How is a sculpture made?
Development of a Sculpture
From a Small Blob of clay!
The excitement of starting a work is always electric. The sitter arrives with clay and tools already having been prepared. The studio is warm and coffee aroma fills the air. The work starts organically from scratch as a small blob of clay, held in place by a wooden frame (armature).
The first sitting. Callipers are used to take accurate measurements. These are written down so that they needn′t be repeated. Conversation flows as the work progresses dispersed by the scratch of felt–tip pen upon paper in contrast to the silence of the clay being modelled.
Angles are established between measured points, which create a 3–D grid of points in space. "Bar–codes" through key points give the fundamental proportions. This enables the profile to be found very accurately, this in itself creates a good likeness.
By the end of the first sitting we have become aquatinted and the work has begun to take on a rough appearance of the outer form of the head. Not yet a sculpture, but a form infused with a measured understanding. Many are surprised at what can be seen in the work, even at this early stage.
Each work develops according to it′s own rhythm and timing. Some demanding more sittings than originally intended, but most within the guidelines set out. The progress of the work follows a strict protocol that ensures it′s constuction is accurate.(to save your sitting time!)
Each piece of clay added corresponds to a sculptural question that I ask. These can range from formal considerations such as measurement to more abstract qualities such as surface quality and tone that give character.
The act of seeing and drawing is essentially a reflex arc. The image falls onto my eye. From the retina it travels directly to my hand, of which the pencil is the extension. I let it travel through what I happen to be, but without interference. I don′t allow the interpretive machinery of the brain to take hold of it, to label it quickly, a beautiful tree or a poplar.
The pencil in my hand becomes like a seismographic needle, registering the inner tremors of my seeing.
Frederick Frank — Art as a Way
The second sitting isn’t such a mystery since the work has already begun. The flavour of the next 4 sittings has been established and the conversation can develop alongside the progress of the work. There may be minutes that go by in silence, giving both sitter and artist time for personal contemplation. This may be broken in order to focus upon a certain expression that isn’t apparent during quiet moments.
From 2 fixed points measurements are taken towards the tip of the nose, the bridge of the nose, chin etc. This allows the profile to be accurately understood. All measurements, especially the angle at which the head and face sit on the neck are established before further developments. Lines can be drawn that help to establish the basic planes of the brow and nose and how these project.
Working from the front, the central line of the eyes is established together with the bottom of the nose and mouth. It is ensured that the relationship between these lines is accurate before proceeding. The width of the eyes, nose and mouth are measured and marked in the clay.
The second sitting will be used to observe the curved lines that travel around the head. This helps to accurately fill out the volume and to make the connection between each part of the head, so that each part contributes towards the whole, rather than existing in isolation. This is still a technical stage and the "poetry" of the work is yet to be born.
Eventually the surface is understood in all 3 planes simultaneously. The modelling tool twists and turns with the wrist to follow contours, so that all forms are harmonised into one.
The third and fourth sittings take on a different quality. The structure has been found. The perception of tonal quality and expression is the next stage together with work on the features of the face. These are placed lightly into the measurements that have been previously been established.
Completion of the Clay
When the features are accurately sited, I am able to work on their appearance, which is achieved by very accurately capturing the visual perception of the sitter. At this stage I am not looking to reproduce exactly the same physical shape as the sitter, but rather to make very minimal adjustments in form that can take account of how the eye prioritises what it sees. The clay can be hollowed in a way that gives tones and shadows and literally "paints" the appearance of the sitter with light. By this stage in the proceedings we are becoming further familiarised and character can now be instilled into the work.
The clay is now complete with both the client and myself approving it for progression to the next stage. Now the work is signed.
Casting
Lost-wax Bronze casting has its roots in antiquity, yet has not changed that much in thousands of years. Sometimes called by the French name of "cire perdue", it differs from "cold casting", which is a resin infused with bronze powder. However, if in the hands of skilled craftsperson the results can barely bedistinguishable.
The stages of casting
Mould making. A two part mould is made of the clay so that each half can be filled with wax and put back together accurately. To preserve the fine details of the clay’s surface, an inner slicon mould is painted onto the clay. This is supported by the outer plaster case of the mould.
Wax. Molten wax is painted and then poured into the mould to give an even coating 6mm—8mm thick.
Removal of wax. This hollow wax copy of the artwork is removed from the mould.
Touching up the Wax. The hollow wax copy is then "dressed" to hide any imperfections including the seam line. A wax "foot" is added so that it can be attached to a base. The signature plus edition number with date are etched into the wax. The wax now looks like the finished bronze in every detail. A separate wax is required for each bronze edition to be cast from the mould.
Spruing. The wax copy is "sprued" with a tree–like structure of wax that will eventually provide paths for molten bronze to flow and air to escape. The carefully planned spruing usually begins at the top with a wax "cup", which is attached by wax cylinders to various points on the wax copy.
Investment. The "sprued" wax is covered in a mixture of plaster and crushed ceramic (investment). The process is repeated until a coating of 10cm covers the entire piece.
Burnout. The invested wax is placed cup–down in a kiln for at least 36 hours. The melted wax can be recovered and reused, although often it is simply burned up, hence the term "cire perdue" (lost wax). Now all that remains of the origial wax is the negative space that it once occupied within the investment material. The feeder and vent tubes and cup are also hollow.
Pouring the Bronze. The investment is placed cup–upwards into a tub filled with sand. Bronze is melted in a crucible in a furnace to 1200 degrees C, then poured carefully into the investment. The bronze–filled investment is allowed to cool and can be opened with half an hour of pouring.
Release. The investment material is hammered away, releasing the rough bronze. Now one can see if the casting is successful and at this stage it is customary to open a bottle!
Metal-chasing. The spruing tubes, which are also faithfully recreated in metal, are cut off, to be reused in another casting. The bronze is worked until the telltale signs of casting are removed, and the sculpture again looks like the original artwork. Pits left by air bubbles in the molten bronze are filled, and the stubs of spruing filed down and polished. The foot of the bronze is levelled and drilled, ready for the base.
Patinating. The bronze is now ready for colouring (patination). This is an age–old technique that mimics the patina′s of ancient bronzes and many foudries keep their recipies under lock and key! I prefer to use hot patination which gives me a very stable and even coulour. The bronze is heated with a blow torch and acids stippled onto the surface to oxidise the metal. After the patina is applied, a very light coating of pure bees wax seals and protects the bronze.
Base. The bronze is firmly secured to a marble or wooden base that has been made for the unique sculpture. The sculpture is finished and ready for delivery with an authentication certificate.
