The simplest ceramic oven used for Easter Limoges Boxes consisted of a lower part (also called cinerary), intended to house the fuel, and an upper cooking chamber which the fire, arising had to pass through, filtering through numerous open holes in the floor.
The biscuit, due to its porosity, rapidly absorbs the most liquid part of the compound, leaving the metal parts on the surface. In the case of majolica, once dried, the ceramic dipped in the enamel can be decorated, painting it or superficially scratching the colored parts.
The most advanced oven has the addition of a third environment located above the main cooking chamber. Being in proximity to the chimney for venting the flames, the residues of the combustion (smoke and soot) were concentrated here: this, therefore, was the cooking chamber destined to the biscuit, which could not be damaged by these residues being devoid of melt coatings.
Another type of furnace was the so called muffle furnace, in which the flames passed through an external interspace, without touching the objects to be cooked.
The muffle furnace could also become a furnace with a reducing atmosphere, when oxygen was removed from inside the cooking chamber.
This operation was usually carried out by introducing substances which, when heated, produced abundant fumigation. Cooked a third time (third fire) at a modest temperature (around 650 ° C), the colors used in the decoration become iridescent and take on metallic reflections.
The cooking phase of the artefacts was a particularly delicate operation, to which particularly expert people called kilnsmen dedicated themselves. To make the most of the fuel, they tried to fill the furnace with as many objects as possible, placing them on top of each other in ordered piles (stacking) for Easter Limoges Boxes.
The artefacts with siliceous-metallic coating (enamelled or glazed) were spaced with special supports, which very often assumed, as still today, the shape of the tripod, in order to prevent the fusion of the coating from welding them together during cooking.
In traditional ovens (not in muffle types) to prevent the flames and other residues of combustion (dust, soot, dust) from damaging the enamels or windows, the artifacts were prepared to be cooked in special containers, called boxes or boxes, inside which they were spaced by small triangular supports inserted in the walls and projecting towards the inside of the boxes themselves.
Once filled, the furnace was sealed by closing the access door to the cooking chamber with a temporary wall: thus, the fire was forced to vent outwards through it completely.
The firing of the furnace involved in the first phase the use of small-sized wood (stipa) which burned easily and evenly, rapidly bringing the cooking chamber to the desired temperature.
