Topic outline

• Ceramic Handbook
  What is Ceramic Handbook?
  

  
  

  Ceramic Handbook is an open online resource for students, teachers, artists, and designers working with ceramic materials. The goal is to provide accessible information, instruction, and inspiration for studio learning in ceramics and to support alumni and life-wide learners in their design and art projects with ceramic materials.

  The handbook is developed at Aalto University, School of Arts, Design and Architecture, Finland. The venture is a joint effort between the teachers, researchers, studio personnel, students, and alumni in the Department of Art, Department of Design, and Aalto Ceramic Studio. The development of the Ceramic Handbook was funded by Aalto University's A!OLE, Aalto Online Learning project.

  The Ceramic Handbook is under development and in the testing phase. 
  Please provide feedback if you find anything to improve in the material. Let us develop the material further as a collective effort.
  Thank you for your feedback!
  

  Read more:

  Introduction

  Table of Contents

  
  

• Introduction
  What is Ceramic Handbook?

  
  

  Ceramic Handbook is an open online resource for students, teachers, artists, and designers working with ceramic materials. The goal is to provide an accessible information, instruction, and inspiration for studio learning in ceramics, and to support alumni and life wide learners in their design and art projects with ceramic materials.

  The handbook is developed in Aalto University, School of Arts, Design and Architecture, Finland. The venture is a joint effort between the teachers, researchers, studio personnel, students, and alumni in the Department of Art, Department of Design and Aalto Ceramic Studio. The handbook includes textual information, illustrations, animations, and videos to deliver the learning content. The site also highlights projects and current research conducted in Aalto University. The development of the Ceramic Handbook was funded by the Aalto University's A!OLE, Aalto Online Learning project.

   

  Who is the Ceramic Handbook for?

  
  

  The Ceramic Handbook serves as a teaching material both in basic and advanced level. It is developed to be an open educational source for various pedagogical approaches in different levels of education and can be applied in many ways.

  It gives the basic information of the materials and techniques and elaborates those towards advanced level with more detailed information, artist demonstrations and interviews, academic research, and project examples - to inspire learners' creativity and individual approaches in how to use the material for design and artistic work.

   

  How to use Ceramic Handbook?

  
  

  Ceramic handbook is designed in a way that it allows you to start in any section and browse through the material. The basics are in the Aalto Open Learning site directly, and the advanced material is in the pdfs at the end of each section. You can get started by browsing the Table of Contents.

   

  Disclaimer and Feedback

   

  It is important for the reader to note that few things in the management of materials and techniques are absolute truths. It is in the nature of design and art that everything is suitable to try, to combine materials and techniques, and to develop new techniques. Experimental approach and curiosity open up new paths.
  
  When working with ceramic materials, it is important always to follow good studio practices and the safety instructions given by the manufacturer and the importer.
  
  The Ceramic Handbook is under development, and in a testing phase. Please provide feedback if you find anything to improve in the material. Let us develop the material further as a collective effort. Thank you for your feedback!

   

  Working group

   

  Jaana Brinck, Department of Art
  Tomi Pelkonen, Aalto Infra, Ceramic studio
  Nathalie Lautenbacher, Department of Design
  Eeva Jokinen, Department of Design
  Priska Falin, Department of Design
  Saija Halko, Ceramist, Designer
  Mimi McPartlan, Ceramist, Designer 
  Aura Latva-Somppi, Department of Design
  Karen Visuri, IDBM Master’s programme

  Illustrations and animations: Nikolo Kerimov
  Photo credits in references

  Graphic design: Erin Turkoglu and Camilo Cortes

  Special thanks to Aalto Online learning/Yulia Guseva
  and Aalto Studios/Iikkamatti Hauru

  Aalto University, School of Arts, Design and Architecture
  Finland 2021

  
  

  
  

  
  

  
  

  
  

• Table of Contents
  
  

  
  

  CERAMIC MATERIALS

  
  

  1. Clay

  1.1 Different Clay Bodies and Plasticity 

  1.1.1 Plastic clay 

  1.1.2 Casting-slip 

  1.2 Raw materials in ceramic production 

  1.2.1 Plastic raw materials 

  1.2.2 Non-plastic raw materials 

  
  

  2. Ceramics 

  2.1 Grouping of ceramics 

  
  

  3. Glaze 

  3.1 Raw materials used in the glaze 

  3.2 Properties of glazes 

  3.3 Glaze-making 

  3.4 Glazing techniques 

  3.5 Ceramic clay-based coatings 

  3.6 Glazing at different stages of production 

  
  

  4. Ceramic colors 

  4.1 Metal oxides 

  4.2 Colored stains 

  
  

  5. Chemistry of ceramics 

  5.1 Classification of oxides 

  5.2 Empirical formula 

  5.3 Making your own glaze test kit 

  
  

  + Extra material pdf - Ceramic Materials, Aalto 2021
  

  
  

  
  

  
  

  FROM CLAY TO CERAMICS AND CERAMIC FIRING

  
  

  1. Changes in ceramics caused by firing 
  2. Progression of firing in stages 

  2.1 Measurement of firing temperature 

  
  

  3. Bisque firing and glazing firing 

  
  

  4. Different firing methods 

  4.1. Firing Atmospheres 
  4.2 Firing Methods 

  
  

  + Extra material pdf - From Clay to Ceramics, Aalto 2021
  

  
  

  
  

  
  

  CERAMIC TECHNIQUES

  
  

  1. Hand-building 

  1.1 Coiling technique 

  1.2 Slab-building technique 

  
  

  2. Small series 

  2.1 Wheel Throwing 

  2.2 Pressing 

  2.3 Jiggering 

  2.4 Slip-casting 

  
  

  3. Industrial 

  3.1 Slip-casting 

  3.2 Jiggering 

  3.3 Compression 

  
  

  4. 3D printing techniques

  
  

  5. Mold techniques

  5.1 Mold-making

  
  

  + Extra material pdf - Ceramic Techniques, Aalto 2021
  

  
  

  
  

  
  

  STUDIO PRACTICES AND EQUIPMENT

  
  

  1. Kilns and firing pg

  1.1 Electric kiln firing 

  1.2 Kiln programming and loading 

  1.2.1 Kiln loading structure and safety 

  1.2.2 Pyrometric cones 

  1.3 Important stages of firing and temperatures 

  1.3.1 Quartz inversion 

  1.3.2 Cristobalite 

  1.3.3 Dunting or cooling cracks 

  1.4 Different types of kilns and atmospheric firings 

  1.4.1 Gas 14

  1.4.2 Atmospheric firing 

  1.4.3 Wood 

  
  

  2. Other equipment and tools 

  2.1 Clay preparation and production 

  2.1.1 Pug mill 

  2.1.2 Extruder 

  2.1.3 Slab roller 

  2.1.4 Pottery wheel 

  2.1.5 Slip-mixer 

  2.1.6 Jigger 

  2.2 Glaze preparation and glazing equipment 

  2.2.1 Spray booth 

  2.2.2 Ball mill 

  2.3 Plaster modeling 

  2.3.1 Plaster wheel 

  2.3.2 Plaster lathe 

  
  

  3. Health and Safety 

  3.1 Kilns 

  3.1.1 Heat and PPE (personal protection equipment) 

  3.1.2 Hazardous kiln gases 

  3.2 Interview with Keracomp 

  3.3 Clay and glazes - dust, food-safety, and hazardous materials

  3.3.1 Dust and healthy studio practices 

  3.3.2 Food safety 

  3.3.3 M/SDS safety sheets 

  3.4 Plaster 

  3.5 Studio equipment 

  
  

  4. Recycling material 

  4.1 Recycling clay 

  4.2 Recycling glaze 

  
  

  + Extra material pdf - Studio practices, Aalto 2021
  

  
  STUDENT PROJECTS IN AALTO UNIVERSITY

  
  

  ART AND RESEARCH IN CERAMICS

  
  

  
  

  
  

• Ceramic Materials
  

  
  

  Clay

  
  

  Clay is a flexible and tough material that can be formed using many different techniques. Moist and soft clay becomes hard and brittle as it dries, and when fired it hardens and condenses into a very durable material, i.e. ceramics. Clay materials are the oldest construction materials developed by humans from natural raw materials and, as such, raw clay has been used long before firing it for durability was invented.

  
  

  
  

  Figure 1. Clay construction, Burkina Faso

  
  

  

  
  

  Figure 2. Different clay materials

  
  

  
  

  Clay is a very fine, naturally occurring type of soil created by weathering of different types of rock. Clay can be found practically all over the world, in different places and in different colors. Different types of clay include e.g. kaolin, ball clays, red clays and other natural clays. Theoretically, geologists define clay as a type of mineral soil in which at least 30% of the particles are less than 0.002 mm.

  
  

  
  

  
  

  Figure 2. High circulation of a substance (translation will be included asap)

  
  

  Primary clays are residually deposited clay minerals, such as kaolin and bentonite. Primary clays are often the purest clays. Secondary clays are clay minerals that have migrated to other areas of origin and contain varying amounts of impurities. Secondary clays include, for example, ball clays and natural clays.

  
  

  Most naturally occurring minerals are a combination of silicon (Si) and oxygen (O), but they often contain other common crustal elements such as iron and aluminum. These substances are called silicate minerals. Silicates are the key raw materials for ceramics. By combining them and firing them at high temperatures, different clay bodies and glaze surfaces are obtained.

  
  

  Theoretically, the chemical composition of a clay crystal is expressed by the formula: Al₂O₃ ⋅ 2SiO₂ ⋅ 2H₂O. Clay crystals are flat, hexagonal, microscopically small plates whose shapes and sizes vary according to different clay grades (Jylhä-Vuorio, 2003).

  
  

  
  

  Figure 3. Clay crystal

  
  

  Different clay bodies and plasticity

  
  

  A mixture of clay minerals and other raw materials is called a clay body. Clay bodies can be found directly in nature (red clay, natural stoneware clays), but in practice most clay body mixtures are industrially produced. Typical properties of clay bodies are plastic and non-plastic.

  
  

  Plasticity in physics is a property of matter in which the effect of force on its shape results in irreversible deformations. The plasticity of clay means that the clay body can withstand stretching and machining without tearing. The smaller the clay particles, the greater the plasticity they provide in the clay body.

  
  

  A fine, plastic body is called fat (versus short). Because the fat and fine-particle body holds a lot of water, its drying shrinkage is high. When drying, a body with a large shrinkage rate causes defects in the object, such as cracks. To avoid defects, the clay bodies can be adjusted with non-plastic raw materials such as quartz, feldspar and crushed clay, i.e. chip or chamotte. Non-plastic raw materials reduce shrinkage during drying, i.e. drying shrinkage (Jylhä-Vuorio, 2003).

  
  

  Plastic or non-plastic clay bodies are suitable for various manufacturing techniques. Plastic compounds are suitable for throwing, hand-building and molding. Compression powders and granules of non-plastic clay bodies are used in industrial production. Casting slip, or casting clays, are fluid mixtures, in which a form is usually made using a plaster mold.

  
  

  The plasticity of different clay bodies is regulated by their raw material composition. Raw materials are divided into plastic and non-plastic raw materials. Plastic raw materials include, for example, kaolin, ball clays, red clays and bentonite. Non-plastic raw materials include feldspar, nepheline syenite, quartz, flint, grog and fibers.

  
  

  Ceramics

  
  

  Ceramics are clay fired at high temperatures. After drying, the clay can be converted back to plastic form by mixing it with water countless times, but if the clay is heated to a temperature above about 600 ° C, it becomes a hard substance that is no longer soluble in water and does not return to its plastic form. Because of this hardening, pottery is called an eternal material because it never decays, but at most shatters and crumbles.

  
  

  Ceramic change means that clay never ever returns to a plastic body, its minerals have changed their chemical crystal structure under the influence of heat and clay has changed into a new, durable material, i.e. ceramics.

  
  

  The term ceramic is used for inorganic materials made at high firing temperatures. In everyday language, the word ceramic often refers to the so-called technical ceramics, which are new materials developed in recent decades. Technical ceramics include very strong materials that are used to replace e.g. metals.

  
  The term ceramics is used for objects made from clay-based raw materials that have undergone a ceramic firing process. Ceramics can be divided into two groups according to the degree of processing of the raw materials used: coarse ceramics and fine ceramics. Conventional coarse ceramic products include various bricks and brick elements. Fine ceramics can be considered to include, for example, household and sanitary ceramics.
  
  
  

  Glaze

  
  

  Glaze is a thin layer of glass on the surface of the ceramic body. Glazes are named according to their composition, appearance, firing temperature and firing method. They can be glossy, matte, translucent or opal in visual properties. The glazes may have crystals or may be completely clear. Glazes can be stained with metal oxides and pigments. The raw materials they contain or clay base can affect the properties of the glaze. Firing conditions also affect the appearance of the glaze.

  
  

  The glaze is selected according to the firing temperature of the clay body used. For example, low-fire bodies are glazed with low-fire glazes (900–1180 °C) and high-fire clay bodies are glazed with high-fire glazes (1200–1400 °C).

  
  

  Glaze is used for many different reasons. In utensils, the glazed surface is more hygienic and easier to keep clean than the unglazed surface. In addition, the glaze improves the wear resistance of the object and makes the object waterproof. There may also be purely aesthetic reasons for using glaze. For example, it can improve the appearance of an object and smooth out defects visible in the body. In art ceramics, the visual properties of the glaze can go beyond usability requirements.

  
  

  The properties of the glaze are substantially affected by the raw materials used, the clay body used, the firing method, the firing temperature, the thickness of the glaze layer and the composition of the glaze mixture. By their nature, glazes are not precise chemical compounds, but mixtures whose melting is affected by several simultaneous eutectic reactions. The properties of the glaze are regulated by changing their chemical composition, i.e. the amount of compounds in relation to each other. The basic raw material and glazing agent of the glaze is silica SiO₂ obtained from quartz sand. In addition to quartz, fluxes are added to the glaze to lower the melting temperature, usually in the form of feldspar minerals and frit. In addition to these, many other ceramic oxides act as glaze fluxes.

  
  

  Glazes are divided into two groups according to the firing temperature: low-fire glazes 900–1180 °C and high-fire glazes 1200–1400 °C. The breakdown is indicative. Both groups include glossy, semi-matte, and matte glazes depending on the surface melt.

  
  
  

  Ceramic clay-based coatings

  
  

  A simple surface treatment for ceramics can be done by burnishing. Burnishing takes place when the object is in the raw or greenware stage and the surface is dry. The surface is rubbed, for example, with the bottom of a spoon or a smooth stone. In this way, the porous surface of the clay becomes shiny and dense as the smallest particles pack in a dense layer on the surface of the object. (Salmenhaara, 1983). Polishing with burnishing is only suitable for low temperatures, as at high temperatures the melting reactions of the clay body remove the resulting shiny effect.

  
  

  A slip called Terra Sigillata is closer to an engobe than glaze, although it sometimes resembles a very thin layer of transparent glaze. Terra Sigillata is made by separating the finest part of the clay. (Salmenhaara, 1983). It was used to decorate high-quality pots in ancient Greece. The result was a dense, glossy, water- and dirt-repellent surface with very precise, detailed Illustrations.

  
  

  Engobe is a generic name for clay slip, which often consists essentially of the same raw materials as the clay body of the object itself. An engobe has a wide range of applications and is suitable for both low and high fire. Engobes can, for example, be painted, sprayed or dipped for surface application of an object. It is colored by mixing metal oxides or pigments. (Salmenhaara, 1983). An engobe can be added to the surface of an object when it is leather-hard, completely bone-dry, or bisque fired. The range of possibilities of engobe surface decoration are very wide, and it is possible to layer different colored translucent glazes to create a wider range of colors and surfaces.

  
  

  References

  
  

  Brinck, J. (2019). Keramiikan valmistuksen prosessi sekä valmistus- ja koristelutekniikoita [Unpublished teaching material]. Aalto university.
  Currie, I. (e.p.) Understanding Glazes. http://glazes.org/
  Hortling, A. (e.p.)  Keramiikan värit ja pigmentit. University of Art and Design Helsinki. Retrieved 11/27/2020, http://www.airihortling.fi/
  Hortling, A. (e.p.) Lasite ja lasittaminen. University of Art and Design Helsinki. Retrieved 11/27/2020, http://www.airihortling.fi/
  Jokinen, E. (2019). Keramiikan kemiaa, empiirinen kaava [Unpublished Teaching Material]. Aalto university.
  Jokinen, E. (2019). Lasiteluento [Unpublished teaching material]. Aalto university.
  Jokinen, E. (2019). Saviluento [Unpublished teaching material]. Aalto university.
  Jylhä-Vuorio, H. (2003). Keramiikan Materiaalit. Kuopio: Taitemia.
  Lautenbacher, N. (2016). Keramiikan materiaalit ja poltto [Unpublished teaching material]. Aalto university.
  Pelkonen, T. (2009). Massojen ja lasitteiden valmistus [Unpublished teaching materials]. Aalto university.
  Salmenhaara, K. (1983). Keramiikan Massat, Lasitukset, Työtavat. Keuruu: Otava.

  
  
  

  Reading recommendations

  
  

  Au, D. (n.d.) Glazy database. https://glazy.org
  Cordes, U. (2019). Online Glaze Calculator. https://www.online-glaze-calculator.com/Calculator/fr2.php
  Britt, J. (2018). Ceramics Arts Network. https://ceramicartsnetwork.org/daily/ceramic-glaze-recipes/glaze-chemistry/triaxial-blend-test-pottery-glazes/
  Daly, G. (2020). Ceramics Arts Network. https://ceramicartsnetwork.org/daily/ceramic-glaze-recipes/glaze-chemistry/line-blends-a-surefire-way-to-build-your-understanding-of-ceramic-glaze-materials/

  
  

  Images and illustrations

  
  

  Figure 1. Van der Bent, M. (2013). Cour royale de Tiébélé (jpeg) Retrieved 2.12.2020, https://search.creativecommons.org/photos/d74bcf0e-a1cc-47d2-a058-dec1f1c98a09
  

  Figure 2. Kinnunen, A. (2020). Different Clay Materials. [Photo].
  Figure 3. Kerimov, N. (2020). High circulation of a substance. [Illustration].
  Figure 4. Kerimov, N. (2020). Clay Crystal. [Illustration].
  

  
  

  
  

  
  
  

• From Clay to Ceramics and Ceramic Firing
  

  
  

  Clay objects must be dry before they can be fired. A good way to ensure that an object is dry is to feel it against your skin. If the object feels a little cool, it will probably still be moist even if it looks visually dry. If damp clay objects are fired, the steam coming out of the inside of the object may explode the object or cause cracks during firing. However, when drying earthenware, it must be remembered that the drying is done slowly and evenly enough that the shrinkage during drying does not cause the objects to warp or crack. The thicker the wall of the object is, the slower it must dry.

  
  

  During the firing process, the clay transforms into ceramics. During firing, several different reactions take place, such as sintering, softening, and then eventually clay body melting if the firing temperature is too high. During firing, the free water is first removed from the clay, and then its crystal water, as the firing progresses. The particles of the clay body components melt together and form a new durable material.

  
  

  Changes in ceramics caused by firing

  
  

  Sintering is a key phenomenon in the ceramic process, which can also be called vitrifying. Sintering is a series of reactions in which part of the body melts at the same time as other parts only begin to adhere to each other. In connection with sintering, the total volume of the material decreases while the material becomes denser and stronger.

  
  

  The sintered body is at its softest at peak firing temperatures and then the shape of the object tends to slump. For example, if an object is placed on a bent kiln shelf, it may warp during firing. When the body has softened, its internal stresses tend to be triggered, which causes distortions in the object, for example. This phenomenon is called clay memory. For example, clay memory can be seen ​​at slip-cast seams that have been smoothed unnoticed before firing. However, after firing, the seams may emerge as the stress due to the direction of the settling particles relaxes. Similarly, changing the shape of the mouth of an object from oval to round is easily accomplished while the object is still wet, but during firing, due to the pulling caused by the clay particle memory, the mouth will probably return to a more oval shape.

  
  

  
  

  Figure 1. Clay memory: the finished slip-cast seam reappears during firing

  
  

  If the firing temperature exceeds the sintering temperature of the clay body, the clay body begins to melt. The melting body turns into a soft, semi-solid mass into which bubbles begin to form from the gaseous constituents. At this point, the object loses its shape and eventually melts completely onto the kiln shelf, which can cause great damage to the kiln.

  
  

  As the temperature in the furnace rises, the volume of the pottery increases. This phenomenon is called thermal expansion. As the temperature decreases, the volume of the materials decreases correspondingly. In the making of ceramics, this is particularly important in the coordination of the body and the glaze, since the glaze, when cooled, is subjected to either compressive or tensile stress in relation to the body beneath. The thermal expansion of the glaze should be less than that of the body because the glazes withstand the compressive stress better, in other words, the body should shrink more than the glaze during cooling.

  
  

  The change in size after firing compared to the dry size of an object is called firing shrinkage. The denser the fired clay body, the more it shrinks. The shrinkage of a stoneware clay body is usually about 13%, slightly more with porcelain (14–16%) and considerably less with porous red clay. Changes during firing are taken into account in the design and making phase of the ceramic artefact. The fired product is also lighter than the unfired, because in addition to the removal of free water, organic matter and crystal water evaporate.

  
  

  Figure 2. Post-firing changes, such as firing shrinkage, are seen when the unfired and vitrified fired pitcher are compared. Pitcher by Nathalie Lautenbacher

  
  

  Firing temperatures of different clay bodies:

  Porcelain: 1200–1400 °C

  Stoneware clays: 1150–1300 °C

  Low firing clays (earthenware, earthenware and red clays): 1000–1100 °C

  
  

  Bisque firing and glazing firing

  
  

  Bisque firing refers to the first firing of objects to a temperature of about 800–950 °C. The purpose of this firing is to make the objects durable enough to easily handle when glazing. The bisque fired body is porous and absorbs water from the glaze, whereby the glaze adheres to the surface of the object. In bisque firing, a slow start is important so that any free water left in the pores can evaporate away. Crystal water is also removed at the beginning of firing (400–650 °C). Firing should be slow so that all firing reactions have time to complete. Contaminants remaining in the clay body during bisque firing can cause vitrification defects when gassing during glaze firing.

  
  

  For bisque firing, objects can be stacked together or even gently stacked on top of each other.

  
  

  Figure 5. Bisque firing curve

  
  

  In glaze firing, objects are fired to as high a temperature as the melting of the glaze requires. At the same time, the body is made to sinter in the desired manner into a suitably dense and durable object. The final glazing temperature varies depending on the clay type used and the glaze. A fast or slow heat rise program affects the melting of the glaze and some glazes require deceleration at different stages of firing. For example, in crystal glazes, the crystals grow in a cooling glaze, which is why the glaze firing is held at different cooling temperatures for several hours, depending on how large and what shape crystals are sought. (http://www.airihortling.fi/Lasite_ja_lasittaminen.pdf).

  
  

  Before firing, the glaze is carefully wiped from the bottom of the bisque fired objects so that they do not stick to the kiln shelf. The objects are loaded in the kiln so that they do not touch each other.

  
  

  
  

  Figure 6. Glazing firing curve 1250 °C

  
  

  Different firing methods

   

  Before looking at different methods of firing ceramics, such as gas and electric firing, let’s open up what firing atmospheres mean.

  
  

  Firing Atmospheres

   

  The firing atmosphere refers to the firing climate in the kiln during firing. The firing atmosphere is affected by the amount of oxygen in the furnace space, which in turn affects the appearance of both the clay body and the glaze.

  
  

  Neutral firing means firing in which firing reactions take place to completion. In other words, firing consumes only the amount of oxygen used by the firing reaction in question. During neutral firing, the furnace is free of excess, free oxygen, and carbon monoxide (CO). In an electric kiln, the firing is usually neutral. Neutral fired glazes are typically brighter than reduction fired glazes, especially at lower temperatures.

  
  

  Oxidation firing occurs when more air is introduced into the furnace than would be necessary for firing. Oxidation firing can be achieved by opening the kiln ventilation hatches or by opening the kiln door lid. As a result of oxidation firing, for example, copper oxide, which has already been reduced once, can be oxidized back to its original color.

  
  

  Reduction firing is often done in a gas or wood kiln. The reduction is achieved when not enough oxygen is released into the burner housing for complete firing. This produces carbon monoxide (CO) in the furnace. Carbon monoxide tends to bind with another oxygen atom, and some metal oxides used in ceramics, in turn, can release oxygen atoms during firing. Reduction occurs when oxygen is removed from these compounds. In practice, the most visible change occurs in the coloring of ceramics: for example, brown iron oxide (Fe₂O₃) and changes to blue-green (FeO) during firing. Another easily reducing non-ferrous metal oxide is a greenish copper oxide that turns red during reducing firing. There are glazes designed for reduction firing, e.g. Celadon and Ox blood.

  
  

  Firing Methods

  
  

  Ceramic kilns are divided into two main types: gas and electric. The gas kiln is heated by firing fuel such as oil, gas or wood in the kiln or burners. In these kilns, the flames enter directly into the kiln space and are in direct contact with the objects being fired. Gas and wood kilns are particularly well suited for Reduction firing. The heat required in an electric kiln is generated when an electric current is directed to the electric heaters inside the kiln, called elements. The atmosphere of the electric kiln is neutral when the kiln space is closed. Oxidation firing is achieved when the kiln vents or door are cracked.

  
  

  Raku is a Japanese firing method in which objects are lifted from a kiln at the peak temperature of firing and placed in a container containing combustible material (often sawdust). The smoke penetrates the pores of the hot body, staining it black. At the same time, many glaze colorants can be reduced. After smoking, the objects are rapidly cooled in a water vessel. Raku objects are characterized by cracks in the glass surface that occur during cooling due to thermal shock. Raku should only be fired by an experienced professional, as there are several dangerous steps involved in the firing.
  
  

  Wood firing is the traditional and oldest method of firing ceramics, in which wood is used as fuel for the kiln. Wood firing requires a lot of time as logs are added to the firing chamber throughout the firing process. Firing generally takes 14–30 hours. During firing, the appearance of clay bodies and glazes is greatly affected by the flame and smoke formed in the kiln space, as well as the ash. Traces of flame form on the object and molten ash can glaze the surface of the unglazed object. In a wood kiln, clay bodie and glazes can also be reduced, so glazes from reduction firing such as Celadon and Oxblood work well in wood firing.
  
  

  In salt firing, moistened coarse salt, i.e. sodium chloride, is thrown into the furnace at the sintering temperature of the clay body, whereby the silica contained in the surface of the clay body reacts with sodium to form a glass coating. The glaze layers and thickens as the firing continues. The more times the salt is thrown, the thicker the glaze is formed. The method requires a kiln type in which a flame carries salt inside the furnace during firing. The temperature of the clay body depends on the firing temperature of the salt glaze, which must be at least 1100 °C, at which point the salt begins to evaporate. (http://www.airihortling.fi/Lasite_ja_lasittaminen.pdf).

  
  

  Kiln Programming and Loading
  

  
  

  Instructions for kiln programming and loading you will find in the Studio practices and equipment section.
  

  
  

  
  

  References

  Brinck, J. (2019). Keramiikka: värit ja polttaminen [Unpublished teaching material]. Aalto University.
  Hortling, A. (n.d.) Lasite ja lasittaminen. University of Art and Design Helsinki. Retrieved 28.11.2020, C.
  Jokinen, E. (2019). Lasiteluento [Unpublished teaching material]. Aalto-yliopisto.
  Jylhä-Vuorio, H. (2003). Keramiikan Materiaalit. Kuopio: Taitemia
  Lautenbacher, N. (2016). Keramiikan materiaalit ja poltto [Unpublished teaching material]. Aalto-yliopisto.
  Zakin, R. and Bartolovic, F. (2015). Electric Kiln Ceramics. American Ceramic Society. Retrieved 4.12.2020, https://ceramicartsnetwork.org/daily/firing-techniques/electric-kiln-firing/quartz-inversion-and-other-important-stages-of-firing-pottery/ 
  

  
  

  Images and illustrations

  Figure 1. Kerimov, N. (2020). Clay memory. [Illustration].
  Figure 2. Kinnunen, A. (2020). Post-firing changes. [Photo].
  Figure 3. Kerimov, N. (2020). Bisque firing curve. [Illustration].
  Figure 4. Kerimov, N. (2020). Glazing firing curve 1250 °C. [Illustration].
  

  
  

  
  
  
  
  
  
  
  
  

• Ceramic Techniques
  

  
  

  When designing ceramic objects, it is necessary to consider what technique should be used to realize the object and shape in question. Various best-known techniques include e.g. hand-building, such as coiling and slab building, and techniques suitable for small-scale production, such as throwing, casting and molding, and 3D printing. Techniques can also be combined with each other, and many makers develop techniques of their own that differ from the above-mentioned, most commonly used techniques. Researching techniques can also be a starting point for doing so, and experiments can lead to new, surprising results.

  
  

  Once the technique used in the making has been selected, the clay body best suited to it is considered. For example, it is good to have a chamotte or grog in hand-built clay, which stiffens and reduces the drying shrinkage of the object. The wheel throwing clay must be plastic and sturdy, but it must be kept in mind that too rough a chamotte can break the skin of the hands when throwing.

  
  

  At the design stage, it must be remembered to anticipate firing shrinkage, as clay shrinks during firing depending on the clay quality; the firing shrinkage of porcelain is about 14–16% and that of stoneware about 13%.

  
  

  Drying is an integral part of the making process. There is a risk of cracking if the work dries too quickly or unevenly. Therefore, it is a good idea to cover the work with plastic, newspaper or cloth in the early stages of drying, because when lightly covered, they dry more evenly. The thicker the object, the longer it takes to dry. Depending on the humidity, a large hand-built sculpture may need to be dried for up to several weeks. After bisque firing, the objects can be glazed, after which they are glaze fired according to the quality of clay used. After glazing, the objects can still be decorated with, for example, decals or painted with china paints. The decals and china paint colors must finally be fired onto the object, the temperature of the decorative firing depends on the decoration used.

  
  

  
  

  Figure 1. Ceramic making process

  
  

  The above techniques and, based on them, advanced, personal working methods are discussed in video interviews and demonstrations of artists and researchers working in the field. In addition to various techniques, the videos reveal the working philosophy of the authors more broadly.

  
  

  Hand-building

  
  

  Hand-building is a method of making ceramics in which objects are made using fingers, hands, and simple tools. The most common hand-building techniques are the coiling technique and slab technique. Clay can also be machined without tools, for example with a pinching technique, in which an object is shaped from a clay ball by pinching with the thumb and forefinger. Different hand-building techniques can also be mixed together and combined in the same work.

  
  

  In hand-building, it is good to use plastic and sturdy clay, which contains 0.5–2.0 mm chamotte 25–50%. The chamotte also facilitates large jobs, especially during construction, by solidifying and reducing the drying shrinkage of the object. Paper clay is also well suited for hand building, as the fibers brought in by paper make the clay durable in the unfired stage and can be used to build very thin and bulky walls.

  
  

  
  

  Figure 2. Clay wedging

  
  

  Before hand-building and throwing, the clay must be carefully wedged. Wedging improves the workability of the clay and, for example, long-standing clay becomes softer when wedging. Wedging also removes any air bubbles from the clay, which complicates the work, easily splits the object during the drying phase and forms bubbles on the surface of the object during firing.

  
  

  Coiling technique 

  
  

  The coiling technique is a very versatile hand-building method that is particularly well suited for large-scale sculptures and asymmetrical shapes. Elongated coils are formed from plastic clay by rolling the clay with light movements against the table with the help of palms. The clay coils are placed on top of each other as a wall and joined together. The surfaces to be joined must first be roughened, for example by scraping with a fork, after which a clay slurry or slip made of the same clay, which acts as an adhesive, can be applied to their surface.
  

  
  

  
  Video: Kristina Riska
  (Only in Finnish at the moment, we are working with English translations. Please, be patient.)

  
  

  
  

  Slab-building technique 

  
  

  Like coiling technique, slab technique is a versatile hand-building method that is suitable, for example, for making tiles and sculptures. The slabs can be made by using a rolling pin or a clay slab-roller. They are cut to the desired size and shape and joined together, like with the coiling technique. With slab technique, it is possible to create large and uniform surfaces relatively quickly.

  
  

  Video: Johanna Rytkölä
  (Only in Finnish at the moment, we are working with English translations. Please, be patient.)
  

  
  

  
  

  Video: Kirsi Kivivirta
  (Only in Finnish at the moment, we are working with English translations. Please, be patient.)
  

  
  

  Small series

  
  

  Small-scale production is serial production, but its production volumes are considerably smaller compared to industrial serial production. The advantage of small-scale production is freer formulation and a more versatile applicability of different clay bodies as well as glazes and surface techniques, as production is often handcrafted. In small series production, especially arts and crafts, the product designer often also acts as the manufacturer. The most typical techniques used in small series production are wheel throwing, press-molding, jiggering and casting.

  
  

  Wheel Throwing
  

  
  

  Wheel throwing is a manufacturing method in which clay is shaped with a wheel. Turning creates regular, round shapes. The first wheels rotated at a kicking speed, but today most wheels are electrically operated, with the speed of rotation controlled by a pedal. Once the thrown object has dried to leather-hard, it can be placed back on the wheel and trimmed and finished by turning.

  
  

  Good throwing clay is plastic and sturdy, which can withstand the stresses of spinning. Many natural clays, such as Finnish red clay, are well suited for throwing due to their high plasticity. Chamotte is also suitable for throwing clay, but too coarse chamotte wears and at worst breaks the skin of the hands. Throwing clay must be wedged well before use, as inconsistencies in the clay make it difficult to work the clay on the wheel.

  
  

  Steps for throwing:

  -Centering

  -Interior and base forming

  -Wall pulling (lifting)

  -Forming an object

  -Finish

  
  

  Video: Camilla Groth
  (Only in Finnish at the moment, we are working with English translations. Please, be patient.)
  

  
  

  Pressing

  
  

  Pressing combines different techniques; slab technique and molding technique. Press molds are usually made from plaster. The plastic clay is rolled into a slab, cut to the desired size and placed inside or on top of the mold. The clay is pressed along the mold and the clay left over the mold is cut off.
  

  
  

  
  

  

  
  

  
  

  Figure 3. Image series on press molding
  

  1. Press-mold, clay, and a rolling pin
  2. The clay must be made in a slab first.
  3. A rolling pin or slab-roller can be used.
  4.–6. Pressure is applied downwards as the rolling pin is rolled forward to make an even slab.
  7.–9. Use a template the same size as press-mold to cut the right shape slab.
  10.–13. Place slab on mold and press around plaster slump mold until desired shape is reached.
  14.–15. After the clay has dried to leather-hard, it can safely be removed from the press-mold and finished.
  

  
  

  Jiggering

  
  

  Jiggering is a manual molding method used in small series production as well as product development. In manual molding, the plaster mold is placed in a metal chuck that rotates during forming. The jiggering blade (wood, plastic, steel) is lowered by hand on the clay piece as the plaster mold rotates. By jiggering, both internal and external molding can be done.

  
  

  
  

  
  

  
  

  
  

  Figure 4. Image series of jiggering technique
  

  1.–3. The plaster mold is placed into the metal chuck.
  4.–5. The jiggering blade is fixed at the correct position on the arm. The left edge must meet the middle point exactly.
  6.–7. A small piece of plastic clay is placed in the bottom of the mold.
  8.–11. As the mold is spinning, the arm with the blade is lowered slowly in steps, each time removing a small amount of clay. The final shape is found when the arm is pushed all the way down to be horizontal.
  12.–14. When the form is finished, any excess clay on the top rim of the mold can be cut away. The piece can then be removed from the mold after it has dried and shrunk a bit.
  

  
  Slip-casting

  
  

  Figure 5. Casting with a plaster mold (animation)
  
  

  Casting methods are divided into open casting and solid casting. Molds can be single or multi-piece. Casting techniques are used in both small series production and industrial production.

  
  

  In open casting, the casting mass is poured into a mold where it is allowed to set for a certain period of time. During this time, a solid layer of clay gradually increases in thickness on the inner surface of the mold, as the plaster mold absorbs some of the water contained in the casting slip. The thickness of the clay layer is determined by the length of time of the casting slip in the mold, so that by extending the casting time, the thickness of the layer can be increased. When the desired wall thickness of the object has been reached, i.e. a certain casting time has elapsed, the mold is turned upside down, and the excess slip that is still wet is poured out and the already cast solid object remains inside the mold. The object is left to dry in the mold for some time, during which it solidifies due to the continuous absorbency of the mold. When the drying object shrinks slightly, it can be easily removed from the mold.

  
  In solid casting, both internal and external formation of the object takes place by means of a mold. The mold consists of two halves, inside which the shape of the object to be made is repeated. The molds are filled through the pouring openings in one half so that the space between the molds is filled. The water in the casting slip is absorbed into the mold on two sides and the wall thickness is determined by the mold and not by the casting time used as in open casting.

  
  

  3D printing techniques

  
  

  3D printing is a material-adding technique in which printing adds material, for example layer by layer or by continuous extrusion. The following is an example of one way to approach clay printing, but there are several different variations and ways. 3D printing is an evolving field and more and more new printers and suitable materials are entering the market.

  
  

  Printing a piece of clay can be roughly divided into three different work steps. In the first step, a digital file is made of the format of the piece to be printed. For example, Rhinoceros 3D modeling software or other similar CAD software can be used for this. For example, the finished digital file is saved in STL format, after which the modeled format is sliced into layers ​​by another software. The digital file gives the coordinates to the printer, as it moves and prints the media. The second step in the process is printing itself. For extrusion printing, a suitable soft clay must be made that is sufficiently pasty and of uniform quality. The clay can be prepared from start to finish itself or, for example, using ready-made fine clay, to which water is added by hand processing so that the pulp is suitably soft. Printing clay by the extrusion method often requires constant monitoring and, for example, adjustment of the air pressure. During printing, you can still influence the printing process itself, for example by changing the print speed or adjusting the air pressure. However, these possibilities depend on the type of printer you are using. The third step in the process is the finishing step of the printed part, in which the object is dried, finished and fired to the desired temperature in a manner familiar to ceramics.

  
  

  3D printing involves a wide variety of printing techniques and the extrusion method is just one of them. The clay can also be printed, for example, with a powder printer, which prints the clay powder by layer. Different clay 3D printing methods allow for the application of clay material in dry powder or plastic form. In the stereolithography (SLA) method, the ceramic raw material can be blended with a photopolymer that is photoactive. In the SLA technique, the liquid mixture is added stepwise to the basin, after which the surface of the mixture is cured layer by layer by means of a laser beam.

  
  

  The 3D printer for ceramics can be thought of as a new kind of tool for craftsmen, designers and artists, which enables e.g. the production of otherwise difficult shapes and the use of new types of material. As a digital tool, a 3D printer is very different from traditional tools in that it is programmed and requires not only knowledge of ceramics, but also different areas of expertise. 3D printing can be approached from a very technical point of view, as it enables, for example, the production of structurally demanding shapes. It can also be used as a handcrafted tool, and approached from an exploratory and experimental perspective.

  
  

  Video: Ashish Mohite and Priska Falin
  

  
  

  References

  
  

  Brinck, J. (2019). Keramiikan valmistuksen prosessi sekä valmistus- ja koristelutekniikoita [Unpublished teaching material]. Aalto University.
  Jylhä-Vuorio, H. (2003). Keramiikan Materiaalit. Kuopio: Taitemia
  Lautenbacher, N. (eds.) (2020). Kantava maa. Aalto Arts Books
  Lautenbacher, N. (2019). Manufacturing Techniques In Ceramics, Product Design in Ceramics [Unpublished teaching material]. Aalto University.
  Pelkonen, T. (2009). Muodonantomenetelmät [Unpublished teaching material]. Aalto University.

  
  

  Reading recommendations

  
  

  Keep, J. (2020). A Guide to Clay 3D Printing. Retrieved 1.12.2020, http://www.keep-art.co.uk/journal_1.html
  Chittenden, T. (2018). Printed pots and computerized coils: The place of 3D printing in ceramic practice. Craft Research, 9 (1), 9-40.
  Falin, P., Horsanali, N., Hansen, F. T. & Mäkelä, M. (in press). Practitioners ’Experience in Clay 3D Printing: Metaphorical viewing for gaining embodied understanding. Proceedings of BICCS2021 conference.
  Gürsoy, B. (2018). From Control to Uncertainty in 3D Printing with Clay. In Kepczynska-Walczak, A. Bialkowski, S. (Eds.) Proceedings of the 36th eCAADe Conference: Computing for a Better Tomorrow (pp. 21-30).
  Hansen, F. T., & Falin, P. (2016). 3D Printing as a Ceramic Craft Tool in Its Own Right. In M. Mäkelä, B. Schmidt, P. Falin and M. Juolahti (Eds.), Ceramics and its Dimensions: Shaping the Future (pp. 114–128). Helsinki: Aalto University.
  Hansen, F. T., & Tamke, M. (2019). A Visual Programming Interface as the Common Platform for Sharing Embodied Knowledge. In N. Nimkulrat, K. Kuusk, J. V. Noronha, C. Groth & O. Tomico (Eds.) Proceedings of EKSIG2019: Knowing Together: Experiential knowledge and Collaboration (pp. 56-70).

  
  

  Images and illustrations
  

  
  Figure 1. Kerimov, N. (2020). Ceramic making process. [Illustration].
  Figure 2. Kinnunen, A. (2020). Clay wedging. [Photo].
  Figure 3. Kerimov, N. (2020). Image series on press molding. [Illustration].
  Figure 4. Kerimov, N. (2020). Image series of jiggering technique. [Illustration].
  Figure 5. Kerimov, N. (2020). Casting with a plaster mold. [Animation].

  
  

  Videos

  
  

  Latva-Somppi, A., Visuri, K., Aalto ARTS & Hauru I-M., Aalto Studios & Guseva, Y., Aalto Online learning (2020)
  

  
  

• Studio Practices and Equipment
  

  
  

  Kilns and Firing

  
  

  When clay is fired with a well paired glaze to maturity temperature, they become durable ceramics. Variables which affect the appearance of ceramics and the overall studio practice of a ceramicist include: clay body, glaze, type of kiln, type of fuel, kiln loading style, and kiln program. Typical kilns for firing ceramics include an electric kiln, a gas kiln, a wood kiln and a Raku kiln. The choice of a kiln type, and the firing method have a significant effect on the final result.

   

  Electric Kiln Firing
  
  

  There are several different types of kilns and ways of firing, but all kilns have some basic elements in common: a heat source, a highly insulated refractory structure, and a way of controlling air intake. The only exceptions include traditional ways of firing at low temperatures in the ground with found materials from the environment, such as in pit firing. The kiln is loaded by creating a structure of kiln furniture known as shelves and posts. The following are the most common types of kiln firings today.

   

  Electric kilns are the most common type of kiln used today in Finland. Electric kilns are manufactured in different sizes, are very reliable, considerably more sustainable, and require very little knowledge of firing science. These factors make them very popular with all ceramicists from hobbyists to scientists and to professional potters. With what they lack is the realm of variety and surprises that atmospheric firing brings, such as gas reduction, wood firing, or raku. Electric kilns are quite straightforward and easy to use, requiring far less time, manual labor, and maintenance.

   

  Electric ceramic kilns are very simple - they are metal boxes, either square or round and front-loading or top-loading, lined with soft, porous, highly insulating bricks. Electric kilns are powered by electricity which passes through metal coils called elements along the interior walls. These elements are the most frequent piece of an electric kiln requiring maintenance and need to be changed every so often.

   

  The second most common maintenance involves the kiln shelves. The shelves should be covered with kiln wash to be protected from glaze drips. After several firings, the kiln wash starts to flake and chip. This old layer of kiln wash should be scraped and reapplied or patched.

  
  

  Kiln Programming and Loading

  
  

  Electric kilns are either fired manually or with an electronic control pad. Modern electric kilns with electric control pads can control each stage of a kiln program, including cooling, accurately.

   

  The firing program is divided into stages in which the rate of increase of the kiln temperature is adjusted in each stage, so that the objects stacked in the kiln can withstand the temperature rise without breaking. The principle is that the temperature is raised more slowly at the beginning of the firing and the heating rate can be increased gradually, as the temperature in the kiln rises high enough (and has passed both cristobalite and quartz inversion). A typical ceramic firing involves 2–3 steps and a final soaking. The soaking means that the final temperature is reached and maintained in the end for a set amount of time. This allows the temperature in the kiln to stabilize, the objects in the kiln have time to all reach the desired temperature and the chemical reactions during firing have time to take place. Kiln manufacturers also recommended that it's better to slow down the firing a bit before reaching the final temperature so that the firing results will be more even, and the heating elements last a much longer time, as seen in the high fire glaze program below.

   

  Some very basic examples of ceramic firing programs.

  Bisque firing:
  Stage 1: 50 °C/h until 250 °C
  Stage 2: 100 °C/h until 600 °C,
  Stage 3: 200 °C/h until 900 °C.

   

  Low glaze firing:
  Stage 1: 100 °C/h until 250 °C,
  Stage 2: 150 °C/h until 600 °C,
  Stage 3: 200 °C/h until 1020 °C.
  Soaking:  10–20 min.
  
  

  High glaze firing:
  Stage 1: 100 °C/h until 250 °C,
  Stage 2: 150 °C/h until 600, °C,
  Stage 3: FULL until 1100 °C,
  Stage 4: 150°C/h until 1200–1250 °C.
  Soaking: 10–20 min.

  
  

  
  

  
  

  Figure 1. Kiln control pad by Stafford Instruments for Kerako Kilns. Most common at Aalto University. The image shows the basic button functions.

  
  

  Kiln loading structure and safety

   
  

   

  
  

  Figure 2: Electric kiln loading process. 

  
  1. Kiln type: Kerako electric kiln top-loading model.
  2. The kiln can be loaded when it is room temperature, or cool enough to load safely.
  3. The heating elements line in rows inside the kiln, and there should be no debris or shards on them or other damage.
  4. Three very short posts are placed on the very base of the kiln before any shelves.
  5. The first shelf is set on top of them, and then in the following layers, the posts are placed exactly “in the same spot” as in the layer below. The posts should be placed before any ceramic pieces.
  6. Pieces of similar height should be placed on each level, maximizing the efficient kiln loading.
  7–9. The structure of three posts is repeated with each new shelf layer until the kiln is full.
  10. Before closing the lid, make sure none of the pieces are too high or they will be crushed.
  11. Close lid, check program and start kiln. Make sure there are no flammable materials in the kiln.

   

  When loading a kiln, first check that there is no visible damage to the kiln, such as ceramic pieces or glaze from previous firings in the kiln heating elements (metal coils). If there are a lot of loose pieces in the grooves supporting the elements or on the bottom of the kiln, you should remove the pieces or vacuum the kiln before use. The kiln should be cleaned each time after use to prevent random debris from falling on glaze pieces and to keep the kiln firing accurately.

   

  Before loading the kiln, make sure that the kiln equipment or furniture you need (shelves and posts) are intact and free of glaze residues or visible damage. The top surface of the kiln shelves and the ends of the posts are treated with a kiln-wash, which protects and prevents glaze from sticking to the kiln shelf and facilitates the cleaning of the kiln shelves. Kiln-wash usually consists of half Kaolin and half Alumina Oxide, basically a paintable refractory coating, mixed with water to the consistency of a glaze. The kiln-washed shelves should always be dry before using them in the kiln. One should be careful of flaking kiln wash, as it can come off in the kiln and fuse to a glazed piece, leaving an unattractive blob. The kiln equipment and furniture are made of a highly refractory material, but is very fragile, so handle them with care.

   

  Never wipe the kiln shelves with bare hands, as it is common for broken pieces to become sharp and glass-like on the surface. It is best to grind off any glaze drips or stuck pieces with a grindstone. Protective gloves, goggles and respirator should be worn when grinding kiln shelves to protect eyes and skin from ceramic shards and avoiding breathing dust.

   

  The goal is always to fire the kiln as full and efficiently as possible. When loaded to full capacity, the kiln firing uses less energy, and the temperature is more even throughout the kiln.

   

  The kiln is loaded with a repeated structure of layers to optimize space and firing accuracy. The stacking pattern is started by placing three support posts on the bottom of the kiln that will line up with the edge of the kiln shelf placed on top and create a stable base. On the next layer, the three support posts are placed at the same points on the shelf. The same pattern of posts between shelves continues each layer to create a strong and consistent weight-bearing structure throughout the kiln stacks.

  Objects in the kiln must not touch any part of the kiln, including the elements, posts or kiln walls. For a bisque firing, objects may be carefully nested or stacked. But objects in a glaze firing should never touch or they will fuze together. After loading the kiln, make sure that the kiln lid or door can be closed without touching the objects.

  
  

  
  

  Figure 3. Fully packed gas kiln before firing with cone packs at the top left and bottom right.

  
  

  Important stages of firing and temperatures

  
  

  Below is a brief outline of important firing temperatures and the chemical changes that are happening to ceramics during the process of heating and cooling. These steps and benchmarks should be kept in mind when creating kiln programs to fire to the correct temperature, to not fire at too fast a rate through major chemical changes, and to cool a kiln slow enough so as not to cause thermal shock and cracking. For additional information please refer to From Clay to Ceramic and Ceramic Firing, section of the Ceramic Handbook.

   

  Basic firing ranges.
  Remember always to check the info on the clay-bag for the correct temperature for your specific clay body.

  Low fire                              Earthenware, 950 –1100 °C, cones 015–1, cone 04 average

  Mid-range                          Stoneware, 1162–1240 °C, cones 2–7, cone 6 average

  High-fire                             High fire stoneware, porcelain, 1263–1326 °C, cones 10 –13

   

  Temperature                     Stage of Firing

  100 °C                                 Water boils causing wet green-ware to explode (if temperature rises too suddenly)

  220 °C                                 During cooling if cristobalite crystals are present in clay they rapidly shrink (3%) potentially cracking ware.

  350–500 °C                        Permanent dehydration of clay occurs. Clay is Chemically changed.

  573 °C                                Quartz inversion happens causing quartz in clay and glazes to expand when heating and contract during cooling.

  600–900 °C                        Organic and inorganic matter is burned off out of clay.

  1100 °C                               Mullite crystals begin forming in porcelain clays.

   

  (Zakin & Bartolovic, 2015)

  
  

  Other Equipment and Tools

  
  Clay preparation and production

  
  

  
  
  

  Figure 7. Pug mill.

  
  

  Pug mill

  
  

  A machine used for mixing and recycling clay. In one chamber with a rotating mixing head the material is added which is then compressed and extruded out of the end into processed clay logs. It is a very efficient machine for recycling and reusing clay waste of various stages of dryness or wetness.

  
  

  Extruder

  
  

  A tool that passes clay through a tube to form coils, often uses different shaped dies to create different profiles of the extrusion. It consists of a metal tube attached to the wall, in which the clay is put. The desired profile of extrusion should match the die in the bottom of the metal tube. A metal arm is attached to a metal circle which fits into the tube and using leverage, pushes the clay though the die. The resulting extrusion can be either solid or hollow and creates a very strong and compressed form.

  
  

  Slab roller

  
  

  Table with a horizontal cylinder with adjustable height attached to a large wheel, which when cranked, moves the cylinder across the table and clay evenly. The slab roller presses and squeezes clay between two sheets of canvas creating an equally flat piece of clay. Often, different pieces of canvas are used for different colors of clay. It is the more efficient and accurate version of a rolling pin and resembles the design of a basic printing press.

   

  Pottery wheel

  
  

  A pottery wheel is a spinning horizontal round piece of metal (or other material) attached to an axis that is controlled and spun by either electricity or manual power. Electric wheels can often spin clockwise or counter-clockwise and the speed is controlled by a pedal. Most wheels have a splash pan, which collects excess water and clay from the wheel-throwing. There are also kick-wheels, which have another larger rotating wheel attached to the main axis instead of a motor that is literally kicked by the thrower to gain momentum and spin. A treadle wheel is a design one step up from a kick wheel that uses a sort of swinging pedal which acts as a crank to maintain spinning speed of the wheel. Especially in Asia, traditional pottery wheels can be found that are spun instead with a stick and are often very low to the ground, allowing the potter to sit on the floor.

  
  
  

  Slip-mixer

  
  

  A slip-mixer is a tank that includes a drill used for mixing and dispensing casting slip. The level of complexity varies, some include: a hose with nozzle and pump to dispense slip and a timer for mixing and agitating. These more complex slip-mixers are most common in studios or factories with high production.

   

  Jigger

  
  

  A jigger is a wheel used for serial production of forms using plastic clay. A concave or a convex plaster mold is held in place and spun on the wheel with a piece of clay inside. Then a retractable arm is lowered with the corresponding interior or exterior shape cut into a profile tool. The profile both compresses, trims, and shapes the plastic clay. When the arm and profile tool are pressed down all the way, the desired form should be made. Jollying is the term used when the arm forms the concave interior shape, and jiggering when the convex exterior shape is formed. Using a jigger is still used as a means of producing circular functional ceramics in high volumes and has the advantage of using a wider variety of clay bodies versus slip-casting.

  
  

  Glaze preparation and glazing equipment

  
  

  
  

  Figure 8. Spray booth.

  
  

  Spray booth

  
  

  A spray booth uses a spray-gun for glaze application. Glaze and compressed air are fed from the tank to the nozzle of the gun, after which a layer of glaze is sprayed on the surface of the object. It is important to spray in a glass cabinet to prevent glaze dust from spreading into the room air. There is also a manual low-tech version which uses a small metal container and the user’s own breath blowing through a tube to spray glaze on a small-scale production level.

  
  

  Ball mill

  
  

  Ball mills are used for grinding minerals, oxides, glazes, colors, or for making terra sigillata. The machine usually consists of water-tight ceramic jars with small ceramic balls inside, which when continuously rolled, mill or grind the material into smaller particles, leaving very fine materials in the end.

   

  Plaster modeling

  
  

  Plaster wheel

  
  

  A plaster wheel resembles a pottery wheel but is usually higher, used standing or sitting, also depending on whether it is a purely electric or a kick-wheel. It is used for making plaster models or prototypes and circular molds. Plaster is cast vertically on a wheel head and left to set to semi-soft or fully set to be formed, carved, and worked. If the plaster is turned when it is still semi-soft, often a profile tool is used to sledge or smear the plaster into shape in the beginning and then refined as it hardens. The plaster can also be tooled free-form with sharp, long handled carving tools, usually aided by a horizontal bar between the user and the wheel for resting the tool or arm for added control. Different plaster traditions vary from different places, such as in the U.S., Europe, and Asia. The system holding the plaster piece on the wheel varies, such as casting a thickness of plaster on the wheel head and using a key system similar to mold keys to avoid having the model come loose spinning. Or some wheels have a separate metal piece that can be screwed in and changed based on the height of the model to act as a sturdy and stabilizing core.

  
  

  Plaster lathe

  
  

  A plaster lathe works just like a wood lathe, where a solid cylinder of plaster is clamped horizontally and spun to be carved and tooled. The plaster must be hard, but fine accuracy can be achieved and objects that are taller are often better executed on a plaster lathe than a plaster wheel.

   

  Safety and sustainability

   

  There are both obvious and unseen, immediate, and long-term aspects that are dangerous within the ceramics working area. These include situations involving kilns, clay and glazes, plaster, and studio equipment.

   

  One must be aware of these risks before working in the studio in consideration with their own well-being and the safety of others. Above all, the health of an individual relies on the facilities remaining maintained, organized, clean, and used by considerate and informed users.

  
  

  Health and Safety

  
  

  Kilns

  
  

  Kilns are large industrial ovens that get very hot. Before touching a kiln, you should look at the temperature to know whether it is appropriate or safe to open it or touch it. When a kiln is cooling it can be propped open at 300 °C and opened at 200 °C. The objects can be taken out of the kiln only after it is safe. One should always be especially mindful of the kiln user and consult their wishes for cooling before opening a kiln.

  
  

  Heat and PPE (personal protection equipment)

  
  

  The kilns are insulated with soft bricks, but as the kilns are fired between 800–1300 °C, the metal outside surface of the kiln still becomes very hot. Before a kiln is started, always make sure nothing is left on top or nearby that could catch fire, such as a wooden board used to carry work. When opening a hot kiln, unloading work and shelves, one should always use special heat refractory gloves. When glaze melts to the kiln shelf or a piece is broken, one should be very careful to also use gloves for cleaning, as the glaze and ceramic pieces become sharp like glass. When cleaning the kiln shelves, also protective eyewear and respirator is needed.

   

  Kilns should always be cleaned after use. If there is an error or some equipment broken, it should be reported to the kiln master, addressed, and restored in a timely manner. All experimental firings, for instance containing organic material, need to be discussed with the ceramic studio master or carefully planned, as they can cause dangerous smoke, fumes, or harm to the equipment.

   

  Hazardous kiln gases

  
  

  Firing with salt creates hydrochloric acid, which is poisonous. It should not be used indoors, and if firing a salt kiln outside, the area should be vacated after inserting the salt into the kiln. In recent decades, soda (sodium bicarbonate or commonly known as baking soda) has been used as an alternative, producing its own unique effects.

   

  All kiln firings create harmful fumes containing carbon monoxide, sulphur dioxide and fluorine compounds. Kilns should always be in a separate room from the studio and well ventilated.

  (Health & Safety, n.d.)

   

  Interview with Keracomp

   

  The following is an interview with Kimmo Lattu of the company Keracomp about kiln guidelines, safety, and regulations. Keracomp was founded in 1974 in Porvoo, Finland first to manufacture kilns for schools and smaller ceramic companies and now has widened its scope to develop also different kinds of heating equipment and other kinds of ceramics equipment (Keracomp OY, 2020). Their products and relevant equipment information can be found on their website: https://keracomp.fi/

   

  1. What are hazardous kiln situations to be avoided for personal safety?

  Actual hazards can be created in two ways.

  Firstly, open the hot kiln without suitable protection. For this reason, the instructions for kilns recommend a certain temperature limit, which must be met before opening the kiln (of course this also affects the durability of the kiln structures and objects).

  Secondly, interference with electrical installations. As with all electrical equipment, changes can lead to a situation where the danger to life is imminent but also to a situation where the danger does not materialize until years later.

  2. What are the ways to avoid equipment deterioration?

  Careful work and immediate cleaning are key aspects. That is, the user needs to know what materials are put in the kiln, and how they behave at a certain temperature. This avoids breakdowns of objects, glaze spills, which always strain the kiln and kiln equipment as well.

  If and when something breaks down in the oven, it is important to clean all the splinters and splashes out of the kiln, for example by vacuuming. If something has melted on the inside of the kiln, you should remove it even if it breaks the brick surface. For example, a glaze drip melts a little deeper into a brick in every firing. And a red clay chip between the elements will melt across the element in the next high firing.

  Another issue is the control of water vapor released from objects. It is good to get water vapor directly out of the kiln, since as it passes through the structure it condenses on cooler metal surfaces and promotes their corrosion.

  3. With electric kilns, how often are the elements changed and how do you know?

  According to the need. Visually, the best means of assessment is a change in the shape of the element coil. The element in the groove starts to fall, the loops rest against each other and the element starts to hang and/or accumulate in a tight bundle. Following the process, a strong symptom of the need to replace resistors is a clear prolongation of glazing firing; as it ages, the power of the resistors decreases, increasing the duration of combustion. For industrial use, controllers are available that monitor the power of the resistor groups and warn the user when a certain limit value is exceeded.

  4. Are there clear laws in Finland for where a kiln can be installed?

  No. The matter is mainly regulated by three factors.

  The kiln manufacturer/importer must state the environment in which the oven may be installed. This must be taken into account, for example safety distances for fire safety. This is included in the requirements for the CE marking of the appliances and can be found in the kiln's operating instructions and from the manufacturer/importer.

  From a construction engineering point of view, the information provided by the kiln manufacturer is indicative and the construction industry has its own practices and regulations for resolving issues related to materials and building services.

  The regulation of ventilation in buildings and workspaces again sets its own requirements, and these methods are typically chosen according to the use of the space in proportion to the number of people using the space. In public spaces, ceramic kilns are often required to be ventilated separately.

  5. Are there specific regulations for ventilation for different kilns?

  There are not. From the point of view of the ventilation of the room, the purity/impurity of the air released into the room and the heat load released from the furnace are essential. As I mentioned above, ceramic kilns often have their own discharge channel, but the dimensioning issue is always dependent on the whole.

  6. How does kiln loading affect a firing?

  Vitally. Even stacking is a prerequisite for even temperature distribution. The mass of the objects to be loaded into the oven should be distributed as evenly as possible inside the kiln. In practice, even if the kiln is not filled but the firing is forced to start, the kiln should be filled with extra kiln furniture so that the objects are evenly distributed around the kiln. The goal in this case is therefore not that the kiln is loaded as tightly as possible, but the stacking as evenly as possible, as the extra space only takes up energy unnecessarily.

  7. Is it more sustainable to work in low-fire materials?

  Yes. Low combustion temperatures have several advantages. The energy savings are obvious, but at least as important is the extension of the life span of the kiln structure and elements. This is of great importance when you consider that the production of kiln materials has already required quite a lot of energy. It can be compared to a car, for example, if the car is always driven as hard as it can be, emissions and maintenance costs are high and service life is short.

  8. Is it more sustainable to use electricity or gas?

  There are probably no big differences in energy consumption in studio use. More important for the environment is the source of energy produced. Electricity generated by wind power is certainly more sustainable than natural gas, and natural gas is more sustainable than electricity produced by coal power.

  9. Is it possible to install a personal gas kiln in Helsinki?

  I think it is. A property owner, fire inspector and building inspector will probably be needed. Here, too, the whole is decisive, that is, what and where.

   

  Clay and glazes - dust, food-safety, and hazardous materials

  
  

  
  

  Figure 9. Shovel of raw material dust.

  
  

  Avoiding dust and other healthy studio practices

  
  

  Clay and glazes are made up essentially of silica-based raw materials and pose the largest health risk when airborne. The particles are very tiny, not visible to the human eye, and therefore are an unseen risk over a long time and repeated exposure to the lungs. The worst side effects of long-term silica dust inhalation are pulmonary fibrosis (silicosis) and lung cancer.

   

  Good and healthy studio practice includes tidiness and cleanliness. Floors and surfaces should always be cleaned with a damp tool to suppress as much dust as possible. The largest most common overlooked hazards are dirty floors. As feet walk over dry clay and glaze debris, it is broken down, agitated, and becomes dust in the air repeatedly.

  
  Ceramic materials should never be ingested. Wearing a mask or respirator for fine particulates is most important when mixing powdered raw materials, spraying glaze, or grinding kiln shelves, as in these cases the materials can be even visibly airborne as dust.

   

  Also, to avoid dust, bisque ware should never be sanded dry. The bisque ceramic piece should be fully wet, and saturated with water and sanded with wet-dry sandpaper.

   

  Certain low-fire surface applications should be used with caution, a vapor mask, and good ventilation, including china paint and luster.

   

  Food safety

   

  If you make ceramic items for cooking or eating, check the food safety of the glaze with the manufacturer or seller. The food safety of a functional ceramic dish depends on the glaze surface, clay body and glaze maturity, and application. There are laboratories which will test the safety of a glaze surface (such as EVIRA), but most common glaze defects are harmful over long-term use and are visible quickly. The interior surface that is used with food or drink, should be glossy or semi-matte and unbroken. Matte glazes are often composed of tiny bubbles imperceivable to the naked eye. Cracked glazes should also not be used. These sort of breaks in the surface no longer contain glaze chemicals in a sealed glassy layer, but allow chemicals to leach out over time, especially with acidic liquids like coffee or orange juice.

   

  If a cup is crazed, you will often see signs of liquid passing into the ceramic body from the inside through the exterior or foot and eventually staining. A simple at-home test can be done with a 10% citric acid solution for one week or using even a slice of lemon. If the acid is leaching through the glaze, there will be a change in the color quality of the glaze over even one day. This means the glaze is broken, materials from the glaze can leach into food and drink, food and drink can be trapped in the glaze layer creating mold over time, and the piece is therefore unsuitable for use with food.

  
  

  
  

  

  Figure 10. Different glaze surface qualities.

  
  

  Most metal oxides are hazardous to ingestion. This means they should be processed with extra caution while mixing and disposing of them. Hazardous waste that goes into the sink can eventually enter groundwater and cause larger pollution. Such as at Aalto University, any glaze material that is hazardous, or completely unknown should be treated as hazardous, and put into the hazardous waste drum in the glazing area. This metal drum, when filled, is disposed of by a waste management company. Below in the Sustainability section, there are different methods explained to recycle personal hazardous waste that are more cost effective and ecologically minded.  As discussed in the first Ceramic materials section under Metal Oxides, the most common hazardous material compounds to be used with caution are: cobalt, copper, chrome, nickel, barium, and manganese (firing fumes).

  Materials and recipes using lead, uranium, and cadmium are no longer used due to their toxicity.
  
  Please note! Any materials brought from outside into the university setting must be approved by the studio master.

  
  

  M/SDS safety sheets

  
  

  MSDS or SDS or material safety data sheets are important documents provided upon request by a material supplier or manufacturer for ceramic raw materials, clay, glaze, etc., to provide information on risk, contents, and safety. The exact requirements vary from each country, but the information below is most common for ceramic materials.

  MSDS include following information of a product or a raw-material:

  -        identification and use

  -        hazardous ingredients

  -        reactivity data

  -        toxicology properties

  -        preventative measures

  -        first aid measures

  -        date and who has prepared the MSDS

  (Spectrum Glazes, n.d.)

  For samples, one can visit https://www.spectrumglazes.com/msds.html to view hundreds of MSDS for Spectrum products. This is an essential document for transparency of materials that are otherwise completely mysterious. The Finnish Safety and Chemicals Agency discusses these safety data sheets as well on their website https://tukes.fi/en/chemicals/reach/safety-data-sheet.

  
  

  Plaster

  
  

  Plaster should be treated the same as any other dry ceramic material, as prolonged inhalation can cause asthma (see section above). When measuring dry plaster, a mask should always be used in addition to ventilation. All plaster pieces should be cleaned from the working area and placed into the trash. Plaster on the ground will be stepped on and suspended in the air as dust when broken down. Plaster should never go down the sink, as it clogs the drains over time. Surplus plaster is always emptied in

   

  If making a plaster mold of a body part, it requires extra caution, and a professional should be consulted. Liquid plaster should not be used immediately against the skin, as the plaster becomes hot during the chemical reaction of its setting and hardening and can burn the skin. Also, a body part, such as a hand, can become stuck in a solid, stone-like piece of plaster which can only be broken open by force. Plaster should never go down the sink, as it clogs the drains over time. Excess plaster is emptied from the bucket into a dedicated container, never rinsed out down the drain.

   

  Studio Equipment

  
  

  Any machine that spins should be used with hair tied back and without clothes with strings or other parts that can be caught. Machines, such as mixers and blenders, should always be turned off or unplugged when cleaning or not in use.

   

  Some studio equipment is heavy and in multiple pieces, such as banding wheels and plaster molds. Always band/strap molds together before moving and hold banding wheels by the base, as the bottom can fall out of the top. This will avoid dropping heavy things on your toes.

  
  

  
  

  Figure 11. Aalto University ceramic workshop layout. The equipment has been organized in the space to create different areas for different tasks, such as plaster work, firing, clay work, glazing and slip-casting.

  
  

  Sustainability

   

  Individual potters have traditionally kept frugal and sustainable practices concerning material waste, water use, and fuel use. For sustainable purposes, it is functional practice to use low and mid temperature clay as opposed to using the most refined high-fire clay, e.g. porcelain. This reduces the energy needed for firing and opens up more local alternatives for materials, since there is no major source of the fine materials used for porcelain locally.

   

  It is common practice that rinsing and collection systems are used in various technological forms in ceramic studios, since the clay will clog drains, water costs money, and the collected material can be used again. One of the great things about clay is that it can be reused infinitely before it is fired and undergoes chemical change.

   

  Recycling Clay

  
  

  Ceramicists are in the habit of recycling all their clay scraps to be rehydrated into newly workable clay.

  Basic way to recycle plastic clay:

   

  1.      Break clay into small pieces in a bucket

  2.      Let it become bone dry

  3.      Fill the bucket with water to cover clay pieces

  4.      Wait for the clay to become saturated, broken down, and soft

  5.      Pour off any extra water

  6.      Hand mix or blend with a drill and mixing head

  7.      Spread clay slurry onto plaster slabs for drying

  8.      Flip the clay when the bottom has dried a bit and become plastic

  9.      Wedge clay once it is no longer wet or slippery

  10.   If clay is still too wet, it can be made into small arches, left to dry, and wedged again

   

  For very large batches of recycling, a pug mill is suggested, which can mix, recycle, and de-air clay of different wetness at the same time.

   

  A similar process can be used for casting-slip. Small bone-dry pieces can be added to dry raw materials when mixing fresh casting slip. A rule of thumb is to not use more than ½ of recycled casting slip material in a batch, as too much recycled casting slip can cause more interior casting surface defects. For instance: 25kg new raw materials + 25 kg recycled casting slip + 20-25 liters water + 80 g Dispex.

   

  Recycling Glaze

  
  

  Glaze waste, containing the most hazardous minerals for ground water, is often mixed into a new random glaze, or into the clay of a different product. This way, the color from this waste can be used and contained in an artifact rather than becoming contaminated waste. Often in the studios, there is too much waste to process and it is collected over time in a container for hazardous waste. Below are some alternate examples of projects and research into processing hazardous ceramic waste and moving towards a more sustainable ceramics culture.

  
  

  References

  
  

  Bloomfield, L. (2017). Science for Potters [Excerpt]. American Ceramic Society.  https://ceramicartsnetwork.org/daily/firing-techniques/electric-kiln-firing/firing-clay-lowdown-ceramic-firing-process/

  Finnish Safety and Chemicals Agency, Tukes. (n.d.). Safety Data Sheet. Retrieved 3.12.2020 from https://tukes.fi/en/chemicals/reach/safety-data-sheet

  Frenzel, H. (2020, October 26). How to fire a gas kiln efficiently: perfect combustion in a gas kiln. Ceramic Arts Network Daily. Retrieved 30.11.2020 from https://ceramicartsnetwork.org/daily/clay-tools/ceramic-kilns/fire-gas-kiln-efficiently/

  Galloway, J. (n.d.). Chemicals: Use and Disposal. Retrieved 30.11.2020 from

  http://ceramicsfieldguide.org/chapter-5/chemicals-use-and-disposal/?fbclid=IwAR1q3vBS1AHtLFJj-doRlEM6ojsQtXkDCkizEReb2faNlUcNWdWR90S4KuQ

  Gebhart, T. (2020, November 27).  All about pyrometric cones. Ceramic Arts Network Daily. Retrieved November 30, 2020, from https://ceramicartsnetwork.org/daily/ceramic-supplies/ceramic-raw-materials/all-about-pyrometric-cones/

  Hansen, T. (n.d.) Dunting. Retrieved 30.11.2020 from https://digitalfire.com/glossary/dunting

  Hansen, T. (n.d.) Raku. Retrieved 30.11.2020 from https://digitalfire.com/glossary/75

  Hansen, T. (n.d.) Reduction Firing. Retrieved 30.11.2020 from https://digitalfire.com/glossary/reduction+firing

  Health & Safety. (n.d.) Botz Glasuren. Retrieved 3.12.2020 from https://www.botz-glasuren.de/en/gesundheit-sicherheit-sdb

  Keracomp OY. (2020). Keracomp OY. Retrieved 18.12.2020 from https://keracomp.fi/keracomp-oy/

  KeraSil Oy. (n.d.) KeraSil. Retrieved 18.12.2020 from https://www.kerasil.fi/

  Levin, S. (2017). Wadding for Wood Firing. Retrieved 12.12.2020 from https://ceramicartsnetwork.org/daily/firing-techniques/wood-kiln-firing/wadding-for-wood-firing/

  Spectrum Glazes. (2020). Material Data Safety Sheets. Retrieved 3.12.2020 from https://www.spectrumglazes.com/msds.html

  Murphy, E. (2006). What is Soda Firing? http://potteryblog.com/tag/hydrochloric-acid/.

  Types of firing: oxidation, reduction, salt, wood, raku. (n.d.) Retrieved 30.11.2020 from      https://bigceramicstore.com/pages/info-ceramics-types-of-firing#:~:text=Reduction%20firing%20is%20typically%20done,the%20glazes%20during%20glaze%20maturation.&text=The%20atmosphere%20allows%20pieces%20to%20get%20a%20glazed%20like%20finish%20without%20glazes 

  Pelkonen, T. and McPartlan, M. (2020) Ceramics Workshop. [Unpublished teaching material] Aalto   University.

  Schimik, K. (2018). Sustainability in the Ceramics Studio. Retrieved 30.11.2020 from

  https://ceramicartsnetwork.org/daily/ceramic-supplies/ceramic-raw-materials/sustainability-ceramic-studio/

  Turvallisuus- ja kemikaalivirasto, Tukes. (e.p.).  Käyttöturvallisuustiedote. Haettu 3.12.2020 https://tukes.fi/kemikaalit/reach/kayttoturvallisuustiedote#237668c2.

  Zakin, R. and Bartolovic, F. (2015). Electric Kiln Ceramics [Excerpt]. American Ceramic Society.

  https://ceramicartsnetwork.org/daily/firing-techniques/electric-kiln-firing/introduction-electric-pottery-kilns/

  Zakin, R. and Bartolovic, F. (2015). Electric Kiln Ceramics [Excerpt]. American Ceramic Society. https://ceramicartsnetwork.org/daily/firing-techniques/electric-kiln-firing/quartz-inversion-and-other-important-stages-of-firing-pottery/

   

  Images and illustrations

  
  

  Figure 1. Wikimedia Commons. (2005). Anagama Kiln. [Diagram]. https://commons.wikimedia.org/wiki/File:Anagama_kiln.svg .

  Figure 2. Halko, S. (2014). Woodfired teapot. [Photo].

  Figure 3. Franke, D.I. (2014). Raku. [Photo]. https://commons.wikimedia.org/wiki/File:Raku_15.06.2014_14-28-12.jpg.

  Figure 4. McPartlan, M. (2020). Kiln Control Pad. [Diagram]. [Unpublished teaching material] Aalto    

                University.

  Figure 5. Kerimov, N. (2020). Kiln Loading. [Illustration].

  Figure 6. Haynes, C. (2007). Filled Kiln. [Photo]. https://commons.wikimedia.org/wiki/File:Filled-kiln.jpg.

  Figure 7. Palmer, A.T. (1941). This is the exit end of a pug mill which prepares the plastic clays used in forming various articles of chinaware. [Photo]. United States Library of Congress. https://picryl.com/media/this-is-the-exit-end-of-a-pug-mill-which-prepares-the-plastic-clays-used-in.

  Figure 8. Latva-Somppi, A. Spraying glaze. (2020). [Photo].

  Figure 9. Kinnunen, A. (2020). Ceramic raw materials. [Photo].

  Figure 10. Kinnunen, A. (2020). Glaze examples. [Photo].

  Figure 11. McPartlan, M. (2020). Ceramic studio. [Illustration]

  
  

  
  

  
  

  
  

  
  

• Student Projects in Aalto University

• Art and Research in Ceramics
  Conducting research through practice, has a relatively long tradition in Aalto University. Ceramics has been part of this developing research field throughout its history in the School of Arts, Design and Architecture (previously known as Taideteollinen korkeakoulu), Aalto University. For supporting future work, we have here selected an example of art and research projects and suggested readings for getting insights on how ceramics has been contributing for creating new ways of understanding the world and culture we live in through the practices of art and research. The projects selected here are conducted within Aalto University, School of Arts and Design and Architecture in collaboration with a wider network of other stakeholders and partners. The selected reading suggestions are collected as a starting point to discover the practice and philosophy within ceramics.

  
  

  Selected Research projects in Aalto ARTS

  
  

  The selected projects show how wide the field of ceramics is and give examples of how ceramics can facilitate different platforms with looking into traditional hand crafted products in China to creating new business opportunities with the novel pairing of reindeer bone porcelain with clay 3D printing. In addition, clay as a natural material has a direct connection to soil: the ground we walk upon and through this, the topical issues of human traces in our environment can be elevated with the use of craft practices. The field of ceramics can also be used as a platform that connects different stakeholders from technology, museums, universities to individuals with the passion for ceramics.

  
  

  Traces from the Anthropocene: Working with Soil

  
  

  In the artistic research project Traces from the Anthropocene: Working with Soil, ceramic practitioners used methods of soil contamination research together with their skill and knowledge in the area of ceramic art to study anthropogenic contamination in the soil and sediments of the Venice Lagoon area. The project was carried out by craft researchers in the area of ceramic art from Aalto University in collaboration with soil contamination experts from the Finnish Environment Institute (SYKE). The research group consisted of craft researchers, ceramic artists and student-assistants. The project took place before and during the Research Pavilion event which was managed by Helsinki University of the Arts’ Academy of Fine Arts in the context of the 2019 Venice Biennale.

   

  First, the craft researchers gathered soil and sediment samples from sites which they selected according to existing environmental research of the Lagoon area.  The samples were carefully analysed for heavy metals in Aalto University’s Chemistry and Metallurgy Research Laboratory. Then, the craft researchers used their ceramics expertise when examining the soil materials. They grounded the contaminated soil and sediment samples into fine clay slips. The slips were fired onto sample pieces to help understand how the composition of soil affects the colour, surface or melting process. Then, they employed the soils as materials for artistic production: they used the slips as ceramic paints on large vessel forms built from clay from the local fields of Veneto.
  

  
  

  The research group worked for two months at the Research Pavilion. The vessel forms were built using the primitive coiling technique. The audience was invited to work with local brick clay alongside the artists. The samples, maps, research diaries, studio practice and work in progress formed a material narrative which was used to engage the audience in discussions about the environmental concerns. Also, a discursive event where soil contamination was discussed was organised. During the process of producing objects from soil materials which have been contaminated over the course of centuries, the artist-researchers contemplated how humans become with their environment and how the materiality of soil changes through human actions.

  
  

  
  

  Figure 1. Sediment sampling in Porto Marghera. Image: Pauliina Purhonen 2019.

  More information:

  https://www.researchcatalogue.net/view/474888/519616

  http://empirica.aalto.fi/projects/working-with-soil/

  https://www.designmuseum.fi/en/soil-matters/ 

   

  Related publications:

  https://www.researchcatalogue.net/view/697190/697191

  https://oajournals.fupress.net/index.php/aisthesis/article/view/10916

  
  

  24 Vases in 24 days: Vases created in Jingdezhen, the birthplace of porcelain in China

  
  

  Six design students and three teachers specialized in ceramics from Aalto University, Department of Design travelled to Jingdezhen, China, the source and birthplace of porcelain manufacturing in March 2018.

  Their task was to design and produce unique vases. The works were made on the spot during a 24 days workshop, in the ceramic studio reserved for visiting international artists provided by Jingdezhen Ceramic Institute. The students worked each on their own design, cooperating with local craftsmen: throwers, trimmers, kiln masters as well as porcelain painters. 

  The project was commissioned by Aalto Executive Education. 12 of the vases ended up in its art collection.

  
  

  
  Figure 2. Group of Aalto University students with their finished vases in front of the studio in Jingdezhen, China. Image: Priska Falin, 2018.
  

  Students: Saija Halko, Nikolo Kerimov, Matias Liimatainen, Maria Punkkinen, Collin Velkoff and Man Yau

  Teachers: Nathalie Lautenbacher, Priska Falin, Tomi Pelkonen

  Link for a documentary film presenting the working experiences in China, Jingdezhen during 2018:

  
  

  Ceramics and its dimension
  

  
  

  This European collaboration ran during the years 2014–2018 and was funded by the Creative Europe program. In this project, museums, universities and other stakeholders connected to the field of ceramics joined together to explore and show what ceramics has been and its future possibilities to a wider audience throughout Europe.

  Aalto University coordinated one of its 10 different sub projects called: Shaping the Future. This sub-project consisted of a student workshop in KAHLA porcelain factory, Germany, A touring exhibition and a publication.

  
  

  
  

  Figure 3. Work by: Babette Wiezorek, GER: The EXEX extruded extensions, 2016, porcelain, wood, 3D printed cylinders attached to precast objects in various sizes. Image: Chikako Harada, 2016.
  
  

  More information:

  http://futureceramics.aalto.fi/ 

  https://www.facebook.com/CeramicsEU/ 

  http://ceramicsanditsdimensions.eu/ 

   Some Interviews that were done during the project:

  https://www.youtube.com/channel/UCwUKlN9tjF9eNnUHYSkcx8g/videos

   Pdf version of the Shaping the Future publication can be downloaded here:

  https://aaltodoc.aalto.fi/bitstream/handle/123456789/25423/isbn9789526070414.pdf?sequence=1&isAllowed=y

  
  

  3DKERA

  
  

  3DKERA is a project that investigates the use of Reindeer bone china with 3D printing. The aim is to bring out new business opportunities in Finland. The basis for the project has been in developing the reindeer bone porcelain to be used in additive manufacturing processes such as extrusion 3D-printing and also more recently for the use of stereolithographic (SLA) printing where the ceramic materials are mixed with photopolymers.

  
  

  This project is collaboratively led by two different Schools in Aalto University: Department of Design in the School of Arts, Design and Architecture and Mechanical Engineering in the School of Engineering. The collaboration brings together the knowhow in material development in ceramics and the focus on developing the 3D-printers to suit the aims of the project as well the material needs.

  
  

  
  

  Figure 4. Clay 3D-printed objects that explore different shapes, materials and printing settings. Image: Nur Horsanali, 2019.
  
  

  More information:

  http://empirica.aalto.fi/projects/3dkera/ 

  Articles:

  https://www.aalto.fi/en/news/utilizing-local-reindeer-bone-waste-from-lapland-in-ceramics  

  https://www.sompio.fi/uutiset/3dtulostus-avaa-mahdollisuuksia-poronluun-paikalliselle-hyodyntamiselle-6.184.1730332.520a9839e8
  
  

  Reading suggestions

  
  

  In this list of selected readings, you can find books and articles as well some work done in Aalto University that are connected to ceramics. This is a small selection that gives you a starting point where you can begin your exploration. More publications produced in Aalto University can be found in Aaltodoc (aaltodoc.aalto.fi).

  
  
  

  Selection of Books about Ceramics

  
  

  Beittel, K. R. (1992/ 1989). Zen and the Art of Pottery. Weatherhill.

  De Waal, E. (2016). The White Road: Journey into an Obsession. Picador.

  De Waal, E. (2010). The Hare with Amber Eyes: a hidden inheritance. Random house.

  Elderton, L. & Morrill, R. (2017). Vitamin C: Clay + Ceramics in Contemporary Art. Phaidon.

  Kalha, H. (1996). Ruukuntekijästä multimediataiteilijaan: Suomalaisen keraamikon ammatillinen ja taiteellinen identiteetti. Taideteollinen korkeakoulu.

  Lautenbacher, N. (2020). Kantava maa -Solid Ground. Aalto ARTS Books.

  Leppänen, H. (2003). Ruukun runoutta ja materiaalin mystiikkaa: sata vuotta keramiikkataiteen opetusta ja tutkimusta. Taideteollinen korkeakoulu.

  Peterson, S. (1981/1974). Shoji Hamada: A Potter’s Way and Work. Kodansha International LTD.

  Richerson, D. W. (2012). The Magic of Ceramics. John Wiley & Sons.

  Stouffer, H. (2016). The New Age of Ceramics. Gingko Press.

  Sutherland, B. (2005). Glazes from Natural Sources. University of Pennsylvania Press.

  Examples of Doctoral dissertations
  in Aalto University, Finland

  
  

  Berg, A. (2014). Artistic Research in Public Space. Participation in material-based art. (aalto.fi)

  Groth, C. (2017). Making sense through hands : design and craft practice analysed as embodied cognition (aalto.fi)

  Mäkelä, M. (2003). Saveen piirtyviä muistoja: Subjektiivisen luomisprosessin ja sukupuolen representaatioita [Memories in clay: Representations of subjective creation and gender]. Helsinki: Taideteollinen korkeakoulu.

  
  

  Examples of Master's thesis
  in Aalto University, Finland
  

  
  

  Chen, T. (2020). Soil care: Symphony rehearsal (aalto.fi)

  Cortés Reina, C. (2019). Moving bodies (aalto.fi)

  Halko, S. (2019). Arkisto-sarja / Pohdintaa keramiikan piensarjatuotannosta (aalto.fi)

  Horsanali, N. (2019). Digitalization meets improvisation: Developing a personal way of dealing with the rising digital presence in design (aalto.fi)

  Huhtakallio, K-M. (2017). Hiljainen kertomus – [Oma]kuvia tunteista ja merkityksistä (aalto.fi)

  Kayis, E. (2017). Dialogue and compromise: Experimentation with ceramics in glassblowing process (aalto.fi)

  Luo, J. (2019). A shelf made of ceramic: material exploration of using ceramic in furniture design (aalto.fi)

  Ono, A. (2013). Fields of blue (aalto.fi)

  Pehkonen, L.  (2014). Fanfaari -keraaminen kollaasi (aalto.fi)

  Saarelainen, T. (2019). Kylässä - Journey of reflections on designer's identity (aalto.fi)

  Tolvanen, I. (2017). Food waste stories: Ceramic experiments (aalto.fi)

  Wang, M. (2015). Into surface (aalto.fi)

  
  

  Articles

  
  

  Berg, A. & Sirowy-Estkowska, B. (2012). The materiality of art in knowledge production [Paper presentation]. Art of Research 2012 conference: Making, Reflecting, Understanding. Helsinki, Finland.

  Bunnell, K. (2004). Craft and digital technology. Keynote speech. In: World Craft Council 40th Annual Conference, Metsovo, Greece. http://repository.falmouth.ac.uk/537/

  Elbrecht, C. & Antcliff, L. R. (2014). Being touched through touch. Trauma treatment through haptic perception at the Clay Field: A sensorimotor art therapy. International Journal of Art Therapy, 19:1 pp. 19-30. DOI: 10.1080/17454832.2014.880932

  Falin, P. & Oksanen, P. (In press). Ceramic pebbles as sensory tools: exploring the quality of muteness in tactile experience. Proceedings of Art of Research 2020 conference.

  Falin, P., Horsanali, N., Hansen, F. T. & Mäkelä, M. (In press). Practitioners’ Experience in Clay 3D Printing: Metaphorical viewing for gaining embodied understanding. Proceedings of BICCS2021 conference.

  Falin, P. (2014). Connection to materiality: Engaging with ceramic practice. Ruukku: Studies in Artistic Research, 2. https://doi.org/10.22501/ruu.44836

  Falin, P. & Falin, P. (2014). Making and Perceiving: Exploring the degrees of engagement with the aesthetic process. In: Y-k. Lim, K. Niedderer, J. Redström, E. Stolterman and A. Valtonen (Eds.) Proceedings of DRS2014: Design’s big debates, pp. 1612-1625.

  Groth, C., Mäkelä, M., Seitamaa-Hakkarainen, P. & Kosonen, K. (2014). Tactile Augmentation: Reaching for tacit knowledge. In: Y. Lim, K. Niedderer, J. Redström, E. Stolterman, & A. Valtonen (Eds.). (2014). Proceedings of DRS 2014: Design's Big Debates, pp. 1638-1654.

  Gürsoy, B. (2018). From Control to Uncertainty in 3D Printing with Clay. In Kepczynska-Walczak, A. Bialkowski, S. (Eds.) Proceedings of the 36th eCAADe Conference: Computing for a better tomorrow, pp. 21-30.

  Hansen, F. T., & Falin, P. (2016). 3D Printing as a Ceramic Craft Tool in Its Own Right. In M. Mäkelä, B. Schmidt, P. Falin and M. Juolahti (Eds.), Ceramics and its Dimensions: Shaping the Future (pp. 114–128). Helsinki: Aalto University.

  Hansen, F. T., & Tamke, M. (2019). A Visual Programming Interface as the Common Platform for Sharing Embodied Knowledge. In N. Nimkulrat, K. Kuusk, J. V. Noronha, C. Groth & O. Tomico (Eds.) Proceedings of EKSIG2019: Knowing Together: Experiential knowledge and Collaboration, pp. 56-70.

  Mäkelä, M. (2007). Knowing Through Making: The Role of the Artefact in Practice-led Research. Knowledge, Technology & Policy, 20(3), pp. 157-163.

  Mäkelä, M. (2016). Personal exploration: Serendipity and intentionality as altering positions in a creative process. FORMakademisk 9(1), Article 2, pp. 1-12.

  Sholt, M. & Gavron, T. (2006). Therapeutic Qualities of Clay-work in Art Therapy and Psychotherapy: A Review. Journal of the American Art Therapy Association, 23(2), pp. 66-72.

  
  

  Other useful books

  
  

  Adamson, G. (2007). Thinking through craft. Berg.

  Adamson, G. (2013). The invention of craft. Bloomsbury Academic/V&A Publishing.

  Adamson, G. & Bryan-Wilson, J. (2016). Art in the Making: Artists and their Materials from the Studio to Crowdsourcing. Thames & Hudson.

  Bennett, J. (2010). Vibrant Matter: a political ecology of things. Duke University Press.

  Ingold, T. (2013). Making: Anthropology, archaeology, art and architecture. Routledge.

  Malafouris, L. (2013). How Things Shape the Mind: A Theory of Material Engagement. The MIT Press.

  Ravetz, A., Kettle, A., and Felcey, H. (2013). Collaboration Through Craft. Bloomsbury.

  Sennett, R. (2008). The Craftsman. Penguin Books.

  Yanagi, S. (2013/1972). The Unknown Craftsman: A Japanese Insight into Beauty. Kodansha.

  
  
  

  
  
  

  
  

  
  

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