Clay products at home. Milk firing of clay products

To give clay products additional properties, they are exposed to high temperatures - firing. But the technology of firing clay is quite complex and resource-intensive, so I will try to talk about some of the nuances that you may encounter.

Preparing for firing

Before firing the product, it must be thoroughly dried for 2 to 7 days, depending on the size of the product. The product should be dried away from heating devices, direct sunlight, and drafts - that is, to exclude any sudden changes in the environment in which the product is located. At room temperature and in a dark, dry place, the product will dry evenly.

If the product dries unevenly, the product may crack and its small parts may simply fall off. Insufficient drying will lead to defects during firing. It is impossible to overdry the product.

After the product has dried, you need to carefully inspect it for cracks. If there are any, you can try to cover them with liquid clay, but this does not guarantee the safety of the product during firing. The best option is to prevent cracks from appearing, and this is achieved with high-quality modeling and proper preparation of the clay.

Be sure to check the sound of the whistle - if it disappears or becomes dull, then it is not too late to try to fix everything.

In some situations, during drying, a spider may settle in the products (there was a case when it took a fancy to one of my whistles), in which case it needs to be moved to a safe place .

The final stage of preparation will be sanding the product. When sanding, fingerprints, various crumbs and bumps can disappear, and the product will acquire a noble appearance. Sanding can be done with small sandpaper.

Conditions for firing

Temperature. The most important thing in firing is a gradual increase in the firing temperature and gradual cooling of the product after firing. In the first two hours, the temperature should not exceed 400 degrees. The temperature range should be between 300-900 degrees Celsius. At lower temperatures, firing will be insufficient and the product will not acquire the necessary properties. At high temperatures, the product can be completely destroyed.

Duration. Depending on the size of the product and the firing method, the duration of the process can vary from 8 hours to several days. Very small items can be fired in a minimum amount of time.

Composition of the material. The firing technology largely depends on the composition of the clay. Natural clay contains an admixture of sand, and the less sand, the lower the firing temperature. In my practice, there have been cases when purchased powdered clay literally boiled at 750 degrees and dried out in the form of a porous sponge. The product was completely destroyed. The clay should not contain stones or air. If the material is not homogeneous, a rupture will occur. Since materials of different densities will expand differently with temperature changes.

The quality of the sculpt. The main requirement for modeling is the absence of air bubbles in the product. As the temperature rises, the air will expand and seek a way out, tearing the product. Therefore, when covering cracks and fastening parts of the product, eliminate the possibility of the formation of air capsules.

Firing methods

Firing in a muffle furnace. There are several methods of firing clay products, but the most common is firing in a muffle furnace. This is an electric oven equipped with a temperature control mechanism.

Modern kilns have automatic firing programs for various types of products, a window for viewing the status of products, and other options. Another important characteristic of a muffle furnace is the volume of the chamber. Some swords have a cylindrical chamber that can only accommodate small items, while there are large kilns for firing pottery and sculptures.

Firing over a fire or in a non-electric oven. This is a rather non-trivial task, primarily due to the fact that it is not possible to completely control the temperature. In addition, the stove is rarely heated for eight hours, and it’s difficult to sit by the fire for a third of the day. However, if you do get ready, place the product in a container with sand - this will smooth out the sharp increase in temperature.

Firing at home. You can also fire a clay product on a gas or electric stove, but I warn you - this is quite dangerous and the quality of the firing will still be far from ideal. To do this, you can take a cast-iron frying pan with dry washed river sand and put it on the fire. You need to carefully place the product on top and cover it with a fireproof container - a clay pot or pan. The process must be supervised and the room should be regularly ventilated so as not to cause overheating and oversaturation of the air with toxic gases.

Why is firing necessary?

During the firing process, the clay gets rid of almost all moisture, so the product becomes much lighter. In addition, clay elements are sintered and transformed into a single ceramic ingot, which is resistant to deformation and moisture penetration. Hence the whole need for firing.

The fired products are ready for painting, and after painting, for use.

This is important to know

After firing, the clay is not suitable for modeling, since it is no longer clay, but ceramics.

Firing can be done several times, gradually increasing the maximum temperature to achieve optimal results and gain experience.

After the main firing, the product can be coated with a special composition and fired again. When the composition melts, it forms a glaze.

During the drying and firing process, the product may be deformed and ultimately become smaller than planned. Therefore, when creating a product, you need to take into account the composition of the clay and the purpose of the future product. Clay with a high sand content is less susceptible to compression.

During the firing process, organic compounds will burn out (especially in natural clay) - this can lead to unpleasant odors. It is necessary to be able to ventilate the room.

The readiness of the product can be determined by weight, color and sound. After firing, any colored clay turns red. If it turns black, the product has overheated; if it has not changed color, it has not been burned enough. Fired products have a lighter weight and a ringing nature. However, when fired, whistles can completely lose sound (irreparably) or, on the contrary, be transformed.

In any case, correct firing of clay products can only be achieved with experience. So go for it and good luck!

Preface. From the history of pottery.

The most ancient books include clay tablets Sumerians. They were found at the site of an ancient settlement in the lower layers of the cities of Ur and Kish, which existed around 3500 BC. In the 25th century BC. (photo from the site: demsvet.ru)

In ancient times they wrote on thin clay tablets in the same way as they write on paper now. By the way, white clay is necessarily included in modern paper. This means that to some extent we are still writing on clay. Among the clay tablets found during excavations there are all kinds of documents: laws, certificates, business reports. Clay tablets became the pages of the very first books written by ancient authors. After completing the inscriptions, some tablets were only dried well in the sun, while others, more valuable, intended for long-term storage, were burned.

Since time immemorial, people have sculpted from clay objects necessary for everyday life, primarily dishes. Only dishes made from unfired clay are very fragile and are also afraid of moisture. Only dry foods could be stored in such containers. While raking up the ashes of a dying fire, the ancient man more than once noticed that the clay soil in the place where the fire burned became hard as stone and was not washed away by rain. Perhaps this observation inspired a person to burn dishes at a fire. Be that as it may, clay baked in a fire was the first artificial material in the history of mankind, which later received the name ceramics. With the development of technology, molded and dried clay products began to be fired not in fires, but in special furnaces - forges.

Clay pithos, Taman Archaeological Museum. (photo from the site: showbell.ru)

Many clay objects have reached us in their original form. This is primarily a variety of dishes, lamps, children's toys, religious figurines, casting molds, sinkers for fishing nets, spindle whorls, thread spools, beads, buttons and much more. In the hands of talented craftsmen, ordinary things turned into true works of decorative and applied art. The art of ceramics reached high development in Ancient Egypt, Assyria, Babylon, Greece and China. Many museums around the world are decorated with dishes made by ancient potters. The old masters knew how to sculpt dishes that were sometimes gigantic in size. Impresses with high technical skill Greek pithoi- vessels for water and wine, reaching a height of two meters.

In our time, many of the secrets that the ancient masters possessed have been lost. Despite the high development of production, modern ceramists have not yet been able to uncover the secret of preparing the glaze that covers two large vases discovered during excavations by Chinese archaeologists. When water was poured into the found vases, the glaze immediately darkened and changed color. As soon as the water was poured out, the vessels regained their original whiteness. Although these amazing chameleon vases were created by Chinese potters more than a thousand years ago, they have not lost their amazing properties. Ancient Rus' was also famous for ceramics. Russian potters painted tableware with special ceramic paints or engobes (liquid colored clays) and covered them with glassy glaze. Especially a lot of black-polished dishes were made. Slightly dried items were rubbed to a shine with a polish (smooth stone or polished bone), and then fired over a smoky flame without allowing oxygen into the forge. After firing, the dishes acquired a beautiful silver-black or gray surface, at the same time it became more durable and less permeable to moisture.

. In the village of Zhbannikovo, Gorodetsky district, Nizhny Novgorod region, there is an interesting craft - making whistles from clay in the form of birds, lambs, and goats. This is a very ancient type of toy. (photo and signature from the site: s30893898787.mirtesen.ru,

In modern urban housing, clay is also present in the form of all kinds of facing slabs, bathtubs, and sinks. In a word, clay is always a modern material, without which it is impossible to do without either in the present or in the future. Since ancient times, clay has served man.

Clay. Preparing clay for work.

Clay- fine-grained sedimentary rock, dust-like when dry, plastic when moistened. Clay consists of one or more minerals of the kaolinite, montmorillonite or other layered aluminosilicates (clay minerals) group, but may also contain sand and carbonate particles. It is formed during the local accumulation of minerals, but most of them are sediments from water flows that fall to the bottom of lakes and seas.

The main source of clay rocks is feldspar, which, when decomposed under constant exposure to atmospheric conditions, forms kaolinite and other aluminum silicate hydrates.

The clay found in nature is so diverse in composition that in the depths of the earth you can actually find a ready-made clay mixture suitable for making any type of ceramics - from sparkling white earthenware to red stove bricks. Of course, large deposits of valuable types of clay are rare, so factories and plants for the production of ceramics arise near such natural storehouses, as, for example, in Gzhel near Moscow, where white clay was once discovered.

You can find suitable clay for modeling and pottery almost anywhere, if you wish. In addition, a small amount of clay can always be “corrected” by elutriation and other methods. Clay may lie immediately below the soil layer at a shallow depth. In garden plots it can be found during various land works. Layers of clay quite often come to the surface along the banks of rivers and lakes, in slopes and slopes of ravines. In the Non-Black Earth Region there are areas where clay is literally underfoot and in wet weather on country roads it turns into a solid mess, causing indignation among passers-by. Even from such “dirt” collected on the road, small decorative items can be sculpted and then fired. But, of course, this should not be done. Even where there is clay soil all around, you need to dig at least a shallow ditch to get to cleaner and more uniform layers.

You can determine the suitability of clay for modeling in a fairly simple way. From a small lump of moistened clay taken for testing, roll a rope between your palms about the thickness of your index finger. Then slowly fold it in half. If at the same time no cracks or very few of them form at the bend, then the clay is quite suitable for work and, in all likelihood, it contains 10 - 15% sand.

Clay containing less than 5% sand is considered oily, while lean clay contains up to 30% sand. Medium fat clay contains 15% sand.

Each type of clay changes its color at a certain stage of modeling, drying and firing. Dried clay differs from raw clay only in a lighter tone, but when fired, most clays dramatically change their color. The only exception is white clay, which, when moistened, acquires only a slight gray tint, and after firing remains the same white. The color of “living clay,” which is usually in a wet state, is most often deceptive. After firing, it can unexpectedly change dramatically: green will become pink, brown - red, and blue and black - white. As you know, craftswomen from the village of Filimonovo, Tula region, sculpt their toys from black and blue clay. Only after being dried in a kiln do the toys become white with a slightly creamy tint. The miraculous transformation that occurred with the clay can be explained very simply: under the influence of high temperature, organic particles burned out, which gave the clay a black color before firing.

The color of clay, both in the raw and fired state, is also influenced by various mineral impurities and metal salts contained in it. If, for example, the clay contains iron oxides, then after firing it turns red, orange or purple. Based on the color that the clay acquires after firing, there are white-burning clay (white color), light-burning clay (light gray, light yellow, light pink color), dark-burning clay (red, red-brown, brown, brown-violet color).

To determine what type of clay you are dealing with, make a plate from a small piece or roll it into a ball, which, after thoroughly drying, is fired in a muffle furnace.

Place the prepared clay in containers and fill it with water so that individual lumps protrude slightly above the surface. It is advisable to immediately prepare as much clay as possible. When there is an abundance of clay, only a small part of it is consumed, and the rest will be constantly aged. The more the clay is kept wet, the better.

Previously, potters kept clay in the open air in the so-called clay pit - a special pit, the walls of which were made of logs, blocks or thick boards. The clay had to lie in the clay pot for at least three months, but sometimes it was in open storage for several years. In spring and summer it was burned by the sun's rays, in the fall the winds blew and rained, in winter it froze in the cold and thawed during the thaw, then melt water penetrated into it. But all this was only beneficial for the clay, since it was loosened by numerous microcracks, while harmful organic impurities were oxidized and soluble salts were washed out. The centuries-old practice of folk craftsmen has shown that the longer the clay is aged, the better its quality.

The clay, which has the optimal fat content and has aged well, just needs to be thoroughly kneaded and the pebbles that accidentally fall into it should be selected. In the past, clay was kneaded in a pottery or hut on the floor sprinkled with sand, which is called “topanets” in the riddle about the pot. Often the whole family, including children, was involved in kneading and cleaning the clay. The clay was trampled with bare feet until it turned into a thin plate, which was immediately rolled into a roll. The roll was then folded in half and trampled again. When the clay regained the shape of a plate, a new roll was rolled up. This was repeated up to five times until the clay turned into a homogeneous mass, soft and pliable, like pie dough. By the way, well-washed and cleaned clay, ready for pottery work, is called clay dough.

Sifting clay.

If you decide to sift the clay, then spread it in small lumps on a wooden floor and dry it in the sun (Fig. 1.1). In winter, the clay dries well in the cold, spread out under a canopy where snow does not fall. A small amount of clay can be dried indoors, on a warm stove or on a central heating radiator. Of course, the smaller the lumps, the faster the clay will dry. Pour the dried clay into a thick-walled wooden box and break it with a tamper - a massive piece of tree trunk with handles reinforced on top (Fig. 1.2). Sift the resulting clay dust through a fine sieve and remove from it all kinds of impurities in the form of pebbles, chips, blades of grass and large grains of sand (Fig. 1.3). Before modeling, the clay powder is kneaded in the same way as bread dough, adding water from time to time and thoroughly mixing the clay mass with your hands. It is advisable to store some of the clay powder in case the clay dough needs to be quickly made thicker, but there is no time for drying and evaporation. Add the required amount of powder to the liquid clay dough and then knead well.

Clay preparation. Sifting and elutriation. (picture from the site: poselenie.ucoz.ru)

Elutriation of clay.

When elutriated, the clay not only becomes purified, but also becomes fattier and more flexible. Therefore, clay that contains a lot of sand and has low plasticity is most often elutriated. You need to soak the clay in a tall vessel, such as a bucket.

Pour one part clay with three parts water and leave overnight. In the morning, thoroughly stir the clay with a stirrer until a homogeneous solution is obtained. Then let the solution sit for a long time. As soon as the water clears from the top, carefully drain it using a rubber hose. But it is not so easy to drain the water without muddying it. Therefore, even in ancient times, a simple and ingenious device was invented, which is still used by Japanese potters (Fig. 1.4). Several holes are drilled vertically in a wooden tub at a short distance from each other. Before filling the tub with liquid clay mortar, each hole is plugged with a wooden stopper. Heavier grains of sand and various kinds of pebbles settle to the bottom first. Then, after settling, clay particles fall down. Gradually, the water from above brightens and finally becomes transparent (Fig. 1.4a). As soon as the level of light water seems slightly below the top hole, the plug is pulled out, and the clarified, settled water is poured out of the barrel (Fig. 1.46). After some time, remove the plug located below. This way all the settled water is gradually drained out. To speed up the process of clay settling, bitter Epsom salt is first added to the solution (about one pinch per bucket). Instead of a wooden tub, you can use a suitable metal container. At different levels, short tubes are soldered into it and plugged with plugs.

After removing the settled water, carefully scoop out the liquid clay, leaving the bottom layer untouched, which contains pebbles and sand that have settled to the bottom. Pour the clay solution into a wide wooden box or basin and place it in the sun so that excess moisture evaporates from the clay faster (Fig. 1.5). As soon as the dried clay loses its fluidity, stir it with a shovel from time to time. After the clay acquires the consistency of thick dough and stops sticking to your hands, it is covered with plastic film or oilcloth and stored until the start of modeling work.

Working with clay. Clay crafting.

Kneading" clay.

Immediately before modeling, in order to remove air bubbles from the aged clay and increase its uniformity, the clay dough is beaten and kneaded. Breaking clay is indispensable in cases where the clay, for some reason, has not been cleaned well enough and there are small pebbles and other foreign inclusions in it. Processing begins by rolling a piece of clay into a bun (Fig. 2.1), which is then lifted and thrown forcefully onto a table or workbench. In this case, the bun is slightly flattened and takes the shape of a loaf. Take a pottery string in your hands (steel wire with two wooden handles at the ends (Fig. 2.2)) and cut the “loaf” into two parts (Fig. 2.3). Having lifted the top half, turn it over with the cut side up and throw it forcefully onto the table. The lower half is also thrown onto it with force, without turning it over (Fig. 2.4). The stuck halves are cut from top to bottom with a string, then one of the cut pieces of clay is thrown onto the table, and the second one is thrown onto it (Fig. 2.5). This operation is repeated several times. When cutting clay dough, the string pushes out all kinds of pebbles encountered along the way, opens voids and destroys air bubbles. The more cuts you make, the cleaner and more uniform the clay dough will become.

You can also process clay dough using a carpenter's plow or a large knife (Fig. 3). The lump of clay is carefully compacted using a massive wooden mallet (Fig. 3.1). Then it is pressed forcefully against a table or workbench and the thinnest plates are cut off with a plow (Fig. 3.2a) or a knife (Fig. 3.26). All kinds of foreign inclusions that fall under the blade are thrown aside. The thinner the slices are cut, the cleaner and more uniform the clay dough becomes. The plates obtained after planing are again collected into a single lump and compacted with a mallet until it becomes monolithic (Fig. 3.3). The lump of clay prepared in this way is planed again. These techniques are repeated until the clay dough becomes homogeneous and plastic.

Shift the clay.

This is the last stage of preparing clay dough intended for modeling. Take a lump of clay in your hands (Fig. 4.1) and roll it out so that you get an elongated roller (Fig. 4.2). Then the roller is bent in half (Fig. 4.3) and crushed so that it again forms a rounded lump (Fig. 4.4). From this moment on, all miner operations are repeated in the same sequence several times.

If the clay is too dry, it is generously sprinkled with water before each subsequent shift.

Determine the plasticity of clay in a way already known to you. A small lump of clay (Fig. 4.5a) is rolled out between the palms (Fig. 4.56). The resulting tourniquet is bent in half. If the clay has high plasticity, then not a single crack will appear at the bend of the rope (Fig. 4.5c).

The presence of cracks indicates that the clay is too dry and needs to be moistened (Fig. 4.5d).

There are many folk ways of preparing clay dough. In some regions of Russia, toy makers knead and then separate the clay into separate pieces in the following way. The clay lump (Fig. 5.1) is flattened with a wooden hammer (Fig. 5.2). The resulting plate is rolled into a roll (Fig. 5.3). The roll is crushed with a hammer and molded into the same lump that was at the very beginning (Fig. 5.4). The molded lump is flattened again (Fig. 5.5) and the plate is rolled into a roll (Fig. 5.6). Having done all this several times, the roll is thoroughly kneaded and a tourniquet is rolled out of the resulting lump, which is cut into “slices” with a knife (Fig. 5.7). Each “piece,” depending on the size of the future workpiece, is cut in turn into two or four parts (Fig. 5.8). Each half and quarter is rolled out in the palms, obtaining blanks in the form of balls of the same size (Fig. 5.9). The blanks are placed in a wooden box, covered first with a moistened cloth, and then with oilcloth or plastic film. Sometimes they are placed in some kind of metal container with a lid on top. In this form, the blanks can be stored for more than a month without losing their original plasticity.

Drying clay products.

Drying- a rather lengthy process. Haste can negate all previous work: when drying quickly, the product becomes covered with numerous cracks and warps. At the first stage of drying, moisture from the product should evaporate as slowly as possible. In the first days, folk craftsmen dry dishes and toys indoors or under a canopy in a quiet, windy place where there are no drafts. Pre-drying takes two to three days. After this, the products were dried in a heated oven. The better the clay dries, the greater the hope that there will be no defects during firing.

A product that has a complex shape with many details must be dried with extreme care, for example, by placing it in a metal container or box, covering it with a sheet of newspaper on top. A large product can be covered on top with a dry cloth. On the second day, remove the rag, but continue to dry the product in the shade. On about the fourth day, a medium-sized product can be dried on a stove or on a central heating radiator. Dried clay acquires sufficiently high strength necessary for further processing. Before firing, each product must be carefully inspected. If cracks are found, they must be carefully repaired. The crack is moistened with water and covered with soft clay. In addition to cracks, the product may contain all sorts of irregularities, accidental deposits, clay chips adhering to the surface and small scratches. Damaged areas should be treated with a scraper and cleaned with fine-grained sandpaper, and then remove clay dust with a wide brush or broom.

To give the product shine, polishing is used. One of the ancient methods of polishing is very simple. The surface of the dried product is rubbed with any smooth object, compacting the top layer of clay until shiny.

After firing, the shine becomes stronger. Polished dishes can be safely used in the household, as they are quite moisture resistant. In Rus', polished dishes were additionally subjected to blackening for decorative purposes. To do this, at the end of firing, some kind of smoking fuel, for example, var, was thrown into the furnace. Absorbing smoke, the vessels turned black, retaining their shine. There is another way to blacken dishes. Heated ceramics are thrown into sawdust or chopped straw.

Firing clay.

Since ancient times, potters have built their clay kilns on a small slope. You can see approximately what it looked like in the figure in which the forge is drawn in section.

Schematic diagram of a furnace for firing clay, sectional, side view.

Modern clay firing technologies mostly use electric muffle and various chamber furnaces, which easily reach temperatures of 950 degrees or higher.

Electrical laboratory muffle furnace wide purpose. Maximum temperature up to 950°C. Power 1 - 1.5 kW. Loading a muffle with a volume of up to 10 liters. Such stoves can be successfully used in an ordinary city apartment.

Firing technology.

The maximum firing temperature for simple products is 950°C. Higher temperatures are used for earthenware (up to 1250°C) and porcelain (up to 1420°C). The product cannot be fired immediately at this temperature; it must be raised gradually, smoothly, without allowing jumps, by about 100°C per hour. Thus, in the first two hours, the temperature in the oven should reach 300°C and it should also be gradually raised to 500°C. It is 500°C that is the critical point - at this temperature even very well-dried clay products can crack. Still smoothly and gradually, the temperature should be raised to 950°C. During firing, do not open the viewing window in the kiln.

Again, it is necessary to lower the temperature in the oven gradually, without jumps. The rate of temperature decrease should not exceed 60°C per hour and only when the oven reaches 400°C can the temperature decrease rate be slightly accelerated. It is allowed to take out the finished product at 60°C, and if the product is covered with glaze - at 40°C. Moreover, the finished products should be placed in dishes specially prepared for this purpose.

But what should someone do who just wants to mold a rectangular parallelepiped out of clay and fire it? Then raise it above your head and proclaim: “I made a brick!”? This is what “other technologies” are for.

After firing, the clay becomes ceramic, but this happens at a temperature of 500-900°C, that is, the clay must be placed in a place where it is at least 500°C. The duration of firing depends on the temperature - the lower the temperature, the longer the clay needs to be fired. But it will still take at least 8-12 hours to fire the clay.

When the clay has become ceramic after firing, it can be additionally coated with glaze and fired again.

Roasting at the stake.

The product must be heated on all sides, otherwise you will hear clicks from explosions (it is better not to sit children nearby, in case a fragment will fly off), this practice is possible with this method. Successful results are obtained with small-sized products, whistles, but you still have no guarantee that you will save each of them. (photo and signature from the site: glina.teploruk.ru)

A regular fire can reach temperatures of 750°C, which is quite similar to the temperature at which clay turns into ceramics. When firing at a fire, the rules for firing in a kiln apply, namely, the product must be fired equally, evenly on all sides. To do this, you can surround the product with firewood and make a fire around it. In general, that's all! If you keep the fire going for 8 hours, or better yet, even longer, the product will be completely cooked and will be quite strong. The longer the firing takes place, the stronger the finished product will be. Before starting a fire, the clay product can be placed on some elevation, otherwise all the heat may be on top of the product.

You can check the quality after firing by the color and sound of the finished product. If the product looks burnt, has changed colors, or has black spots, the firing took too long. If, upon impact, the product makes a dull sound, the firing time was not enough and the product did not turn into ceramics, but remained clay.

Roasting under the fire.

To fire clay under a fire, you should put the finished dried clay product in some container - a tin can, for example, can be very suitable for this. Dig a hole and place firewood in it so that it resembles a lattice. Place the prepared containers (tin cans) with clay products in the cells of a lattice made of firewood. Fill the hole with coals so that they completely cover the containers (tin cans). For this, it is quite possible to use coals from an old fire. Sprinkle a thin layer of earth on top. In general, the clay kiln is ready.

All that remains is to build a fire on top of this pit and use it at your own discretion, so to speak, for your own pleasure. You can cook lunch and dinner or dry clothes and warm up, you can even just look at the burning fire and relax - the stove is working. With this technology, the stove continues to work even after the fire stops burning. For example, if the fire is extinguished late in the evening, then it should be covered with earth and left until the morning. At night, the clay products will gradually and smoothly begin to cool, which makes this technology for firing clay in some ways even more technologically advanced than conventional firing over a fire. In the morning, only ashes will remain from the coals with which containers with clay products (tin cans) were filled, and the products themselves will become completely solid and ready for further use.

Large items, such as jugs or wide plates, are unlikely to be fired using this technology, but it is very suitable for small items. This could be, for example, some souvenirs or decorations, or it could be very specific products - arrowheads, small gears, or something else.

What happens to clay during firing during heating and cooling.

(table data from the website: www.horss.ru)

1. Where do you get clay?
- Clay for modeling can be bought in stores that sell creative materials. Clay is also sold on the Internet; you can use a search engine to find such stores. As for the Moscow region, clay is available in Gzhel and it costs less there. In Moscow, for example, this is a store for ceramists, Horses, on Ul. Verkhnyaya Maslovka, 18 or Vorontsovsky plant, St. Architect Vlasov, 57

2. Is it possible to dig up clay from a quarry and use it for modeling?
- It’s possible, but to do this, the clay must first be cleaned of impurities (for example, small pebbles). To do this, the clay is diluted in water to the consistency of sour cream and filtered through a fine-fine sieve (coffee filters work well). Then the clay is poured onto gypsum slabs (you can make them yourself or buy them in specialized stores, such as Horse) and it is “pulled” - the gypsum absorbs excess moisture, and the dried clay is easily removed from the slabs and can be used for modeling. If there are no gypsum boards, then you need to let the clay settle and drain excess water from above. Then you need to wait until the clay dries to the point where you can sculpt from it. With gypsum boards, clay dries much faster.

3. Is it possible to fire clay in the oven or microwave? or do I need a special oven?
- It’s impossible, because firing requires a temperature of about 1000 degrees. The oven only heats up to 250. A microwave won’t work either, you need a special oven.

4. Is it possible to install a kiln at home?
- Maybe a small one. This could be a laboratory muffle furnace made at a factory. Or assembled by a stove maker according to your individual dimensions. Potters usually know good stove makers and can be recommended by craftsmen. But we must also take into account that it is not useful to breathe in the fumes that are released during firing and it is still better to use a separate room for the kiln, preferably with an exhaust hood.

5. Is it possible to work at home on a pottery wheel?
- You can, if you don’t feel sorry for the apartment, or rather the renovations in it. Because the splashes will fly from the circle in different directions, no matter how carefully you try to twist it. Although many craftsmen keep a circle at home, having allocated a special corner for it or protecting the apartment with oilcloths and curtains.

6. Is it possible to make a product on a pottery wheel the first time?
- Completely on your own - unlikely. But with the help of a master, you will definitely make your first work that you can use. It may be crooked, but this will only give it additional charm.

7. Is it possible to make a lid for a teapot to replace the broken one?
It is possible, but quite problematic, since clay shrinks by 8-10% during drying, which means it will be difficult to determine the size. It's faster and easier to make a new kettle.

8. Is it possible to immediately fire a freshly molded product?
No, the product must first be completely dry. Under natural conditions, this happens for 5-7 or more days (up to a month for large products) and only then can it be fired. If you put a raw product in the oven it will explode

9. What should you do if your cat’s ears fall off after drying?
Depends on what clay you made it from. Some clays allow you to slightly wet the place where you need to glue the ears and the ears themselves and try to apply them. If this number does not work with your clay, you can fire it and after firing, glue it either to glaze or to silicate glue, if you do not plan to fire with glaze. And in the future, even when sculpting, try to carefully glue the parts onto water or onto a slip - this is what liquid clay is called.

10. Is it possible to repair a crack in a ceramic product?
Depends on the crack. If this is a micro crack, then it is likely that it will disappear under a layer of glaze, but it may, on the contrary, become even larger. This will become clear after firing with glaze. If you do not plan to glaze the product, but want to paint it with acrylic paints, you can fill the crack with plaster and then paint it with acrylic. Plaster can be used to seal a crack of any size. Products coated with acrylic paints cannot be used for food purposes.

11. Is it possible to pour water into ceramic products (vases, mugs) that are not covered with glaze?
Ceramics is a porous material and will allow water to pass through without additional treatment. That is why it is covered with glaze. Also, ceramics can be boiled in milk at a temperature of approximately 350-380 degrees, the milk burns out and clogs the pores, so the product stops letting water through and acquires a dark shade. This method was invented even before the invention of glazes, it is called milking.

From which our ancestors made a lot of useful household items. Later, jewelry for women began to be made from this material. Its color range can be very diverse: red, brown, gray, white, blue, yellow and combined combinations. It depends on its mineral composition. Now, in order to get clay, you don’t necessarily need to go looking for it in places where it accumulates. It is enough to contact any specialized store or creative laboratory. It is important to note that not any clay can be suitable for its creative embodiment in an object of art or everyday use.

How can clay be useful?

Any activity that involves a combined interaction of manual labor and imagination not only captivates the mind of the master, but also helps the young body develop fine motor skills of the fingers. This means that thinking, imagination, sense of color, geometry of an object and much more will give the child the opportunity to develop his creativity. In addition, it is well known that modeling has a calming effect and makes it possible to focus on a specific subject - “here and now.” And a gift made with your own hands and from the heart will not leave anyone indifferent.

Firing clay at home

If you want to give your handicraft a long life, then firing is simply necessary. To prevent the product from losing its shape or cracking during this process, it is very important to follow the clay firing technology in accordance with its standards. Due to the exposure of clay to high temperatures, the product gains strength and “petrifies”. And if after all the required manipulations you cover it with glaze, then your creative object can be used in everyday life.

Nowadays the practice of firing clay at home is very popular. There is nothing complicated here, except that you should adhere to safety precautions and have the necessary space and sufficient power for firing.

To begin with, the product must be left in a dark place (or without direct exposure to sunlight) to dry. Changes and drafts will adversely affect the quality of clay firing - this is worth taking into account. The thinner the walls of the product, the faster it dries and the less time it takes to get rid of unnecessary moisture, and vice versa. This also applies to the firing time; the larger and thicker the object, the longer it takes to bake; the range varies from 4 to 12 hours. On average, this happens to be about 6 hours, but this is all individual.

When laying out your works, you should follow their arrangement according to the “pyramid” pattern: the largest objects should be located at the bottom, then higher up with a gradual decrease. Weight is of no small importance: the heaviest products should be at the bottom. At this stage, you don’t have to be afraid that they may stick to each other - feel free to lay them on top of each other. Close the oven.

The maximum clay firing temperature reaches 900 degrees. But warming up should occur with a gradual increase. If you have a professional oven with temperature control, then the first heating should be set to 150-200 degrees. This temperature will remain for no more than 2 hours. Then we add another 200 degrees and keep the clay objects in the oven for the remaining 2 hours. And we repeat this until we reach a value of 900 degrees, and hold it for some more time.

How to fire clay

As a rule, clay is fired at home in a homemade oven. In this case, the temperature regime must be monitored on an ongoing basis. It will look like this:

1. We start from the first position of the switch, hold it for 5 minutes and turn it off.
2. After 5 minutes, turn it on, leave the clay to bake for 10 minutes and turn it off.
3. After 15 minutes, turn it on, wait again for 10 minutes and turn it off.
4. At this stage, turn on the oven and let the clay burn until the products turn red.
5. Here we turn the switch to the second position and follow the same pattern: 5-5 minutes, 10-10 minutes, 15-10 minutes. Moreover, here you do not need to turn off the stove, but only go down from position 2 to 1 and back.
6. Position 3 is applicable if the oven power is not enough.

On average, the entire clay firing process takes up to 6 hours. You can determine “readiness” by the glow of the walls inside the oven. As soon as the glow turns light yellow, turn off the oven.

Do not immediately open the door; leave the products to cool in the oven for a long time, for example, overnight. This will allow it to cool evenly after firing. Then you can cover them with glaze and let them dry, so your creation will last you much longer.

Clay crafting

If you want to use clay without firing, then you need to choose it with polymer additives.

Before you start sculpting, you need to knead the polymer clay thoroughly with your hands and tap it with your palms. These manipulations will release excess air from the material. This is necessary if you still decide to fire (but not necessarily). It is more convenient to shape the product by working with both hands, starting with larger objects and ending with the smallest ones. A stack will come to your aid; it is a sculpting tool. When the work is completed, wipe the product with a damp sponge or brush.

How to sculpt correctly

Clay, although a plastic material, is more durable than plasticine. Therefore, there are several important recommendations for handling it during sculpting:

• The clay should always be moist, do not let it dry out.
• If cracks appear, immediately smooth them out with water or a water-clay mixture.
• Modeling work begins with large objects, smoothly moving to smaller ones.
• You should not roll foreign objects into the clay; it is better to make separate recesses in the product for this purpose.

When everything is done, you need to leave your figurine to dry for a couple of days. Although it looks great without firing, you can additionally bake it in the oven or microwave, but this is at your discretion. At the final stage, PVA glue can serve as a glaze for the product.

Polymer clay as a source of inspiration

When using polymer clay, firing is not a necessary process, but it creates a stunning effect of realism of the object. It looks very impressive.

Firing polymer clay can be carried out in an oven with a thermostat or on a homemade stove. But the most convenient way is the air fryer. When creating flowers, an air fryer is not suitable, as they will become thin. They require a temperature in the range from 110 to 130 degrees.

This means that none of the proposed methods work. Therefore, it is better to fire clay for flowers in glass containers.

Baking flowers from polymer clay

We place flower buds on toothpicks that are stuck into any soft object, for example, foil. Place all this in a glass container with a lid and place it in a well-heated oven. On average, it will take about 2-2.5 minutes for the product to be ready. But pay attention that their color does not change and the petals do not become thin. If this happens, then you have overexposed the product. You will be able to establish the exact firing time experimentally, depending on the operating mode of your oven and the volume of the product.

When firing polymer clay in the oven, it is important to take into account the temperature of the glassware - it should not be cold, it can be heated directly in the oven while it is heating.

Lactic clay firing(milking) is an ancient method by which pottery was made waterproof. After this firing, the product acquires a beautiful brown color of various shades. For milking, a product is taken that has undergone the first (final) firing at a temperature of 800 to 950 degrees. The product is dipped in milk, kept in it for some time and carefully removed, trying not to spoil the delicate milk film. After the ceramic has dried, it is fired again at a temperature of 300 to 350 degrees. The product is kept at this temperature until the desired color is achieved. However, to accurately guess the color with milk firing clay impossible, since it depends on the fat content of the milk, the firing temperature, and keeping the product at this temperature.

I sometimes got beautiful transitions of shades of brown due to the fact that under the oven, on which the products stood, was somewhat colder than the rest of the oven space. In addition to the beautiful color, the product becomes waterproof after milk firing. This is achieved due to the fact that milk casein coagulates at the firing temperature and clogs the pores of the ceramic.

Almost everyone who writes about dairy firing clay It is recommended to use exclusively village fat milk. This is correct advice, but all children's works presented in the photographs were fired using store-bought bottled milk with a fat content of 3.5-3.7 percent. It is necessary to avoid contact with the product of heavy cream, which leaves unsightly stains after firing. My initial attempt to avoid additional costs was unsuccessful: at the school where I work, I They provided some powdered milk, but nothing good came of it. So you need to use natural milk.

Dishes that have undergone milk firing are washed with a soft sponge without the use of abrasives. It should not be left dirty for a long time, so as not to breed mold. In the latter case, it can only be removed by repeated firing.

Since guests of my site are often interested in how to do clay firing at home, I tried to do milk roasting in the oven of a gas stove.

For the experiment, I took already fired small beads that I found at home.

I bathed them in store-bought milk.

And, strung on a wire, she hung it from the grate of the gas stove. I turned on the gas to the maximum setting. I don’t have a graduated thermometer in my oven, but I know to what division the needle can turn as much as possible. This time I was unlucky: it’s cold in the house, the heating hasn’t been turned on yet, people are heating themselves with gas and its (gas) pressure drops. So the oven reached its maximum temperature instead of the usual half an hour for two hours, no less.