Manufacturing techniques

Transformation of clay into ceramics: preparation
In Salernes, the extraction of clay has always been easy because the top-quality ore is found in huge amounts, practically at the surface. Nowadays, four quarries are in operation; reserves of clay will last for many more centuries to come!
The technique for preparing the clay has not changed. Naturally, the délavoirs, used to remove the water, and the evaporation basins have been replaced by déliteurs, to the cut the ore, and press filters. But whether it is found in the specialized GIE factory or in the more modest individual workshops, the modern extruder produces large quantities of degassed choice raw material.


The shape: crafting

The clay "bars" are delivered and/or produced every day upon request. The work can now begin. In the workshops, magic is about to happen...
Each craftsman puts his skill, passion, persistence and personal research into the service of the clay to obtain a completely different finished product.
Whether the clay bar is stamped, moulded in plaster or in a frame, whether it is cut out using a template or a punch, mechanized or not, it is the hand of the craftsman and the dexterity of the operator which determine the final result.
The ceramist often uses his fingers to craft the clay and smoothes it out by pressing it onto a marble block. The tiles are then arranged in piles or on racks for drying.


The material: drying and firing

Drying, which can be either a natural process or speeded up by ventilation and/or heat, evacuates nearly all the water used in crafting. The greater the size and the more complex the shape, the more delicate and lengthy is the drying process.
Firing is a decisive step in the manufacturing process. Naturally, it determines the mechanical properties of the product as well as, in the case of non-enamelled terra cotta, its aesthetic qualities. According to the temperature and the atmosphere of the firing, the colour varies from deep brick red to red or yellow ochre, or pinker hues and even cream.
For reduction firing (combustion with less air, changing the colour of the clay), the disposition of the tiles in the oven determines the variations in colour: flamed when the firing is arranged edgewise - with a trim, when fired in piles.
For the two enterprises which still fire using wood, the lengthy combustion of the larch wood gives "flaming", a random mixture of various shades of colour.


The colour: enamelling and decoration

Enamelling consists of coating the terra cotta tile, called the "bisque" with one or more layers of coloured, finely ground glass. The enamel is first put in a watery suspension and then spread over the tiles. The bisque absorbs the water and the enamel settles on the surface of the tile; depending on the type of rendering required, enamelling is carried out by spraying, by hand (using a pistol) or partially mechanized, with a bell, a ladle or by dipping. The temperature of the firing, between 950 and 1000°, results in an infinity of colours and nuances.
Most of the time, a brush is used to decorate the tile, on bare enamel by using metallic oxides which are pure or mixed with glass "colours to paint". The decoration and the enamel are thus fired in a single firing.
However, depending on the type of decoration, additional techniques may be used: stencils, serigraphy by hand, insertions, engraving, etc.
It is sometimes necessary to carry out several successive firings, at different temperatures, to obtain the required result.


Lava, a diversity of shapes and appearance

Lave is a volcanic substance produced from magma and it is found in the form of natural rock. It is extracted and sliced up in the quarries and then cut up, crafted and enamelled according to the customer’s requirements. Lava is special because it does not lose its mechanical properties when it is fired; it thus offers a range of possibilities with regard to shapes and technical or artistic cutting which is normally found in marble, basalt or granite.
Lava is also a material which does not freeze which means that it can be used for outside surfaces which may be subject to extreme weather conditions.
Without pointing, an enamelled lava counter is ideal near water or a cooking area. Various types of drilling, machine edging, imprinted and grooved surfaces, or any other type of crafting is carried out for the finishing.
Depending on the final appearance requested, the ceramist carries out all or some of the following operations on each slab: sanding, filling in the natural porosity of the lava with a filler, flat or intaglio sanding. The lava is then fired a first time to stabilize the filler.
This is when the enameller takes over. The various enamels are spread in successive layers. Once again, depending on the colour or the effect required, we obtain either a single enamel or an undercoat of white enamel and then a transparent coloured enamel.


Bulk items: pottery and accessories

In addition to the production of the flat items described beforehand, the ceramists also produce more bulky items: crockery, basins, tians, soap-dishes, balusters, furniture, etc.
Only the crafting techniques change: turning, gauging, embossing or imprinted stamping, pouring a barbotine in a plaster mould (in this case, other clays must be used as Salernes is not suitable for this technique); all these processes are used to obtain the required shape.
Once drying and firing have taken place, the same techniques of enamelling and decoration give the products their character, as single pieces or with other items produced in Salernes.