back is laminated the same way. Hans has already shown through the magic of photography that one of the other '67 arched rosewood backs that he has in his archives in fact had to be thin veneers which were definitely sliced from the same log as mine.

Are you guys certain that your laminated arched mahogany backs are actually multi-ply mahogany? Does anyone have an endpin picture of a D-15M to look at, or are the sides actually solid? I'm just curious.

Hans, is my '67 Hoboken example of arched lamination just too unique to be compared with the rest of the product line? I kinda' thought from our earlier discussions that perhaps this was similar to the process that they were using on the arched-laminated maple F-50s of the time. Is that incorrect (I wouldn't be surprised)?

Somewhere I have a Fender "Frontline" "magazine"/catalog from, I think, 2001, with a Guild section, where it says the D25 has a layer of maple sandwiched between the mahogany, but I don't know if this applies to any other era of arched back construction, or how reliable the description even is. I DO know my D25NT(1995?) sounds AWESOME.

 

[adorshki]

Much as I'd love to think my '96 would have maple between the mahogany, Chazmo's explanation on Tim McKnights methods seems to indicate the middle layer(s) don't affect tone that much unless special materials/processes are used. I'd think it'd be a pointless use of the maple unless maybe for hardness? Or is maple actually more economical than the 'hog anyway so why not? (Ithought maple was more expensive?) Also see Hans' answer to West R Lee's question to him about how well he was doing when he thought it was all 'hog laminate, Hans said: "you're doing fine, West"... Would seem to imply it IS all mahogany... Is this another one of those questions whose answer will be revealed in Vol 2 of "the book"?
It just occurred to me this probably one of those tests with several correct answers! :lol:

 

[chazmo]

Much as I'd love to think my '96 would have maple between the mahogany, Chazmo's explanation on Tim McKnights methods seems to indicate the middle layer(s) don't affect tone that much unless special materials/processes are used. I'd think it'd be a pointless use of the maple unless maybe for hardness? Or is maple actually more economical than the 'hog anyway so why not? (Ithought maple was more expensive?) Also see Hans' answer to West R Lee's question to him about how well he was doing when he thought it was all 'hog laminate, Hans said: "you're doing fine, West"... Would seem to imply it IS all mahogany... Is this another one of those questions whose answer will be revealed in Vol 2 of "the book"?
It just occurred to me this probably one of those tests with several correct answers! :lol:

Al,

I'm not sure you interpreted me correctly. I think most laminated guitars that you'll find out there (not Guilds!) get a bad rap because they're designed like solid flatbacks... the problem (I think) is that the laminated back and sides swallow up some of the sound. The Guild use of an arched back makes good use of the reflection of sound and not necessarily the resonance of the back. But, maybe Guild laminates are done with thinner slices; I don't know.

Tim's method is a pretty recent development in the guitar world, and indeed I think the intent there is to isolate the inside wood from the outside, which is almost the opposite of what you get with a normal laminate where everything is completely glued up together and stiff.

I'm just thinking out loud.

 

[killdeer43]

Plywood, laminate, substrate, OSB, glulam, scalloped bracing, ad infinitum.
Bottom line: if we know nothing else, do we love the way our Guilds sound? I do! :wink:

Joe

 

[chazmo]

Plywood, laminate, substrate, OSB, glulam, scalloped bracing, ad infinitum.
Bottom line: if we know nothing else, do we love the way our Guilds sound? I do! :wink:

Joe

You sure got that right, Joe. My JF-30-12 and my F-50R are arched laminations, and my F-512, F-50R, and G-312 are solids. Don't ask me to choose.

 

[adorshki]

Much as I'd love to think my '96 would have maple between the mahogany, Chazmo's explanation on Tim McKnights methods seems to indicate the middle layer(s) don't affect tone that much unless special materials/processes are used. I'd think it'd be a pointless use of the maple unless maybe for hardness? Or is maple actually more economical than the 'hog anyway so why not? (Ithought maple was more expensive?) Also see Hans' answer to West R Lee's question to him about how well he was doing when he thought it was all 'hog laminate, Hans said: "you're doing fine, West"... Would seem to imply it IS all mahogany... Is this another one of those questions whose answer will be revealed in Vol 2 of "the book"?
It just occurred to me this probably one of those tests with several correct answers! :lol:

Al,

I'm not sure you interpreted me correctly. I think most laminated guitars that you'll find out there (not Guilds!) get a bad rap because they're designed like solid flatbacks... the problem (I think) is that the laminated back and sides swallow up some of the sound. The Guild use of an arched back makes good use of the reflection of sound and not necessarily the resonance of the back. But, maybe Guild laminates are done with thinner slices; I don't know.

Tim's method is a pretty recent development in the guitar world, and indeed I think the intent there is to isolate the inside wood from the outside, which is almost the opposite of what you get with a normal laminate where everything is completely glued up together and stiff.

I'm just thinking out loud.

HI Chaz; I was more focused on whether there was actually maple in the lamination. Your observation seemd to indicate (to me, although maybe I DID misunderstand) that there probably wouldn't have been much acoustic reason for it in that era with those construction techniques. So really I guess I'm just asking "If they DID use maple, why?" 'cause I thought it would be more expensive than all 'hog.
Enjoy reading your posts by the way. If you haven't noticed I love the technical stuff about the finer points of construction and technique, even though like killdeer, I wouldn't care if it was laminated with junk mail in the middle if it sounded like they do! :lol:

 

[chazmo]

Much as I'd love to think my '96 would have maple between the mahogany, Chazmo's explanation on Tim McKnights methods seems to indicate the middle layer(s) don't affect tone that much unless special materials/processes are used. I'd think it'd be a pointless use of the maple unless maybe for hardness? Or is maple actually more economical than the 'hog anyway so why not? (Ithought maple was more expensive?) Also see Hans' answer to West R Lee's question to him about how well he was doing when he thought it was all 'hog laminate, Hans said: "you're doing fine, West"... Would seem to imply it IS all mahogany... Is this another one of those questions whose answer will be revealed in Vol 2 of "the book"?
It just occurred to me this probably one of those tests with several correct answers! :lol:

Al,

I'm not sure you interpreted me correctly. I think most laminated guitars that you'll find out there (not Guilds!) get a bad rap because they're designed like solid flatbacks... the problem (I think) is that the laminated back and sides swallow up some of the sound. The Guild use of an arched back makes good use of the reflection of sound and not necessarily the resonance of the back. But, maybe Guild laminates are done with thinner slices; I don't know.

Tim's method is a pretty recent development in the guitar world, and indeed I think the intent there is to isolate the inside wood from the outside, which is almost the opposite of what you get with a normal laminate where everything is completely glued up together and stiff.

I'm just thinking out loud.

HI Chaz; I was more focused on whether there was actually maple in the lamination. Your observation seemd to indicate (to me, although maybe I DID misunderstand) that there probably wouldn't have been much acoustic reason for it in that era with those construction techniques. So really I guess I'm just asking "If they DID use maple, why?" 'cause I thought it would be more expensive than all 'hog.
Enjoy reading your posts by the way. If you haven't noticed I love the technical stuff about the finer points of construction and technique, even though like killdeer, I wouldn't care if it was laminated with junk mail in the middle if it sounded like they do! :lol:

Thanks, Al. Back at ya'. I love talking about that kind of stuff. I have no real background in guitar construction or repair, so I just absorb what I can. And, as a somewhat recent Guild adopter it's always fun because there've been so many changes and there's so much history to learn about with these guitars.

Best wishes!