building the prototype

Below some pictures of the prototype building process:

In the first section of the building process I will cover the back and sides.

For my prototype I decided to stick to Indian Rosewood for several reasons:

  • It is readily available
  • It is good value for money
  • It is appealing (Most guitars have a dark wood body and Indian Rosewood is ´the´wood of choice for many builders)
  • It has excellent musical properties (You can find a detailed article about wood, its musical properties, choices and design aspects in the ´All about wood´section of the site.
  • And, most importantly for my ´first´projet, it is relatively easy to work with.

 

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The back bracing merely serves the stability of the box, and the standard choice for these braces is mahagony. As you can see I added a decorative purfling stripe between the 2 bookmatched rosewood planks. Profesionnal luthier places like LMI or Steward MC Donalds sell these ready made if you don´t want to make your own. For my prototype project I decided not to add to much complexity (but ONLY in the parts that do not have any impact on the sound of the instrument) and so I got my wood decorations from LMI.

I decided to laminate the sides for the following reasons:

  • Lamination is lighter than plain rosewood. Through lamination I can keep the rosewood of the sides thinner without losing stability. This helps to keep the instrument light.
  • Laminated wood becomes much stiffer than same thickness ´massive´wood. From a sound point of view, you want or sides as stiff as possible. They should not absorb sound vibrations emitted from the top by participing in the movement of the box. The stiffer the better from that respect. Thus, laminating is not a cost reduction factor, but it helps improve the sound of the final guitar.
  • Lastly, laminated sides are stiffer and better protected against cracks or other damage caused by physical contact with furniture, chairs etc; 🙂 or humidity variations.

Often times you will hear me mention that certain design decisions will have an impact on the sound. Some of these aspects will be very subtle (like the side lamination introduced above) but I believe that the sum of all these little details will be notable in the final instrument. Somehow the difference between an above average `factory built´guitar (like the Hanikas for instance) and a professional luthier hand-build (and individually optimized) instrument lies in these details. If they improve the sound quality, they are often times very time-consuming details that will in the end make the decisive difference. Since these are individual adjustments on a guitar by guitar basis, it is logical that they cannot be included in an automated cost-effective mass production process (as good as it may be). Hence a hand built and optimized guitar will very likely outperform the best factory built models.

Did you ever wonder why the vast majority of serious and performing artists (at least all the ones I know about) stick to luthier built instruments in stead of buying much cheaper top of range of the shelf guitars…. If they were ´as good´ as the manufacturers want to make us believe, why is it then that I have never seen a Hanika Meisterklasse being used on stage by a profesionnal classical guitar player for a ‘classical’ music concert? (My point is that I have never seen one. If you know about one, please let ne know and shall correct my above statement on the fly!!)

Again, I don’t want to say anything bad about Hanika or similar brands. they are defenitely worth their money, and I believe that they are about the best your money can buy in the 3 to 4000 price range. You gotta try a handmade instrument to see that there is something else out there. The difficulty is that most music stores only offer the standard ‘factory’ brands, and unless you’re willing to go and find individual luthiers to try their instruments, or if you happen to know sb who’s the happy owner of one of these guitars there is no easy way you will be able to compare them.

its a bit like with cars 🙂 if you have never heard of or seen a Bentley or Rolls Royce then chances are you will believe that the mercedes S class provides the best that car luxury has to offer. And you will probably love you s-class (if you decide to buy one). So unless you want to find yourself in a similar situation than me -thanks to my teacher who let me play his concert classical guitar-, I suggest you stay away from the Bentleys and become a happy owner of an s-class…. unless or course you’ve got the necessary cash not to worry…. (building your guitar is one thing…. building your own equivalent of a Rolls-royce is a totally different story… hmmmm 🙂

All right, back to building…

Neck design decisions:

The neck on the prototype model is made out of quartersawn spanish cedar. For stability reasons (and for the looks) I decided to inlay a stripe of ebony hardwood. You’ll be able to see that on the upcoming pictures:

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Since all my guitars feature a traditional spanish heel the neck of the prototype is build following this design principle. It will be anchored to the sides during the assembly process, and its angle locked in place at the time the box is closed by gluing he back on.

It is important to decide about the scalelength very early-on since the spanish heel design requires to cut the slots where the sides will meet and ‘lock into the heel’  at the precise position of the 12th fret, which on a standard 650 cm scalelength will be exactly 325 mm down from the nut. The nut sits precisely above the neck-headstock join so that it remains straight and aligned with the future glued-on fretboard. If you chose a 640 scalelength, then the slots for the sides will be cut 320 mm  down from the neck/headstock break line. (To be precise, you actually do need to add the width of the nut to this measure, since the nut will sit in front of the fretboard, and you need to reserve the necessary space for it.

Top design decisions:

Most concert classical guitars feature either a spruce (in all its variations, european, engelman, sitka etc.)

Since the top is to a large extent responsible for sound creation, it is by far the most important component of your instrument (when it comes to sound). I make no compromise whatsoever when chosing the tonewood for the top. My preference goes to Mastergrade European spruce from Bachmann. It has an above average stiffness to weight ratio which allows to work the tops really thin by still keeping enough stiffness without compromising integrity of the structure.

Talking about integrity: the bracing pattern and layout also plays a predominant role in the top design. I’ve opted for an asymetrical design that is derived from John Bogdanovich’s design. I have decided to improve it somehow based on logical conclusions I derived from Ervin Somogyi’s explanations in his books and articles talking about vibration modes of the tops. The bracing and the thicknessing of the top cannot reall be discussed seperately, and I spend a great deal of time adjusting both in order to reach the targeted stiffness. It’s hard to explain what that is. Simply put: When flexing the constructed top in your hands (before its glued on)  you want to reach a good level of springback without making he overtall structure too flexible. At the same time I try to target an average top taptone pitch between the notes of f and g at the area of the center brace under the bridge. Finally, I adjust the hight and width of the braces as well as the thickness of the top in itself to make it thinner and more flexigle to he sides at the lower bout for a good bass response. Ideally you will end up with a good distribution of different notes for the various fan braces still keeping f too g as target for the cenger brace under the bridge area of the top, It is quite a time consuming exercise simply because there is no room for mistakes. If you push it too far, you’re screwed (pardon the expression) since you cannot really but any wood back on. To mitigate that risk, i usually don’t push the top tuning to the extremes at this stage. I leave a very little “too much material” as overall top thickness until the guitar is fully assembled.

Below some pictures documenting the above:

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On the pictures you can see my go-bar deck. It´s like a upside-down table that is installed and fixed above the solera with the guitar top installed face down on the solera. This allows to install the bracing bars and to use fiberglass sticks (very flexible) to press the bars against the top when gluing them in place. This is much more practical than using clamps. The actual deck I built myself and the bars I got from LMI. You can of course use flexible wooden sticks in stead of the fiberglass ones I bought if you prefer. Gluing the bracings on with the top installed on the solera helps to install the dome in the top. Once the braces are dry glued, they tend to lock the slera´s domed shape into the top. Expect some spring-back but it will do the trick. I also shape the lowerside of the bracing bars (only the lowerbout fan braces because the upper bout of the top is not domed) to that 25´´ radius. This is done by sanding the side that will be glued to the top over a domed dish of the same radius. (Check the tools and equipment section of the site for information on those dishes and where to buy them). The shaping will have the braces adhere to the domed radius, and will reduce some of the springback I talk about before.

Some pictures about the side building:

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Don´t bend wood that is still thicker than 1.5 mm, or chances or breaking it are too high. It is incredible how you can ´feel´how bending becomes easier the thinner the sides. Somewhere before I talk about my decision to laminate the sides of the prototype. You can see that on the pictures. (the pictures with the many clamps 🙂 )

 

I actually glue the bridge on before finishing the instrument. This allows me to string her up without the finish, and to finetune the top while actually playing the guitar. In other words, if I’m not totally happy with the sound (balance between strings, sustain, overtones, loudness, projection etc.) I can still improve things by sanding selective parts of the top and braces (directly on the top to reduce top thickness or through reaching inside the box through the soundhole to amend the braces thickness).

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Once all the components completed its guitar assembly time. You start by fixing the front of the sides to the heel. You need to trim the front of the sides so that they match the angle and depth of the side slots. I won´t explain this myself since John Bodganovich does this in great detail in his book and dvds. A few pictures of my prototype box assembly below.

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The top is glued to the sides while the top is lying on the solera upside down. You glue the top on before the back. As long as the back is not on the angle of the neck remains adjustable even though the top is ready glued on. To glue the back on it is important that everything is perfectly aligned on the solera, and that the neck is clamped to the neck support of the solera. Remember that the neck support of the solera is sanded to a ramp that starts at the front of the soundhole and continues in a straight line down to the front of the neck. This area is about 4 mm lower than the soundhole height. To maintain this neck angle in the finished instrument you need to clamp the neck to the solear so it does not move when applying clamp pressure while gluing the back in place. After the back is glued on you won´t be able to adjust that angle anymore.

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Above you can see the one clamp that fixes the neck to the solera.

You don´t need many lateral solera side holders anymore once the sides are glued to the top since this does already lock the outside body shape of the box in place.

Small advice, leave the dimensions of the top and back a good cm larger then the target box size, all around the perimeter. This enables you to ´slide or move´ things around to make sure that there won´t be any open spots where you might have cut things to tight. Another reason is to avoid unncecessary tension in the box, I tend not to force things in place too much. If you bend your sides on a bending iron like I do, then there will be slight differences in the bending shape on both sides. The solera side holders (the little sticks on the side of the solera) are ment to lock the sides into the shape of the box template that you decided to follow. If the sides are a little bit asymetrical, then you are required to really ´force´then into shape. If your top or back follow that template closely, then you have no choice but force things in place, or the top won´t cover the sides completely. The end result will be a box with tension where the sides and the top and back will be under a lot of tension. Leaving the top and back larger leaves more room for flexibility, and chances that slightly asymetrical sides will still be fully covered are a given. So less force required to squeeze everything to fit, hence less tension in the finished instrument. A box under tension will obviously vibrate less than a ´relax´box that is under no tension. Hence avoiding tension will have a notable impact on the sound of the instrument.

I usually keep the instruments in the white (without finish, and stringed up) for about 2 weeks during which I regularly play them, and I try to have 2 guitars in work at the same time, so that I can mutually compare them whle fine-tuning the tops in turn.

Gluing the bridge on before finishing the guitar means a lot more work in putting the shellac on the top, since the bridge is in the way. This is another one of these elements that you should expect from a hand-built luthier guitar that factory guitars do mostly not provide.

A profesionnal instrument is fine-tuned until the target sound quality is reached.  This means that nothing is left to chance. Unfortunately this process takes a lot of time. Since “time” is the number one cost factor of any guitar, you will understand why factory guitars hardly provide this service. Top of the range factory build guitars will adjust certain things by hand, like intonation, which can anyhow only be done on the finished instrument, but these will not reserve 5 to 10 days for a decent guitar player who happens to be a luthier as well, just to be able to compare various models, and keep working on the top thickness of each one of them throughout, all this before starting the finsishing process. It would just be too expensive, not to forget that you need very experienced people to perform these fine-tunings. (I’m not saying that I am very experienced because I do it, but I recogniwe its value, and I do my best…. and learn by doing… and I hope my 10th guitar will still be better than my current 3!)

Sometimes I play and record the same piece on 2 guitars, then do little adjustments, repeat the step, and compare the variations between the 2 recordings. Since your ears get tired, you need to leave it alone for an hour, and then come back and decide about the next step…

Some various building pictures that don´t really fit any of the above categories.

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Some of you might think that this documentation is too high-level and incomplete. And you are absolutely right.

My intention is not to explain it all in detail. I merely want to show what an amateur like myself was able to achieve once he or she has done her homework. In other words, I want to introduce those elements that seem most important to me, and I want to tell you where you find all the details that will need to understand before getting started.

I would not be able to explain things as well as John Bogdanovich or Ervin Somogyi do in their publications that I introduced earlier. So if I managed to awaken your curiosity, and if you decide to build your own guitar, then please buy those books, and John’s DVD set, and study it all in great detail. This is where you find all the step by step instructions.

My work and this site shall provide sufficient proof that it is actually in reach, and I want to give you the confidence that you can also do it.

Finally some pictures of my first frensh polishing attempt:

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The first 2 show the back when I decided it was good enough. Some of the others are work in progress on the back. The last picture below I decided to keep seperate because it shows the difference between a pore-filled side and what it looks like before pore filling.

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On the lower half of the back I had already started the porefillig. I use pumice and alcohol only. No previous porefilling before the frensh polishing. No toxic epoxy or equivalent needed in a traditional frensh polish. And the first 2 pictures in the gallery above should convince you that frensh polishing is not ´that´ difficult and does not take magical power or years of experience as some want you to believe. However it does take a lot of patience. Count 2 weeks to finalize the frensh polishing of one guitar, and about one hour per day. This however includes the initial load, the porefilling, and the final bodying and polishing. There is no sanding required at all, and you don´t need any carpolish or other polishing material. Only shellac, pumice (for the pore filling) and alcohol, and patience. After you are done let the instrument dry for another 2 weeks. Using her before is looking for trouble since the shellac will not be completely dry.