So reproduction actually follows from the presence of dishes after the BP. Cups, bowls, jugs for drinks, all this will be missed in any case, no matter how We prepare. We often come across clay, and it’s not so difficult to sculpt from it, but it’s quite difficult to burn it.
Option one
Before firing, clay products must be dried at room temperature for 3-5 days, depending on the size. This evaporates most of the moisture in the clay. If the product is dry on the outside, and moisture remains inside, it may explode during firing. It also explodes when stones are present in the modeling clay. After firing, clay acquires new qualities - strength, rigidity, durability.
At home, when there is no muffle furnace, products can be fired on a conventional electric or gas stove.
In this lesson, we will use an electric stove.
Using for firing their clay products - a small frying pan and a cast-iron pot. At the bottom of the pan, pour fine sand for gradual heating. We put the figurine on the sand and cover it with a pot.
The heating temperature must be increased gradually. First, I turn on the minimum heating for 30 minutes, then we increase the temperature to a maximum for 5-6 hours. Before removing the clay figurine, you must wait for it to cool completely.
Second option
I happened to use the most primitive and unpredictable method at the dacha - firing at the stake (in the special literature this is not recommended, since this wild method can ruin your work). I decided to conduct an experiment. I folded a small double-sided masonry of bricks (it is better if it is possible to lay it out on four sides and leave room for a closed hole to make it easier to kindle a fire). The height of my masonry was 4 bricks, but this is not so important, the main thing is that later it would be possible to cover this masonry from above along with the product and leave it until the fire completely fades and cools down. And you need to put the product so that the coals do not come into contact with it. To protect products from contamination and mechanical damage during firing in an open fire (on a fire and in a furnace), they can be placed in special capsules. The simplest capsules are made from cans, punching several small holes in them so that the products do not darken during firing.
First, light a fire (only birch logs are suitable), then make a central place for the dried one (this is required condition for any firing!) of the product, and place it on a brick base or in a capsule on the ground so that there is a high temperature on all sides when the fire flares up (this is necessary for uniform firing). A more or less gradual increase in temperature will be required. I heated the product in an electric oven and, in a warm mitten, transferred it to a heated place by the fire (to avoid temperature differences). If you put it cold, then do not let the fire close at the beginning of firing, let it warm up, then observe the temperature. When we cook kebabs, we protect the meat from fire, and clay can not be protected, just let it gradually get close to it so that the product does not break from a sharp increase in temperature, and when the fire stops rising, you can cover it with something fireproof from above (with a lid from a brazier, a piece of an old metal sheet, etc.). I had a rusty roofing piece at hand, with which we blow the fire to kindle. Then you can leave it uncontrollably to burn out and cool. The whole burning process is at least three hours, and it will take a slow time to cool down, so in the evening, and running, nothing will work (you need to watch the firing). The product must be heated from all sides, otherwise you will hear clicks from breaks (it is better not to plant children nearby, suddenly a fragment will fly off), such a practice is possible with this method. Successful results are obtained with small products, whistles, but you still do not have a guarantee to save each of them.
Clay products are a very exciting and interesting process that allows you to reveal your imagination and talent. If you want your clay figures not to lose their shape for a long time, they need to be dried, and then the clay is fired at home, adhering to a certain technology. After all, the long service life of your products will delight you all the time. All your figurines are unique - they only look like themselves.
Material composition
Clay can have a different composition. It directly affects the firing technology. The composition of natural clay includes an admixture of sand. There is such a regularity that the less sand is included in the composition of the clay, the lower the temperature should be when firing products. There are situations when, when using purchased powdered clay, it boils at 750 degrees and then dries up. As a result, the product resembles a porous sponge. In this case, the clay figurine is usually destroyed.
The composition of the clay must be free of air and stones. Never use inhomogeneous materials because an explosion may occur. Since the composition will include materials that have different densities, and they will expand each in their own way, with a change in temperature. 
Natural clay is a material of natural origin and often does not undergo additional processing. In nature, you can find clay of various colors, which depends on the presence or absence of certain elements. For example, clay acquires a red color due to the presence of a large amount of iron. And if there are small amounts of iron and titanium oxides in raw clay, then the white color of the material remains even after firing.
Preparing material for firing
Before firing clay, it must be dried. You will spend about a week on this process, depending on the size of the product. It is recommended to dry it in those places where there are no heating devices nearby, and where direct rays of the sun do not fall. The best option is room temperature and a dark, dry place. It is there that the product will dry evenly.
If the clay has dried unevenly, then cracks or chips may form on the product. If it is not dried enough, then the products may have defects after firing. But it is impossible to dry out the clay.
When the product dries, it must be carefully examined for cracks. If they are present, they can be masked with liquid clay, but this does not guarantee that the product will not lose its shape during firing. It is best to prevent cracks from appearing. This can be achieved, it is enough just to properly prepare the clay and mold the product with high quality.
The final stage of preparation is the grinding of the clay figurine. During grinding, fingerprints and bumps are removed, as a result, the products acquire a beautiful and well-groomed appearance. Grinding is carried out with sandpaper.
Another important factor is the quality of the molding. Make sure that there are no air bubbles in the figure during sculpting. When the temperature rises, the air expands and seeks an outlet, as a result of which the product will break. When you fill up cracks or hold together particles, do it very carefully so that air capsules cannot form.
Rules for firing at home
You can burn clay at home. First you need to dry the product, and then burn it in the oven. In this case, it is necessary to smoothly increase the temperature within two hours to 200 degrees. Clay figurines can be placed in a frying pan or cast iron pot. It should be noted that it is impossible to do a full-fledged roasting in the oven, because insufficient temperature, it cannot harden it, but only dry it.
How can you tell if a product is ready?
Very easy, based on color, weight and sound. If the color of the fired clay is black, then the figurine is overheated. If the color has not changed, it means that the product was not burnt enough. Fired colored clay should be red.
Clay firing technology
Clay kiln
The best option for firing clay - it is a muffle furnace . This oven has adjustable temperature. It should be remembered that such a furnace is very expensive and not everyone can afford to buy it. But there is no need to be upset, because it can be replaced with other good appliances, for example, firing clay in the oven. Start firing the clay at 200° for 2 hours. Then, within 6 hours, gradually raise the temperature to 1000 °. Such temperature regime allows you to protect the clay product from stains and help maintain a uniform structure.
Clay firing can also be done in barbecue or brick oven . These species are a closed space, which is characterized by a stable temperature. It is needed so that the clay product heats up evenly, and various defects do not form on it, such as surface spreading. The product to be fired must be left until the fuel burns out completely and the firebox cools down. The product should be in the oven for about 4 hours.
Firing a pottery over a fire is a very affordable option. It is used for firing small items. So, take a pottery and place it in a tin vessel, which you have previously heated and made holes on the sides. In most cases, the vessel is an ordinary tin can. Burn the product for about 8 hours, no less.
fire the clay not possible in the microwave. . Such an oven can only remove moisture. Clay products, after you have dried them in the air, are placed in a microwave unit for 3 minutes. This is done to improve their condition.
Temperature regime
The main rule in firing clay products is that you need to gradually raise the firing temperature, and then gradually lower it, giving time to cool the product. At first (the first 2 hours) the temperature should be no more than 400 °. The firing temperature may fluctuate in the range of 200-1000° during firing. If the temperature is lower, then the firing will be insufficient, and the figurine will not have the desired properties. If the temperature is very high, then the figurine may collapse.
Duration
This process can take from eight hours to several days. It depends on the size of the product and the firing technology. If the figure is small, then this can be done as soon as possible.
It's important to know!
- Once the clay has been fired, it is no longer possible to change the product.
- You can do firing more than once, while gradually raising the temperature in order to achieve the optimal result and gain experience.
- When you have completed the main firing, you can apply a special coating to the figurine and then fire it again. This coating will melt and the resulting glaze will form.
- During drying and firing, the figurines can be deformed and decrease in size. That is why when creating a product, the composition of the clay and its future purpose should be taken into account.
- If the clay contains a lot of sand, then the product will be less compressed.
- Also remember that organic compounds burn out during firing, which in turn leads to unpleasant odors. Therefore, it is required that the room be ventilated.
To give clay products additional properties, they are subjected to high temperatures - firing. But the clay firing technology 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. Dry the product away from heating appliances, direct sun rays, 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, the product will dry evenly.
With uneven drying, the product may crack and its small parts will simply fall off. Insufficient drying will result in firing defects. It is impossible to dry 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 the appearance of cracks, and this is obtained with high-quality modeling and competent preparation of clay.
Be sure to check the sound of the whistle - if it disappears or becomes deaf, then it's not too late to try to fix it.
In some situations, during the drying time, a spider can settle in the products (there was a case when he chose one of my whistles), in which case he needs to be moved to a safe place .
final stage preparation will be grinding products. When grinding, fingerprints, various crumbs and bumps may disappear, and the product will acquire a noble appearance. Grinding can be done with sandpaper of small numbers.
Conditions for firing
Temperature. The most important thing in firing is a gradual increase in 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 products can be fired in a short time.
The composition of the material. The firing technology largely depends on the composition of the clay. Natural clay has an admixture of sand and the less sand, the lower the firing temperature. In my practice, there were cases when purchased powdered clay at 750 degrees literally boiled and dried out in the form of a porous sponge. The product was completely destroyed. The composition of the clay should not contain stones and air. If the material is not homogeneous, a break will occur. Since materials of different densities will expand with temperature changes in different ways.
Modeling quality. The main requirement for modeling is the absence of air bubbles in the product. When the temperature rises, the air will expand and will seek an outlet, tearing the product. Therefore, when filling cracks and fastening parts of the product, exclude the possibility of the formation of air capsules.
Firing methods
Firing in a muffle furnace. There are several ways to fire clay products, but the most common is firing in a muffle furnace. This is an electric oven equipped with a temperature control mechanism.
Modern furnaces have automatic firing programs for products of various types, a window for viewing the status of products and other options. Another important characteristic of the muffle furnace is the volume of the chamber. Some swords have a cylindrical chamber in which only small items can be placed, and there are large kilns for firing pottery and sculptures.
Firing at the stake or in a non-electric oven. A rather non-trivial task, primarily due to the fact that there is no way to fully control the temperature. In addition, the stove is rarely heated for eight hours, and it is difficult to sit around the fire for a third of the day. However, if you are still going to - place the product in a container with sand - this will smooth out a sharp rise in temperature.
Roasting at home. A clay product can also be fired on a gas or electric stove, but I warn you - this is quite dangerous and the firing quality will still be far from ideal. To do this, you can take a cast-iron pan with washed dry river sand and put it on fire. From above, you need to carefully install the product and cover it with a fireproof container - a clay pot or pan. The process must be monitored and the room should be regularly ventilated so as not to cause overheating and oversaturation of the air with toxic gases.
Why roasting is needed
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 turned into a single ceramic ingot, which is resistant to deformation and moisture penetration. Hence the need for roasting.
Fired products are ready for painting, and after painting they are ready for use.
It's important to know
After firing, the clay is not suitable for modeling, as it is no longer clay, but ceramics.
Firing can be done from several times, gradually increasing the temperature limit to achieve optimal results and gain experience.
After the main firing, the product can be coated with a special composition and fired again. When melted, the composition forms a glaze.
During the drying and firing process, the product can be deformed and eventually become smaller than planned. Therefore, when creating a product, it is necessary 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 turned black - the product overheated, if it did not change color - it was not burned enough. Fired products have a lighter weight and a sonorous nature. However, whistles during firing can completely lose their sound (irreparably) or, on the contrary, change.
In any case, proper firing of pottery can only be achieved with experience. So keep it up and good luck!