Vitrification point
The vitrification point marks a critical stage in the firing of ceramics, in which the components of the clay (clays, feldspars, silica, among others) begin to melt and join together to form a continuous vitreous matrix. In this process, the piece ceases to be porous and acquires characteristics such as greater hardness, structural stability and resistance to liquid filtration.
The temperature range at which this change occurs depends on the composition of the clay and the type of ceramic to be produced, since the different families (earthenware, stoneware, porcelain) have specific vitrification temperatures. In addition, the shape and size of the pieces, as well as the atmosphere and the soak time in the kiln, can influence how and when this point is reached. Precisely controlling the vitrification phase is essential to obtain final products with the desired physical and aesthetic properties.
Before the systematic domestication of kiln temperature, some cultures used subtle cues, such as the color of the fire or the deformation of ceramic cones, to sense the degree of vitrification. These empirical methods were passed down from master to apprentice, constituting part of the traditional knowledge in various regions.Interesting Fact
During the Middle Ages, European potters accidentally discovered how to control it while experimenting with new clay mixtures and firing temperatures. This breakthrough led to the creation of more durable and water-resistant pieces, which revolutionized the manufacture of ceramic utensils and contributed to the development of glazed earthenware, essential for the safe storage of food and liquids.Helpful Tip
Document firing curves and the results obtained in each kiln firing. With this information, you will be able to fine-tune the temperature and time needed to achieve the exact vitrification, reducing losses and defects in production.