Custom Classical Guitar Build Log – ALMA

The brief is for a custom classical guitar following traditional design and construction, with a more contemporary decorative scheme.

As my Alma classical follows the structural designs of Torres and Hauser  it is an ideal starting model to work from.

The decorative scheme will include a non-traditional rosette inlay design, using tonewoods matching the guitar build. The idea is for a “heart” in contrasting woods, and for “simplicity” and is left open to further ideas at this stage.

A Torres inspired head-piece silhouette also with a similar heart motif in contrasting wood. Final design details for the head-piece are also left open at this stage, as a definite conclusion hasn’t yet been reached.

I’m working on some drawings for both the rosette and head-piece and discussing ideas with the client.

Design Process

I derive the dimensions of the body by starting with the scale length of the guitar. Calculating the body length as a fraction of the scale. I calculate the bout widths to fractions of the body length, the idea is to create a sound board that provides a place for all frequencies to resonate.

25.6 inch/650.24mm scale length.
String width at nut 46mm
Neck width at nut 52mm
String width at saddle 59.5mm
Neck thickness at nut 23mm, at 9th fret 25mm
Body length 490mm (3/4 of the scale length)
Lower bout 368.5mm (3/4 of the body length)
Upper bout 274mm (5/9 of the body length)
Waist 245mm (1/2 of the body length)

A robust heel and neck is requested. Like myself, the client has very large hands that negotiate the heel with ease. He prefers the solidity this gives to the neck and the body/neck joint.

A wide, flattened oval neck profile. 25mm at the heel, tapering to 23mm at the nut. In this case the exact profile at 1st and 9th fret were specified and provided by the client. 15 degree head stock angle.
Standard (non-raised) finger board height.

A non-traditional compound curved finger board profile. Almost flat between 2nd and 5th string, then increasing in curvature to the edges . The client has a particularly curved index finger when fully extended for a Grand Barr, we hope the custom fingerboard to be far more comfortable.

String action to be “on the low side” but not so low as on a flamenco. The client plays a crossover finger style of mixed genre on the classical guitar. The action will be finalised during set up of the nut and saddle.

Materials:
Solid AAA grade Cedar sound-board.
Solid AAA grade American/Black Walnut back and sides.
African Mahogany neck with Ebony centre reinforcement.
American/Black Walnut finger board, Head-piece veneer and bridge.
A more harmonious collection of tonewoods could not be wished for with well matched densities. All very enjoyable to work with, I’ll be a happy luthier during this build!

Finish:
Traditional, hand applied finish only. Shellac over oils. Minimal grain filling of the walnut (during the french polish sessions using FFFF pumice). The overall request is a minimal finish for maximum resonance.
This guitar is destined for a life in the stable, low humidity of inland Spain. It will be cared for greatly by its owner. So emphasis is on the finest, lightest finish to allow the guitar to resonate as freely as possible. Improving the dynamics tremendously. Combined with the tightened upper bout and robust heel, and some selective thinning of the soundboard, I hope this guitar to respond to the most subtle of playing with a particularly strong fundamental, good presence of overtones and high partials.

 

Templates, shims and cauls…

Dimensions as per the client brief.  I refine the curves and draft a head-piece design.

I then trace and create templates for the sound board and head-piece silhouettes.

I cut and glue up a laminated assembly board, clamping shoe and various shims and clamping cauls that will be tailored to build this guitar.

 

 

 

 

 

 

The neck and head-piece.

I begin construction with the neck. I square, flatten and refine selected mahogany neck blank and heel block. Cut the scarf joint/ head-piece, refine and glue. Refine and glue heel block. Mark neck width. Mark and cut heel slots for side fit and wedges. Cut rebate for Ebony reinforcing, select and cut Ebony quarter sawn, refine and glue into neck. Initial carving of heel. I hand carve every heel to custom requirements of the client.

 

 

 

 

Head-piece.
I thickness and refine the walnut head-piece top veneer. We’ve decided on a single black sycamore veneer against the mahogany neck/head stock, then a single white, then the walnut head-piece top veneer. This theme will continue throughout the build with black and white sycamore purflings. I glue up the head-piece veneer laminations. Cut head-piece silhouette to template and refine. Cut tuner peg slots and holes and refine.

 

 

 

 

 

 

 

 

I finalize the head-piece motif design with the client and apply.
In this case, an additional, circular disc of mahogany of similar thickness, will fit over the walnut head-piece and be framed by the larger middle curve of the Torres shape. With more b+w veneer lines between it and the walnut. Then a heart will be cut out down through the veneers and through the mahogany head stock to the back of the head-piece.

Finally the head-piece has come together nicely. I’m really pleased with the results. There will be just a little more taken off the thickness of the mahogany disc/heart during finishing preparations. The client has had full creative input with me in decisions along the way. The result is a unique and simple expression of the client’s love of the Antonio de Torres guitars.

The Sound Board.

I thickness the selected AAA grade Cedar book-matched sound board halves to nominal 2.8mm. I will selectively thin the sound board later when tuning the constructed guitar body. After the centre joint is glued up, I finalize the rosette design with the client and apply. In this case book-matched walnut will form the “rosette” inlay with a mahogany disc and heart motif to match the head-piece. As cutting out the heart through the sound board is a bad idea we agree to inlay a walnut heart into the mahogany disc. All will be lined in black and white sycamore.

 

 

 

 

 

 

 

 

Sound board bracing.

I select spruce for sound board braces and tone bars and split to quarter grain. Then cut the full set of blank braces, tone bars and grafts. I draft, cut and refine arch templates for the sound board lower cross brace and the four back braces.
I draft brace positions on the sound board.
Cut and refine laminated upper transfers graft, I make 1/4 sawn laminated grafts here instead of one piece solid spruce as the laminations provide a stiffer brace without increasing cross-section area or thickness.
After glueing all grafts and finger braces in position, I carve the finger braces and tap tune the assembly. Glue lower V braces, upper transverse strut, upper cross brace, lower cross brace. I finish carving and tap tuning, then refine the completed sound board.

Once assembly of the soundbox is under way I’ll have the opportunity to tap tune the sound board after fitting the sides. The rigid perimeter provided by the sides reveals the true character of the top when tapping for tone. Full access is still available for any adjustments to the bracing and tone bars  and sound board thickness before I fit the back.

I dimension, thickness and refine book matched sides to a nominal 0.08inch/2mm.
The sides are shaped by hand on the hot iron following the soundboard template. In an open build this becomes far more challenging, as there is no mould and/or side spreaders to help the sides conform to the planned shape. The sides must finish exactly to the line throughout the curves, and stand exactly perpendicular to the building board. Otherwise unwanted forces are going to try to distort the body shape during assembly and cause all sorts of troubles.

 

 

 

 

The ultimate result of a successful bend is that everything sits together without any straining to fit. So no hidden stresses are left built-in to the guitar. The soundboard and back are relaxed until put under tension by the concert tuned strings.

Neck to sound board connection.

This is a crucial point in the construction of the guitar. The neck must align perfectly. The joint must have seamless contact throughout to ensure that resonances flow and so the joint endures. From here the build continues on the assembly board, the guitar will remain fixed down in position until the assembly of the complete sound box finishes with the back.

 

 

 

 

 

The neck/body angle is adjusted and the shelf accurately marked. I cut and refine to receive the soundboard precisely. Final alignment is made and the sound board/neck joint is glued up. Then the neck and soundboard assembly are set up on the assembly board for the sound box build, where all the pieces come together.

 

 

 

 

I cut and refine the mahogany tail block. Then align and glue in position on sound board. Sides are trimmed to fit into the heel and tail whilst following the plan exactly. Then I trim the heel block and side locking wedges to match and glue in the kerfed linings. Effectively joining sides to sound board. I form the side edges to the back arch profile using a large sanding board. In this case I’m aiming for 3/16 inch/4.75mm peak to the arch just behind the waist, where the lower bout springs out, coinciding with the no.2 cross brace of the back.

Back.
Similar procedure to the soundboard, thickness, refine and join. The centre seam will have a sapele stripe with b+w purflings either side to the walnut. Traditional arched cross bracing.

Refinement and assembly of the back to body joint. I glue  up and clamp body assembly by the age-old traditional method of roping. After a period or curing the guitar is released from the roping and clamps. For the first time the guitar shows off its true form. All points of the construction are scrupulously checked for quality of jointing and alignment.

 

 

 

 

 

Bindings and purflings, end graft. The end graft is sapele, matching the back centre stripe and bindings. The side purflings will mitre and border the end graft for completeness of the aesthetic. After cutting the stepped rebates to front and back, I select, laminate and refine the bindings. I bend on the hot iron to fit exactly in place without any forcing. Again when gluing I use the traditional assembly by roping. I form the sapele heel cap with matching black and white  veneers.

I select and refine the finger board blank, cut the fret slots and shape to final sound hole size and position at 19th fret. Alignment and glue onto neck. I carve  a compound radius as per design brief. Polish the playing surface. Install frets and refine.

Carve the neck.
I carve every neck and heel by hand. Every neck is either bespoke to the clients wishes, or follows a predetermined shape and taper that I have developed over time. In this case the client has provided me with neck profile templates at fret #1 and fret #9 as guides for his ideal. A wide, flattened oval profile is carved to match exactly.

 

 

 

 

 

 

 

 

The whole guitar is worked on, each area or component at a time, until a good pre-finish standard is achieved and all outstanding refinements are completed.

 

 

 

 

Finishing.
The request is for shellac french polish over tung/danish finishing oils. For this I like to split the finishing into the two stages. I can set the guitar up, i.e. saddle and nut, string intonation etc in between, after the curing time of the oils. This allows a couple of weeks for the guitar to sit “under observation” before set-up.

 

 

 

 

Set-up.
I double-check that the frets are all perfectly levelled and re-dressed. A final check of the fingerboard and I apply a special blend of oils to nourish the bare wood playing surface. I shape the saddle to calculated final string lengths that include for intonation compensation and the nut is shaped and string slots cut. After fitting of the tuners and strings, the action is measured and adjusted accordingly at the saddle and nut, and intonation of each string is checked again and adjusted during the process. The whole operation takes time and must be executed methodically.

Finally the proof is in the playing! I’m really pleased with the sound, very rich, warm, bright and very responsive and dynamic. Some delightful overtones and the fundamental is strong throughout. I keep the guitar strung at concert pitch and regularly play it for a couple of days to see/hear how the sound board settles in.

Later on, after the french polish process is finished, I’ll re-string the guitar and give it  some more playing over a couple of weeks before passing the finished guitar over to the client. I’ll post some pics of the completed guitar shortly, once finishing is, erm, finished. And hopefully a little video of the guitar in play..

Talking Of French Polish.

Traditional hand finishing to the highest standards can take as much time as the construction of the guitar itself. I usually start a new guitar build when the current one goes into the finishing room. As I hand build around 12 guitars each year, that equates to the 4 week build time plus 4 week finishing time that I usually quote to clients.

Endless bodying sessions with hundreds of passes applying micro fine additions (not layers) into the shellac, bodying up, spiriting off, rubbing back, levelling, polishing and burnishing to perfection takes time, effort and patience. There are no short-cuts to an immaculate french polish finish. The aim is for the highest quality finish with minimal thickness.

I’m working around to the sound board, I rubbed back the 3 spit coats of dark amber shellac with alcohol and FFFF pumiz powder. Then on with more dark amber, there’s been some filling around the bridge, the amber shellac has taken on a darker tone in that area. I like the effect, also some darkening around the perimeter, it’s given a little “age” to the finish. From here I’ll be using super blonde (basically clear) shellac. It’s looking good for some bodying sessions to build up a few microns in thickness ready for the polishing..

 

The first bodying session on the sound board went really well today. The super blonde shellac buffed to a good shine during spiriting off for a first session. There’s still a little work to concentrate on around the bridge, I’ll be paying some extra attention there during the coming sessions.

 

 

Nearly there. When I’m happy with all the details I let the finish gas out completely, curing takes a couple of weeks. I keep a close eye on all surfaces as the cure proceeds. When fully cured I fit new strings and play the guitar again The finish is so thin and light that the guitar’s vibrations aren’t restricted at all. Alma sounds as sweet as ever and is a delight to play.

 

 

Some pictures of the finished Alma Custom Classical Guitar