Going back to our theme covered in our previous post in which we told you about how we select the wood we use to build our guitars, today we will talk about the building process itself.
The Building Process
Not a single nail is used to build a guitar. All pieces are assembled using glue exclusively. Not all types of glue are suitable when building a guitar. Different types of glues are employed on different parts of the guitar depending on their properties as they set. Some types of glues conserve certain elasticity as they set, while others crystallize and form a more rigid bond. Keeping in mind that wood is a ‘living material’ that constantly interacts with its environment (in terms of temperature and relative humidity) certain types of glues are more convenient in certain parts of the guitar and less convenient in others. This strategic use of different types of glues while building a handmade guitar ensures its longer life and optimal vibration.
The next step is machine processing. The wood is machine cut in a specific manner especially devised for building of musical instruments. Each piece is calibrated to a desired thickness. We then proceed to joining of the two pieces that compose the harmonic top and the back. Following this step, we go on to assemble the guitar neck which is comprised of five elements, cut from the same wood piece configured in a very specific manner so as to best withstand the string pressure and achieve the desired angles of the headstock and the shape of the heel. We contour and polish the “slipper foot” (the inner bottom of the neck structure that joins the top, the back and the sides). Following this step the headstock is veneered with a thin piece of rosewood that will reinforce and decorate the face of the part of the guitar that houses the machine tuners or wooden pegs.
The elongated pieces of wood that will form the sides of the guitar are paired to match the pieces selected for the back of the guitar. Following this step we soak them and then bend them into the characteristic curvy shape using a curved iron device heated to 250º C. The curved sides are slipped into a mold in order to set into their definitive shape; we then join the bottom of the two sides using a Honduran cedar joint.
The next step is the preparation of the harmonic top and the back after calibrating its desired thickness. We proceed to inlay the rosette that decorates the sound hole. This is a very delicate process in itself since a rosette is really a dyed wood mosaic composed of thousands of pieces configured in a specific way so as to form geometric or figurative shapes. Creation of a guitar rosette is in itself an art of its own.
After inlaying the rosette we proceed to gluing the struts onto the inverse side of the harmonic top. The configuration of the struts and cross bars is a process very specific to each luthier. Apart from reinforcing the top, the struts help drive the vibrations inside the harmonic box and in this sense they are a very important part of the guitar building process. The cross bars force the top into a mildly convex shape.
Similarly the back of the guitar is prepared using cedar cross bars and strips that reinforce the body of the guitar as well as give the back a slightly convex shape as in the case of the top.
We join the top and the previously prepared neck; we then join the loose ends of the sides with the guitar heel joint. Following this we join the top with the sides using small spruce shins cut into triangular shape. They are tightly arranged and individually glued so as to form a strong union along the inner perimeter of the guitar. Reinforcements are glued to the sides and once the inner face of the top is dated and signed the harmonic box is closed using the previously prepared back lid.
Using a scratch (marking) gauge we precisely cut back the edges of the top and back side of the guitar in order to lay in the purflings/bindings that will decorate the guitar edges. Purflings are held in place with a tightly wrapped rope that ensures uniform adherence of the purflings to the perimeter of the guitar as the glue sets.
Once the bindings are in place, we move on to glue the fret board in place on the top side of the guitar neck. Before doing this, some guitar necks are additionally reinforced with a piece of ebony or carbon fiber lodged in the heart of the length of the neck. This helps us guarantee that that the guitar neck will remain straight as an arrow over time since the guitar strings exert quite a lot of pressure on it. A straight and stable guitar neck and fret board are essential in a high quality guitar and for correct tuning. This is why wood selection, cutting and building of the guitar neck and fret board are so important.
Once the fret board has been glued, we carry on by shaping the guitar ‘heel’ and we give final contours to the guitar neck. This process is fundamental for future playability of the guitar. The shape of the neck is often especially finished according to the specifications of the artist the guitar is being made for. Hand size and the manner of playing are important here.
Finally we finish the surface of the fret board, this will determine (amongst other things) the correct height of the action and correct tuning.
Very precise surface cuts are made on the fret board in order to lodge the frets which are glued and hammered into place. We’ tool’ the frets individually to give them their final shape; each fret should have such a curve so as to have only one point of contact with the string as pressure is applied on it, also the frets are sanded to a slight inclination to compensate for different gouge each string has, this will avoid any buzzing that may arise as a result of string oscillation.
After all these steps we are ready to sand the entire surface of the guitar with a series of fine grain sand papers in order to prepare the guitar for varnishing depending on the technique the client chooses.
Quality guitars can be varnished in shellac (French polish) or any high quality synthetic varnish. The latter technique is more durable, however many professionals prefer shellac because the final coat of this natural varnish is very thin, and many consider it better for the overall sound of the guitar. Shellac finishing is very traditional and it requires a highly specialized technician and is very labour intensive.
Once the guitar is varnished it is polished all over, with special attention to the fret board. We then create a nut and a bridge out of bone and we, put the tuners in place (machine or wooden pegs) and we string the guitar and adjust the action height. This set up is slightly different depending on weather the guitar is classical or flamenco. The action on a classical guitar is higher for clarity of tone, while it is slightly lower on a flamenco guitar for comfort and playability.
Finally the guitar is tuned and it is ready to be enjoyed!
All of the above described takes approximately about two to three months of full time work by a highly specialized artisan builder. It takes a lot of passion and love of the trade to create these guitars and it is so worth it when we hear the first accords of the instrument we all love so much.