The Model is the starting point for any production. We can use a physical piece, a prototype or a simple drawing. The model is the representation of a need in the way that it gives us all the references need about the product.
The 2D or 3D drawing can be considered one type of model. Using the technical drawing of various views, it is possible to develop a new product, however, it will be always needed a prototype that can be done by hand, 3D Printing or by using another type of technology.
Even knowing that majorly the prototype is always associated to a drawing, sometimes the prototype can be made by performing small changes on an existing product. On the other hand, the concept can emerge from a practical process, such as the craftmanship.
The model can sometimes come from a physical sample. Usually, this method is used when we want to replicate an existing object.
The Master is a piece produced based on the model, which serves as the starting point to create the mold. Knowing that during the firing process the clay suffer a retraction, the Master needs to be bigger in scale compared to the original model. Depending on the type of conformation the Mother can be composed by clay, plastic, metal or porous resin.
Being indispensable for the conformation process, depending on the technology used in the production, this tool can be composed by clay, porous resin or steel. Some of these techniques, such as the roller, requires the use of clay molds, but also a steel countermold.
Plaster is some of the main materials used in mold production. Most used on casting technique due to his high porosity and absorption capacity, yet, we can also see his utilization on another technologies.
Some polymeric compounds, also known by porous resin, are frequently used on mold Production due to its resistance and hardness. This molds show us a high durability and precision that allows us to shape the porcelain paste with less water. As we see in the case of the high-pressure casting method.
Although not being used so much as plaster or resin, metal continues to be an important material to develop tools of conformation. It happens on the roller, where we use a plaster mold but also a metallic contermold that is used to shape the inner side of the piece.
Inside the various types of casting, in Bemorporce the are used 3 technologies to shape our products. The High-Pressure casting, The Roller and slip casting casting.
This technology is used mainly on plate shaping, trays and also bowls. The mechanical resistance of the molds allied to the pressure exerted on the porcelain paste allows us to get a perfect shape but also a good resistance on the pieces produces by this method.
The roller technique is based on a vase rotation due a mechanical process. By pouring some porcelain paste inside a plaster vase, we use a metallic piece that spreads the ceramic paste thought the inner surface of the vase expelling all the excess material. This technique is used to produce cups, bowls and some other objects.
The slip casting technique continues to be an excellent option for producing porcelain. This technique consists on filling a plaster mold with slip porcelain. After a few minutes, this liquid porcelain sticks to the plaster and the water starts to be absorbed by the plaster.
After the conformation process, the pieces are moved to special environment that allows them to dry the remaining water inside the porcelain. During this process the porcelain gains a different texture and gets lighter in weight. We call this state “chacote” or Green Porcelain.
After being drained, the pieces are submitted to a first fire. Here, the chacote goes into a high temperature fire reaching 1100ºC for a few hours. During this process, the porcelain suffers retraction that results from the fusion of the material that composes the ceramic paste. After this stage, the chacote come to be called bisque or biscuit.
It can be white, coloured, but also black and Black matte our even reactive glaze. The glazing technique is a process consists on creating a thick coat of glass particles all around the piece.
One of the techniques used in glazing is the curtain technique. This automatic method consists of making the pieces move on an automatic treadmill, where these pieces pass through an aqueous solution of glass particles that is poured over them resembling a curtain.
By using the dipping technique, as the name suggests, the porcelain body is merged under an aqueous solution of glass particles that forms a coat all around the piece.
The Paint Spray Gun, or pulverization technique is a method where the pieces are glazed using an air compressed gun that pulverizes the piece with a mix of glass particles and water. The method is used to glaze bicolour pieces.
In addition to the 1st firing process, which results the biscuit. The pieces are summited to a second fire. This second stage is used to finish the porcelain pieces with a smooth glaze. The glass particles stick to the surface of the biscuit when being exposed to a high temperature fire. These particles start to melt, covering the object with solid glass.
We can obtain a different range of white glaze depending on the atmosphere that we fire the glass. By using that technique which is called oxidation, we can turn the white glaze into beige.
The colour finishing’s are the result of the reaction of some particles that are added to the glass solution. These particles when exposed to the high temperatures of the second fire start to react. This reaction enhances the colour of the pigment.
After the pieces being finished, there is also the possibility to customize them.
One of the most used techniques is the decal. This allows us to use mass produced decals that allows us to decorate a large number of pieces with the same artwork.
During this process we use a rubber stamp, when pressed to a inked metallic sheet, this stamp is transferred to the printing surface, stamping the piece.
This technique is used to apply backstamps
By rotating the piece with a mechanical movement, the pieces are painted by a fixed point. This technology is used to decorate cups, bowls or plates.
The third fire is the final stage to finish the product. Although the pieces are finished after the second fire, this third heating is used to finish the decoration process. On this last stage we don’t use such a high temperature as we use on the previous baking’s, however, on this final fire the heat should not increase more than 850ºC