To date, the production of porcelain chess sets uses all the achievements of centuries of experience in the creation of porcelain products and finds of artistic skill. Manufacturers of collectible porcelain sculptures strive to make every item that comes out of their workshops a work of art. Quality control is continuous – from the model development stage and throughout the production process, which can take several months, from the moment when the initial sketch comes out from under the artist’s pencil, and until its final destination – the hands of the collector.
It takes about a year and a half to create one luxury chess set made from porcelain. Ideas and relevance of topics can come from situations in the world or some events. For several months, information is collected about the event itself, its participants, and costumes.
At first, a rough clay mold is created. Gradually cutting off the clay from it in tiny pieces, the final version of the form is created. A gypsum model, from which a porcelain chess piece will subsequently be made, is created based on the first form.
A gypsum mold must be used because the gypsum absorbs water, leaving only the porcelain itself in the mold, as the porcelain is stirred with water to give it a liquid appearance. The gypsum is used in the creation of the model is thoroughly cleaned to achieve the highest fine dispersion in order to most smoothly reproduce all the details of the product. Water and gypsum powder are mixed together, while in order to prevent the formation of air bubbles in the mixture, it is mixed with a vacuum blender. A matrix is created from the liquefied gypsum, based on which a working model is made. After removing the gypsum mold from the model, the mold must dry. It is desirable in a natural way that everything dries evenly, as this affects the ability of the gypsum to absorb water in the future.
In private workshops that value the individual approach to their customers and the quality of their products, molds are used about 10 times, after which they are updated. The newer the form, the less handwork with the casting. It is believed that porcelain does not like to be touched at the manufacturing stage, the less touching, and the better. Therefore, ideally, the form should be of such quality and condition that when you take out the casting, you remove the seam – and everything will be ready. But this, of course, is in ideal theory; it takes a lot and a long time to process.
During the time that the models are drying, porcelain clay is being prepared. Clay is mixed with water in the same way to form a solution called slip. The slip resembles a thick paste, usually different in color from the final color of the product, since the clay changes color during the firing process. After the gypsum mold has dried (from 3 to 7 days), slip is poured into it. The longer the slip is in the mold before the mold is poured out back, the thicker the wall of the product will be. The model filled with slip is left for 30 minutes; at this time, the gypsum absorbs the liquid from the clay. After this time, clay particles remain on the surface of the model, thin enough to make products from them. The slip remaining in the middle of the product is removed.
Too thin walls – elegant, there is a feeling of lightness, but at the same time, with thin products you need to be careful not to push through, not to wrinkle during processing. But there are also pluses, the probability of its tilting in the kiln during firing decreases, since porcelain becomes plastic at high temperatures, and if the casting is heavy, the weight is distributed incorrectly, it can tilt.
The model is again kept for some time so that the impression of the product can be carefully removed from it by gentle tapping. At this stage, the products still have some plasticity.
At the stage called final processing, all small seams and roughness are carefully removed from the workpiece, and artistic features are added. The master tries to process in a short time, as the workpiece begins to dry immediately after contact with air.
The figurine is then air-dried to evaporate the moisture before being fired. Any residual moisture in the porcelain will cause it to crack during the firing process.
Casted products are fired in kilns. The first firing takes place in a gas furnace at 2,300° F (1,260° C) for 14 hours. During the first firing, the workpiece also changes its color, which acquires the originally intended shade. Any impurities in the clay during the firing process will lead to a loss of color, and the product will have to be sent to the scrap. During firing, glass transition occurs, leading to a change in the color and structure of the clay. A porcelain chess piece can give shrinking within 15%.
If the surface of the product needs to be sanded to give a satin sheen, then the next stage of processing will be polishing. Polishing has another additional advantage, namely, that we get a perfectly smooth surface, which will allow us to fully reveal the skill of the decorator.
The highest level of training is required from decorators, not only in terms of painting technique, but also in the ability to capture the very spirit of the figurine.
Before being sent for secondary firing, the figurine is inspected for the accuracy of the embodiment of the idea and compliance with all requirements of the production technology. Unglazed items are polished, painted and fired again. For secondary (or decorative) firing, electric tunnel kilns are used, during which the paints are firmly fixed on the surface of the porcelain. In the case of glazed porcelain, a third or even fourth firing is used (to fix the glaze or relief decor). In the decorative firing process, the figurines are fired for 4 hours at about 1,300° F (704.4° C).
In the creation of highly artistic collectible porcelain chess, constant quality control is of paramount importance. All materials, especially gypsum and clay, are carefully selected, processed, mixed and used with the utmost care. If impurities remain in the china clay, then because of firing, the perfectly white ornament will turn bright pink, and the entire product will have to be rejected. Products undergo six or more quality checks before being shipped to the customer. Air-dried blanks are inspected.
After firing, the product is again checked for pores and cracks. After polishing, another detailed inspection follows. Then – immediately after applying the decor and, finally, at the end of the secondary firing, to verify the correctness of the resulting color. If individual flaws in the decoration are found, the product is sent for drawing or re-firing. However, significant errors mean writing off a porcelain chess piece in reject.