Ceramics (from the ancient Greek κεραμική (keramiké), female from κεραμικός (keramikós, ‘made of clay’), “ceramic”, which designated the potters’ quarter of ancient Athens, northwest of the Acropolis), is the art of making vessels and other objects from clay or other ceramic material by the action of heat, i.e. fired at a temperature above 900 degrees. The result is a diverse variety of pieces or objects made of terracotta – or “rough” pottery -, earthenware and porcelain. Besides naming the technique and its activity, it also gives name to the set of objects and production.
Its initial use was the manufacture of containers used to contain food or drink. Later it was used to model figurines of possible symbolic, magical, religious or funerary character. It was also used as a construction material in the form of brick, tile, or tiling, shaping walls or lining walls. The glazing technique increased its sumptuary attraction and architectural use. From the 19th century onwards, it was applied to industry as an electrical and thermal insulator in furnaces, in engines and in shielding. The modern ceramics is applied to the industries of silicates (group of minerals of greater abundance, since they constitute more than 95% of the terrestrial crust) and as complement in technologies of construction associated to the cement. It is also the base of the techniques of glazes on metal.
Basically it is the art of manufacturing objects made with fired clay. The clay is a sedimentary rock, constituted by aggregates of hydrated aluminum silicates, white when pure and varies in color according to the impurities it contains.
This art is one of the most important inventions of humanity. Being able to store and transport products, especially liquids, was a great revolution. As it is a lasting material, it is intimately related to the evolution of the human being, it can provide data about a certain people, degree of civilization, customs, religion, economy, commercial contacts… It serves as a testimony to know the characteristics of any culture.
The use of the ceramics is very varied but we will focus the study in its use for the domestic furniture.
The ceramics are a material that is used for a long time with utilitarian and decorative aims. It is obtained from different raw materials present in the form of powder or paste, which are kneaded or molded to give them the required shape and then subjected to a firing, so they acquire rigidity. Finally, the ceramic pieces can be painted with enamel.
In the elaboration of ceramic objects, inorganic solid materials are always used, such as silica, alumina, kaolin and metallic oxides, combined with other substances.
Ceramics are used in part because of their outstanding physical and chemical properties. Among them we can mention its stability, which allows it to avoid oxidation. It resists corrosion and abrasion, it does not present elasticity, it is not combustible and it is refractory.
The term ceramics comes from the ancient Greek word κεραμική (keramikḗ) female form of κεραμικός (keramikos) “burnt substance”, which designated the neighborhood of the potters of ancient Athens, and is the art of making objects made from baked clay.
Some periods of our civilization, such as the Stone Age or the Bronze Age, were so named because of the importance of the use of certain materials and, therefore, it is striking that there is no period known as “The Ceramic Age”.
The ceramics is one of the oldest industries of the planet, its invention dates from the Neolithic period (Age of Polished Stone), 12,000 B.C. to 7,000 B.C., when the first containers to store food and water appear, although tests of the primitive elaboration of ceramics have been found in the Upper Palaeolithic, approximately in the year 24,000 B.C. Small figures, of humans and animals, used for ceremonial purposes, were made of clay dried in the sun or around the fire.
Chinese porcelain tibor, decorated with flowers, from the ceramic entry of Franquihogar’s blogThe properties of all materials are dictated by the types of atoms present, by the types of union of these atoms. The structure and the type of union tell us what kind of properties a certain material has, in our case the ceramic materials.
Ceramics usually have a combination of stronger bonds called ionic (occurs between a metal and non-metal and involves the attraction of opposite charges when electrons are transferred from the metal to the non-metal); and covalent (occurs between two non-metals and involves the sharing of atoms). The strength of an ion bond depends on the size of the charge on each ion and the radius of each ion.
The greater the number of shared electrons, the greater the force of attraction, or the stronger the covalent bond.
These types of bonds produce a high level of elasticity and hardness, high melting points, low thermal expansion and good chemical resistance. On the other hand, ceramics are also hard and often fragile, which leads to fracture.
To obtain pieces of great resistance the clay must be submitted to different processes such as moulding, drying and firing.
In its origins the ceramics were modeled by hand, with different techniques such as pinching (first a clay ball is made, then it is pressed with the thumb from the center of the ball, with the other fingers on the outside. We squeeze the edges, slowly, to narrow the walls. Then we create the shape we want.
The figures made with the pinch technique must come out of a single clay ball, although you can add handles or additional complements 🙂
The colombin (long clay rolls of about the thickness of your thumb are used. A mass is formed that is squeezed, from the center towards the ends, turning with the palms of the hand. Then we use a circular base of clay and add the rolls to it).
The plate or iron (starting from a piece of clay we apply a pressure using a roller, then we cut the different pieces, taking into account their humidity so that we can join them, we reinforce the joints with a clay cord that we will weld with a barbotine).
It is believed that the Chinese were the first to use more advanced practices for firing objects, 1500 years before European countries.
The oldest of all is the terracotta, “terra cotta”, lll a century. C.,
The best known is the porcelain that was produced during the Tang Dynasty (618-907), and perfected during the Ming Dynasty (1368-1644), in the same period began to be exported to Japan and Europe.
The basic stages in the manufacture of ceramic products are:
Depending on the nature and treatment of the raw materials and the firing process, two large groups of ceramic materials can be distinguished: coarse ceramics and fine ceramics.
Porous or thick ceramic materials. They have not undergone vitrification, i.e. quartz is not melted with the sand due to the low temperature of the kiln. Its fracture (when breaking) is earthy, being totally permeable to gases, liquids and fats. The most important ones:
It is used for tableware and decorative objects and is cooked in two phases:
Unlike wood, it is a much safer material for construction.
It is highly stable, the water does not alter it in the slightest.
Resistant to corrosion and abrasion
It is not affected by chemicals, nor does it wear out from polishing.
Although during the firing it acquires hardness, the ceramic is a material that fractures under stress.
Once it has set, the ceramic remains fixed, it is no longer possible to shape it.
Ceramics in general resist high temperatures (in fact they are obtained in kilns at temperatures that exceed 1000 °C), but this property can be optimized by including aluminum, beryllium and zirconium oxide clays in the mixture. In this case, the firing is carried out at 1300-1600 °C and very slow cooling takes place. In this way, products are obtained that can resist temperatures of up to 3000 °C, necessary in quite specific uses.
In addition to temperature resistance, ceramic is characterized by its great power of electrical insulation.
The hardness of the ceramic is mainly given by its silicate or sand content, but this at the same time reduces its homogeneity; the fine grinding of the raw material helps in this sense.
The objects made in ceramics are part of many cultures of the world and are significant when it comes to reconstructing the customs of a civilization that has already disappeared, as is the case with pre-Columbian civilizations.
Thanks to their durability, many objects made in ceramics have been collected in different archaeological surveys and destined to daily activities (such as elements for cooking, for transporting water, etc.) or for use in special occasions, such as funerals, weddings, ritual celebrations and others.
Pottery can be intimidating to a novice, as it uses a lot of technical words and strange looking tools.
I started with it because of my wife, so I had a bit of an advantage.
Anyway, I hope this guide helps anyone taking their first steps in pottery.
But before buying ceramic materials, it is highly recommended that you check if there are classes or courses near where you live.
If you then get the pottery bug, you can start thinking about setting up your own workshop.
Before considering what equipment, you should purchase, it is worth thinking about the type of clay you should use.
Stoneware is in the intermediate range of firing temperatures.
Clay type stoneware
However, you must keep in mind that there are many types that vary in terms of the exact temperature at which they mature.
Stoneware is available in colors ranging from almost white to beige or red, and even with spots.
When the stoneware is fired until it matures, it is usually suitable for use in dishwashers and microwaves.
This makes it ideal for making tableware pieces: everyone loves cups!
Finally, porcelain is the ceramic that requires a higher firing temperature.
Keep in mind
If you plan to use it, you must make sure that your oven is capable of reaching the necessary temperature.
This is important, because many of the hobbyist ovens will not be able to reach it. Porcelain is a fine and beautiful ceramic that, due to its purity, can become transparent when it is thin enough.
It is also very expensive: more or less double than other types of ceramics.
【MAGNIFIC AND PRACTICE】 – Elegant appearance plus bright color.
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POWERFUL AND DURABLE: Professional heavy-duty portable ceramic wheel.
$399.99 at Amazon
Wide application]: this ceramic wheel machine is suitable for teaching ceramics.
45.90 in Amazon
If you are interested in turning, then you will need a ceramic lathe like the ones we compared.
If you don’t have much space, the best thing to do is to buy an electric winch like these.
Even the smallest model will be more than enough for a novice potter.
A more powerful one will only be necessary in case you are going to make really big vessels.
In my opinion, it is important that the lathe has a variable speed control.
Some lathes only have a system with a certain amount of speed increments.
It is important that the lathe can turn in the opposite direction in case it is easier for you to mold the pieces this way.
People who use standing lathes say they have a greater sense of control than using electric lathes.
This may be true, but I haven’t gotten around to using one of these lathes.
But I hope to be able to do it someday. Maybe when I have enough space.
When you are starting out, it is not necessary to buy too many ceramic materials. I still recommend a simple tool kit. For example:
Contains: sponge, metal crescent, large pourer, spatula, double-sided pourer, punch, thread and all the basics.
$8.15 at Amazon
Material: Made of quality stainless steel, the wooden handle is light, smooth and comfortable.
$29.99 on Amazon
When visiting a ceramic website or a ceramic materials distribution store, it is easy to get carried away.
However, the most important tools are your hands, and you should take care of them!
In fact, hands are great for producing naturally curved pots.
In my case, I make flat plates by pinching with my index finger and thumb on the edge.
This is a profile that would take a lot of time to perfect using tools.
That said, when it comes to buying ceramic materials, there are a handful of tools that I use on a regular basis.
You can start by looking at what I said about ceramic glaze, but roughly you can buy two types that I recommend.
Two-component acrylic-based polyol with a high degree of cure and aliphatic isocyanate
$35.90 at Amazon
Two-component acrylic-based polyol with a high degree of cure and aliphatic isocyanate
36.90 at Amazon
It is possible to elaborate some ceramic objects without glazing them.
For example, the flowerpots. However, most of the pieces must be glazed.
The enamel can give a glossy or matte finish, with all the points in between. In general, a glossy enamel is preferable for tableware because it is an easy to clean surface.
Some glazes can be tinted and still show some of the color of the clay body below. This can be good if you are using a ceramic with stains that you want to be seen.
The easiest way to glaze a piece is to buy ready-made powder from a ceramic material supplier.
There are many color options when buying ready-made glazes.
However, it is important that the firing temperature coincides with that of the clay, and that it is within the limits of your oven.
When you try a new glaze, 2 kilos of powder should be enough for you to immerse cups and other small objects.
As a starting point, a liter of water should be added for each kilo of powder.
Porcelain man mask
Wear a mask
In any case, whenever you work with ceramic materials such as powder glazes, you should wear a mask.
In addition, you should use a fine sieve to filter out the mixed glaze and remove any large particles.
Sieves are essential to achieve a glazing with a good finish.
Try to get a sieve that uses a minimum of 80 mesh. They are available at ceramic material stores.
I currently prepare my own glazes. However, when I was a beginner I used to buy ready-made powder glazes.
They are designed to produce results consistent with many types of clay and firing methods.
Since there are so many other things to learn when you start with ceramics, taking into account the chemistry of the glazes can be a bit excessive.
In my case, I make my glazes because I enjoy experimentation. Also, I have more control over color and texture, and it comes out cheaper.
However, some professional potters use ready-made glazes and get fantastic results.
In my case, on the lathe I mainly make bowls, so I have a ceramic cutter that is great for separating them when they are ready.
The wire is usually nylon or metal, with wooden handles at the ends to hold it.
A sponge is often used to moisten the bowl with water as it turns, in order to provide lubrication.
In addition, sponges with handles are useful for removing water from inside objects with narrow necks.
My favorite accessory to soften the edge of the bowls is a small piece of flannel.
You can buy large chamois from places that sell car cleaning supplies, and then cut them into smaller pieces.
When making flat plates or bowls, it is helpful to use a wooden shape to soften the base.
Punches are great for cutting off the top of wobbly bowls, or for poking out air bubbles. Thin punches are better than thicker ones.
A modelling stick allows to clean the external part of the bowls, and to make a bevel at the base. This bevel makes it easier to cut the bowl to separate it from the lathe.
To make bowls with ring-shaped bases, an emptying device is necessary. This tool is used to refine the shape when the clay has become firmer.
The main accessory needed is a ceramic oven (look at the ones we have recommended).
If you are only interested in making decorative elements or models, you can use polymer clay or air-drying materials.
If you plan to make pieces of a dinner service, vases or other objects that must be resistant, it is vital to use an oven.
Some potters use wood or gas ovens. However, in this guide I will focus on electric ovens, which are best suited for beginners.
Most small electric kilns reach a maximum temperature of about 1280°C.
Smaller ovens can be transported more easily, and can be plugged into a standard outlet.
However, larger ovens require the intervention of an electrician.
Furthermore, with smaller ovens you can bake more often.
The reason for this is that it does not take long to accumulate enough pieces to fill the oven and to bake efficiently.
In my case, I bought my oven on Ebay. At that time I was a novice and didn’t know much about ceramic materials.
If I remember correctly, I paid about 150 euros for an old oven.
I was lucky and the oven was in a pretty good state.
Its internal measurements are 35 centimeters in diameter and 60 centimeters in height.
Sometimes I wish it were smaller so I could bake more often.
The most important thing to take into account in a second-hand oven is the state of the refractory bricks and the different elements.
Normally, in a second-hand kiln there will be some wear and tear. However, if there are major cracks in the lid or base, or elements hanging out of the bricks, then this is cause for alarm.
Ovens wear out over time.
Each baking degrades the elements, which in the end must be replaced.
On the other hand, buying a new oven is similar to buying a new car: you have something shiny that you know has never been used improperly.
However, spending thousands of euros was not an option for me, and my oven still works well after four years of occasional use.
Because of the extremely high temperatures they reach, the ovens need to be placed in a garage or an outside building.
In addition, you must take the necessary precautions and remove any flammable materials that may be around.
There are many different methods for making ceramic objects.
Sheet metal modeling
Some people make very beautiful objects with a professional finish from clay sheets.
These sheets can be molded to form cylinders, or they can also be placed in molds to form plates or bowls.
The clay sheets can be made by hand or, if many are needed, a laminating machine can also be used.
Clay slurry mould
On the other hand, ceramics can also be made with molds using a watery mixture of clay called barbotine.
Barbotine clay is a muddy or almost liquid consistency, used in pottery to join parts of a ceramic piece previously elaborated
The molds can be purchased at ceramic material stores.
They can also be made with plaster in case a special design is needed.
A potter’s wheel can be used to turn the clay into an infinite number of shapes.
It takes some time to learn the necessary technique. However, once mastered, it is a very efficient method.
Potter’s lathes can be electric or moved by the potter’s leg.