Sitka and mahogany orchestra model

Discussion in 'Acoustic Heaven' started by Freeman Keller, Oct 2, 2019.

  1. dreamingtele

    dreamingtele Friend of Leo's

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    I actually like Mahogany for back and sides better than rosewood or any other wood.. for the top, I want an Adirondack.. but any spruce would be okay!

    love your builds!
     
  2. Freeman Keller

    Freeman Keller Tele-Afflicted

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    I'm sorry, I didn't take any pictures of joining the plates on this one, but here is a previous build where I did. I shoot the edge with a plane and true it with a carpenters level with some double sticky back tape on it. I put waxed paper on my work bench and a piece of wood or metal like a yard stick under the seam. Coat it with Titebond, clamp a couple of pieces of wood tight against the edges, then pull the yard stick out and clamp it down flat

    IMG_1504.JPG IMG_1506.JPG

    I happen to be using the top of my go bar deck in that picture 'cause it lets me put clamps all around. Putting the yard stick under the middle gives me just enough clamping pressure and that long clamp helps in the middle.

    I use Titebond (original) for almost everything I do. If I make a dovetail neck joint I will use HHG for that because I know it will need to come apart in the future but my hide gluing chops are good enough that I feel comfortable using it for the entire guitar. My other glue exception is thin CA which I use for bindings and inlay.
     
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  3. Freeman Keller

    Freeman Keller Tele-Afflicted

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    Thank you. Good red spruce (Adirondack) is getting so hard to find that I've mostly used Sitka. However I did get in on a buy of ten sets of Lutz spruce tops. Lutz is apparently a hybrid of Engleman and Sitka and is almost as stiff as Adi - I have built three guitars from it that have turned out to be little cannons. These are Lutz over Brazilian and Madagascar rosewood parlors - tiny guitars but incredibly loud

    IMG_2970A.jpg

    I've used both rosewood and mahogany for backs and sides and like it equally. I've got some really stunning quilted mahogany down in the wood room that I want to match with some of that Lutz.... Just what I need, another guitar.
     
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  4. dreamingtele

    dreamingtele Friend of Leo's

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    oh man, those are looking good!

    I like to put a heavier gauge on acoustics to drive the top harder, hence my choice for the Adirondack top.. I use 12's..

    I'm not sure if Im correct with my assumption, but whenever I play a rosewood side and back acoustic, it has some sort of metallic sound to it, while Mahogany is warmer, a well rounded tone I kind of like to hear when I play acoustic.. but Ive also had an all mahogany acoustic, and while its really nice, its a bit too warm for me..

    One guitar that surprised me is the mid-priced Cort L300VF, with Solid Adi top, but mahogany ply back and sides.. it was loud and the more I play it harder, the louder it becomes.. I did buy it because its my ticket on a "poor man's Martin Authentic OM-18 1933" and to compliment my acoustic collection, but I sold all my acoustics to focus solely on electric for my gigs.. but it was the acoustic i played more than my more expensive ones.. enough to fit it with LR Baggs anthem pickups..

    https://www.cortguitars.com/product/item.php?it_id=131

    [​IMG]
     
  5. Wallaby

    Wallaby Tele-Meister

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    Cool clamping and photos, thanks for sharing it, and your glue comments.

    I've edge-joined using rope-and-wedge clamping before, I was just curious. Clamping material that will buckle is a neat challenging puzzle that has multiple solutions.
     
  6. Freeman Keller

    Freeman Keller Tele-Afflicted

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    Sweet guitar - I think I would like that. FWIW, I don't consider 12s as "heavy" - most of my finger style guitars get them altho I might bump up to 13's if I know I'm going to be down tuning and/or playing slide on it. If you want heavy strings (and adirondack and mahogany), this is a long scale ladder braced 12 string that I built a few years ago
    IMG_2008.JPG

    It is strung with cables, tuned in the cellar and absolutely roars.
     
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  7. dreamingtele

    dreamingtele Friend of Leo's

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    Love this! LOL

    well getting used to 10's on acoustic, the 12's were heavy for me.. hehe.. I havent tried 13's I bought one though, but I thought about the neck on the Cort, The truss rod is almost maxed on 12's.. if I put 13's I may end up maxing out the truss rod and not have a decent action...

    so yeah.. getting a really nicely built Adi top with hog back and sides, OM body, loud and balanced bass and highs, would be the dream!
     
  8. Freeman Keller

    Freeman Keller Tele-Afflicted

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    Back to your regularly scheduled built thread. Next step in my parallel world is to profile the back braces. Nothing fancy, just a nice little parabolic shape - more for looks than anything else.

    IMG_4922.JPG

    IMG_4925.JPG

    And we have four partially done sub assemblies

    IMG_4926.JPG
     
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  9. Freeman Keller

    Freeman Keller Tele-Afflicted

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    We could have a long and interesting discussion about strings for acoustic guitars - gauges, composition, tunings.... Most of mine are designed and braced (which we are coming up to on the OM) for what the industry calls "lights" (0.012 to 0.054 or so) and total tension at concert pitch of about 165 pounds. Those little parlor guitars in post #23 are strung that way, my other small bodied acoustics as well. That big old 12 string is strung 13 to 56 (but remember that there are twice as many) but it is also tuned to B or C and has about 250 pounds of tension. Leadbelly's old Stella was strung with 16 to 70 (really!) but tuned to A so it was almost playable. At least by Leadbelly.

    Your Cort was designed for 12's and there is no reason it can't be set up with nice reasonable action and low relief with that gauge strings. It won't feel like a strat, but that's quite OK.
     
  10. Wallaby

    Wallaby Tele-Meister

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    I'm looking forward to tuning the braces!
     
  11. Freeman Keller

    Freeman Keller Tele-Afflicted

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    OK, here we go. We could have a long discussion about all the theory behind voicing the guitar, however I believe that if you ask 10 luthiers how they do it you will get 12 answers, all of them correct. So lets just do it and if anyone is interested we can talk about why.

    I start by roughing the scallops

    IMG_4932.JPG

    And then tap and flex and wave the top around in the air and chisel away some more wood

    IMG_4934.JPG

    and do it some more until it looks like this

    IMG_4939.JPG

    At some point I decide that is sounds/looks/feels the way I want it (what ever that means) so I stop. Questions?
     
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  12. Wallaby

    Wallaby Tele-Meister

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    Coooool! Do you do it all with the chisel in the photo?

    By tapping and waving I am guessing you're looking for flex in the top ( at the edges? ) and some kind of resonance or ringing. What do you look for or listen for?

    Do you ever inspect inside other guitars to learn its bracing and try to correlate its sound to its bracing?

    I've read about using blobs of blu-tack in strategic places to understand what changes in the bracing might result in, tone-wise. Is that an approach that's only useful after assembly, or is it something you might do before?
     
  13. Deeve

    Deeve Friend of Leo's Silver Supporter

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    Love those pics -
    thanks for continuing to share

    Peace - Deeve
     
  14. Freeman Keller

    Freeman Keller Tele-Afflicted

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    1 - chisel and little ebony plane. It is a really cool feeling to watch those curls of wood come off the brace

    2 - that was somewhat tongue in cheek - everyone who "voices" a top has some method of exciting it - they tap or thunk or flex or hold a loud speaker in front of it or hit it with a little ball or hammer. I've tried a lot of these and basically come back to flexing and tapping - listening for the sound to become "musical". (I took my wife to a voicing seminar by John Greven at one of the GAL conferences. Her comment was "so that what all those weird things you do are about..." John knows why he does it, I'm just going thru the motions.

    What I try to look for/listen for is a change in the sound from a dull "thunk" to a bell like rinnnngggggg. Sometimes I think I hear it.

    3 - I look inside every guitar I work on or play. I take pictures, I write things down. I talk to and listen to people who I respect. I have a lot to learn

    4 - I have heard of people adding mass to various parts of the guitar - bridge most often - to try to change the sound. Most of the time I want to remove more mass - I have reached inside guitars to finess the braces and I have an old Martin that has had the braced scalloped thru the soundhole. Most of the time I think less is better.

    There is so much that can be said about braces and so much more to learn. I mostly build different models and sizes each time but I have had a couple of opportunities to make the "same" guitar - in that case I try to make a small change to see if I can detect it. Sometimes I even think I can, but I'm also reminded by all those studies about psycho-acoustics and double blind listening tests and it makes me wonder.....

    I'll get another chance to work on the top tone after I get it glued to the rim. People do feel that that makes a big difference
     
    Last edited: Oct 10, 2019
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  15. tubedood

    tubedood Tele-Meister

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    Looking great Freeman! Do keep us posted.
     
  16. Wallaby

    Wallaby Tele-Meister

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    VERY interesting, your insights are much appreciated.

    I think you're right wrt psycho-acoustics and blind listening studies. The appreciation of straight-braced pre-war instruments, or even ( gulp ) ladder-braced tops are good examples. But maybe they DO sound good in their way.

    Maybe lively-feeling and musical-sounding resonance is a primary goal, and past that attempting to eliminate flaws ( boominess, woofiness, dead frequencies, etc. ).

    Like distilling spirits from 2 or 3 ingredients only ( barley, water, fire ) and then waiting 10 years to see how a new technique worked, I find it just amazing how today's designs were slowly discovered over time using brute-force trial-and-error and inspiration.

    Today's builders continue and advance continuous traditions that are hundreds and thousands of years old. I'm glad to be able to experience the results!
     
  17. Tonetele

    Tonetele Poster Extraordinaire

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    God Job! Juat as did the same with minimal saws,tools etc. Good luck.;)
     
  18. Freeman Keller

    Freeman Keller Tele-Afflicted

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    I have been part of one blind listening test (Alan Carruth's infamous sound port study) and have followed several others. Lets just say I am very skeptical whenever someone tells me what a certain tone wood sounds like or different nut materials or bridge pins or any of the infinite number of variables on our little wooden boxes.


    I for one really like ladder braced guitars. That big old 12 string in post 26 is ladder braced, SelMacs are ladder braced, many of the wonderful old blues guitars were not X or fan braced. I think that ladder bracing works best with some other design decisions (floating bridges, tail pieces) but it can also give a guitar a punchiness that you'll never hear with X bracing.

    IMG_1883.JPG

    So many ways to skin this cat.
     
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  19. Freeman Keller

    Freeman Keller Tele-Afflicted

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    The back braces and some of the top braces are let into notches in the kerfing. The ends of the X, the UTB and maybe the tone bars, altho some builders just taper them to nothing. I've always notched mine - it does stiffen the rim a lot.

    When I'm carving the braces I just put a little piece of scrap next to the end and pare the brace down to that height - you can see a dark piece of wood next to the first back cross brace. It is just a cutoff from a side or back - probably about 70 thousands thick - and I just use it as a depth gauge while scalloping.

    IMG_4922.JPG

    I'll use that same little scrap to check the depth of the notch in the kerfing.

    IMG_4937.JPG

    Trial fit the top and back until they just snap into the notches

    IMG_4935.JPG

    This is a good time to clean out the neck pocket

    IMG_4936.JPG

    I have tried a variety of methods of clamping the top to the sides while gluing - spool clamps, a bunch of quick clamps, both in and out of the mold. I like to keep the rim in the mold to avoid any twisting but that makes it difficult to get enough clamps close enough. The go-bar deck offers a solution. I put some sandpaper on the 16 foot radius dish and lay the top on top. The sand paper keeps things from moving when I apply the bars.

    IMG_4939.JPG

    Since I've sanded the rim to fit the radius dish it should clamp the top evenly all the way around. Cross my fingers and smear some glue on the rim

    IMG_4940.JPG

    Flip it over and pop it onto the top

    IMG_4941.JPG

    Apply some clamps and bars - the long pieces of MDF are simply cauls spreading the clamping pressure out

    If you don't believe that a go-bar deck can apply some serious (but well distributed) clamping pressure, look at the top of this one. That is two pieces of 3/4 MDF - not real structural material but still pretty strong - look how the bars have bent it

    IMG_4942.JPG

    Put this away while the glue dries
     
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  20. BB

    BB Poster Extraordinaire

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    Beautiful work Freeman.
     
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