What is Bisque in Pottery? - Basic Properties of Bisque In the process of producing a product, the clay passes through different stages and at one of these stages the clay is called ‘Bisque’. so what is ‘Bisque’ in pottery and why is it important? The bisque product is fired once but not glazed. Usually ceramic products are fired 2 times. The first firing is for ‘bisque’ firing and the second firing is for glazing. The bisque is hard and insoluble and cannot be recycled. The texture and porous structure of the bisque may vary depending on the clay you use.
What is Bisque Baking? Before baking the bisque, the clay must get rid of the water it contains. You can speed up this process by placing it in a warm place in the sun. Unfired pottery contains some moisture, which is called ‘Skin Hard Clay’. It then dries out enough to be called ‘Bone Dry’. unfired pottery is called ‘Raw Product’.
Bisküvi'nin Özellikleri After baking, the bisque, unlike the ‘raw product’, is hard and no longer soluble in water. Being porous means that the bisque will absorb water. How porous the bisque depends on several different factors. The primary factor is the type of clay. Some types of clay are more porous than others. For example, unglazed earthenware such as terracotta is much more porous and therefore much more absorbent. In contrast, some types of clay can become non-porous after firing and do not need to be glazed. Secondly, porosity depends on the temperature you use in the bisque firing. The higher the temperature of the bisque fire, the less porous the ceramics will be. This is because as the temperature increases, the clay particles bind more tightly together and the pores in the clay begin to close.
Differences between Raw Product and Bisque in the Pottery World In pottery, the words raw product and bisque are often heard, but it is important to know what these terms mean and the main differences between them. Here is a compilation of the differences between raw product and bisque: What is Raw Product? The raw product is the shaped form of the clay and has not yet been fired. In other words, although it takes the form desired by the potter, at this stage the clay has not yet undergone the first firing process. The raw product has also been dried to the bone dry stage, but still contains some moisture. Therefore, when it comes into contact with water, it can become soft clay again. The raw product is characterised by its ability to absorb water and must be carefully handled. What is a Bisque? Bisquet is the raw product after the first baking process. In this process, the raw product is placed in the kiln and the clay undergoes physical and chemical changes. In the kiln process, the moisture in the clay evaporates, organic matter burns, chemically bound water is separated and bonds are formed between the particles by sintering. In the vitrification stage, the components in the clay mixture melt to form liquid glass. This process causes the clay to harden permanently and its shape becomes unalterable. An important feature of bisque is that the glass layer formed during the first firing process makes the ceramic product non-porous. Most bisque ceramics, however, are semi-glazed and still porous. Cooking Process and Importance The bisqueisation of the raw product involves a long process. The first baking process, which usually takes 8 to 10 hours, allows the clay to undergo the changes described above and not be damaged. A rapid bisque baking process can increase the risk of the clay cracking or bursting, especially if there is still moisture in it. These fundamental differences between raw product and bisque play a critical role in determining the quality and durability of products in ceramic art. Artists should carefully master these stages and shape their designs in accordance with these processes.
The Art of Bisque Baking A specific step in pottery making, the firing of the clay, is known as ‘Bisque firing’, a special process. This art becomes an adventure in which potters need a carefully planned firing programme. Here are the stages of this special process: Cooking Programme: Clay Timetable bisque firing takes place over a certain period of time at a certain temperature to burn the moisture and carbon in the clay. This process is based on a timetable, which we call a ‘firing programme’. This schedule ensures that the moisture and other residues in the clay are burnt off effectively, while at the same time preventing cracking or bursting in the kiln. Kneading and Compaction: Preparation of Clay In order to remove air bubbles from the clay and improve its consistency, potters process the clay through a process called ‘kneading’ or ‘compacting’. This is similar to kneading bread, but the goal is the opposite. Air bubbles are removed and the clay has a homogenous consistency. Three Different Ramps: Low, Medium and High The bisque baking process consists of three main ramps: low, medium and high. The low ramp is designed to remove moisture and dry the clay. The middle ramp allows the clay to heat up slowly and brings the kiln to red temperature before the high ramp starts. The high ramp is the final stage where the clay is transformed into bisques. Cooling and Waiting Time: Final Touches of Clay After the bisque baking is completed, the oven is left to cool. This takes the same amount of time as the baking time. As the kiln cools, the clay becomes completely bisqueised. In some cases, a ‘waiting time’ is added to completely burn off the carbons. The process of baking bisque requires preparation, care and patience. However, the results are beautiful and durable artefacts. This long-term process reveals the essence of pottery art and the subtleties of its craft. These basic steps in bisque firing ensure that each piece is unique and offer the artist many creative possibilities.
bisque Glazing bisque Oven and Alternatives In the art of pottery, the bisque kiln is a critical step that enables the clay to acquire important properties. This process contributes to hardening the clay, making it durable and resistant to water. Another important factor is that the bisque kiln prepares the artefacts for glazing. However, not all bisque fired clay needs to be glazed. For some situations, the porous characteristic is useful. For example, terracotta pots. Likewise, porcelain stoneware can become 100 per cent non-porous in the first firing, so it may not be necessary to glaze it completely. The porosity of some bisque fired clay provides an excellent surface for glazing. Because bisque is porous, it absorbs water in a liquid glazing mixture. The glaze then adheres to the clay. Different levels of porosity will require the application of different types of glaze. For example, less porous bisque ceramic should be glazed with a glaze with a lower water content, as less water will be absorbed on application. Single Firing Glazing attracts attention as an alternative. Some artists prefer to glaze directly onto unfired clay or green ceramic without bisque firing. This is known as single firing or raw glazing. In order to glaze over clay, the clay must be completely dry when the glaze is applied and the glaze must have a high clay content. The high clay content in the glaze reduces the likelihood of the glaze flaking off during the firing process. However, one disadvantage of single firing glazing is that ceramics have a higher chance of cracking or bursting in the kiln. Although making a bisque kiln requires patience, there is a better chance that your ceramics will have more integrity at the end of the process.