How to burn clay yourself. Clay firing: technology, rules, temperature conditions and types. Clay crafting

What is it needed for clay firing? Yes, so that your product or craft is stronger and serves longer and pleases you. After firing, if possible, the product can be decorated with glaze, or you can simply paint with acrylic paints.
Roasting is a very complex process. Roasting is not baking pies in the oven. It is much more difficult and cannot be done in an hour or two. Yes, and ordinary kitchen ovens, and even more so microwave ovens (as many people think) are not designed for this. For firing, special muffle furnaces are used. In them, the temperature rises to 950-1200 degrees.
But before firing the product, it must be dried. That is, just fashioned can not be immediately put in the oven and fired. It must be left to dry for several days. All moisture should evaporate from it. Dry the product away from drafts, and not in the sun. Otherwise, it will dry unevenly and cracks may appear on it. Also, the product, with uneven drying, can “lead” and, if, for example, it is a whistle, then after drying it may stop whistling well.
In general, there are many different nuances in working with ceramics. You can't describe them all at once. Their knowledge gradually accumulates with experience.
Yes, and clay is a kind of material. Clay great variety. They differ from each other not only in color, but also in plasticity, melting point, shrinkage and many others. Speaking of shrinkage. Shrinkage is when an item decreases in size during drying and firing.
The product is placed in the oven already dried. During firing, the temperature in the kiln is raised gradually. On some they stop. All this is due to the fact that the product goes through several stages during firing, and at the same time complex processes take place inside it at high temperatures.
At the first stage, up to 300 degrees, the clay product loses physically binding water, and the temperature at this stage is increased slowly. Let the remaining water evaporate. Otherwise, the product may break. Then, at temperatures up to 600 degrees, recrystallization begins. And here it is necessary to linger for 40-60 minutes. At the final stage, up to 850 degrees, you also need to linger. At these temperatures, sintering occurs. Only after sintering, the clay product will become strong, it will acquire the correct ceramic color. In a word, during firing, everything happens smoothly and slowly. It takes me almost 7 hours to do this.
But even after firing, one should not rush, and the furnace is not immediately opened, but allowed to cool down to about 200 degrees. Otherwise, with a sharp change in temperature, cracks will appear on the products.
And here is the final stage - opening the furnace. This long-awaited exciting moment brings great joy and other indescribable feelings. And having experienced it for the first time, it is clear that everything that was previous was not in vain. And modeling with a painful creative process, and slow drying and troublesome waiting during firing - all for good reason. And there will be a desire to pick up the clay again and again go all this way from a shapeless cool piece to the finished product.

From which our ancestors made a lot of useful household items. Later, jewelry for women began to be made from this material. Her color scheme can be very diverse: red, brown, gray, white, blue, yellow and combinations. It depends on its mineral composition. Now, in order to get clay, it is not necessary to go in search of 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 may be suitable for its creative embodiment in an object of art or everyday life.

How can clay be useful?

Any activity that consists in the combined interaction of manual labor and fantasy not only captivates the mind of the master, but also helps the young body to develop fine motor skills of the fingers. And this means that thinking, imagination, color sense, object geometry and much more - will give the child the opportunity to develop their 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 a pure heart will not leave anyone indifferent.

Clay firing at home

If you want to give your handicraft a long life, then firing is a must. So that during this process the product does not lose its shape and does not crack, it is very important to follow the clay firing technology in accordance with its standards. Due to the impact on the clay of high temperature, the product acquires strength, it "stones". And if, after all the required manipulations, glaze is applied, then your object of creativity can be used in everyday life.

Now 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, sufficient power for firing.

It’s worth starting with the fact that the product must be left in a dark place (or without direct exposure to sunlight) to dry. Drops and drafts will adversely affect the quality of firing clay - this is worth considering. The thinner the wall thickness 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 more time it takes to bake, the range varies from 4 to 12 hours. On average, it happens about 6 hours, but it's all individual.

When laying your work, you should observe their arrangement according to the “pyramid” scheme: objects should be located at the bottom of the largest size, then higher with a gradual decrease. Weight is also important: the heaviest products should be at the bottom. At this stage, you can not be afraid that they can stick together to each other - feel free to lay them on top of each other. We close the oven.

The firing temperature of clay at its maximum reaches 900 degrees. But warming up should go 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 be kept 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 so we repeat until we reach a value of 900 degrees, and hold on for some more time.

How to fire clay

As a rule, clay is fired at home in a homemade kiln. 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 for 5 minutes and turn it off.
2. After 5 minutes, turn on, leave the clay to bake for 10 minutes and turn it off.
3. After 15 minutes, turn on, hold again for 10 minutes and turn off.
4. At this stage, we turn on the furnace, and withstand the firing of the clay until the products turn red.
5. Here we turn on the switch to the second position and in the same way: 5-5 minutes, 10-10 minutes, 15-10 minutes we stand. And 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 furnace power is not enough.

On average, up to 6 hours is spent on the entire process of firing clay. You can determine "readiness" by the glow of the walls inside the furnace. As soon as the glow becomes 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, all night. This will allow it to cool evenly after firing. Then you can cover them with glaze and let dry, so your creation will last you much longer.

Clay crafting

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

Before starting sculpting, polymer clay must be thoroughly kneaded with hands, tapped with palms. From these manipulations, excess air will come out of 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 two hands, starting with larger objects and ending with the smallest ones. A stack will come to help you, this is a sculpting tool. When the work is completed, wipe the product with a damp sponge or brush.

How to sculpt

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

• Clay should always be wet, do not let it dry out.
• If cracks appear, immediately smooth them with water or a water-clay mass.
• Work on modeling begins with large objects, smoothly moving on to smaller ones.
• It is not worth rolling foreign products into the clay; it is better to make separate recesses in the product for this.

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 up to you. PVA glue at the final stage 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 the realism of the subject. Looks very impressive.

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

And this means that none of the proposed methods does not work. Therefore, firing clay for flowers is best done in glassware.

We bake flowers from polymer clay

We place flower buds on toothpicks that are stuck in any soft object, for example, in foil. We put it all in a glass dish with a lid, and send it to a well-heated oven. On average, about 2-2.5 minutes will be required 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 overexposed the product. You will be able to set the exact holding time for firing 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 during heating.

You can burn small ceramic products at home on a gas stove. The electric stove is not suitable for this, the electric burner does not give the required temperature.
For firing, it is necessary to make an elementary device from two cans. Cans should be tin, not aluminum. Their size should be chosen in such a way that the gap between the walls of the cans nested in each other is 1-1.5 cm.

The space between the walls is best filled with asbestos or mineral wool, in extreme cases, dry clay. Cover the edges with damp clay so that the heat insulator does not spill out.
Put the unfired product on the burner of the stove and cover it with the resulting heat-insulating cap. The head of my smoking pipe was burned in 2-3 hours. During the first firing, it is desirable to ventilate the room well, as the varnish on cans burns.

I made the working chamber from a small can (D = 6.2 cm; height: 7 cm; volume: 210 ml - a very popular packaging format for green peas or beans). A good lid came out of a piece of brick, which was carefully rubbed against the jar from the flat side and chopped off the excess from the sides and top. From another tin can (8.5 x 5 cm) I built a tripod in order to place the bottom of the firing chamber exactly at the top of the burner flame. The thermal insulation of the chamber walls was made of mineral wool impregnated with slip. As it turned out, such a material is easily molded and perfectly adheres to annealed tin in its raw form, does not crack at all when dried (even despite the fact that I stuck around the outside of the can) and firmly adheres to the surface, does not shaggy and does not prick the hands, does not sprinkle. It turned out such a strong "fur coat" thicker at the top. The bottom of the mineral wool-clay cocoon, after it had dried, was puttied with "putty" from the sediment remaining after elutriation of the clay mixed with an equal amount of powder from crushed red brick. From the same material I formed six ribs, by which the entire camera was held on a tripod. He polished the dried "putty". The very bottom of the can-chamber (2-3 mm) and the bottom left open - these parts must be completely in the flame.

The process went like this:
He placed the installation with an open lid above the burner (the products for firing were already inside the chamber); lit the smallest fire and it burned like that for five to ten minutes; the next fifteen minutes gradually opened the gas to a third of the power; during this time, drying of the products took place. Then he closed the chamber with a lid and within 20 - 30 minutes opened the gas to the maximum, while controlling the uniformity of the chamber glow according to the color of the bottom heat. Further roasting spent as much time as he could afford - three hours. The gas was gradually shut off over the course of about half an hour.

However, still a good shard was obtained if the procedure was repeated twice. Those. in a good way, the firing time needs to be increased to 5-6 hours, I will definitely try it when I go on vacation.

Another option

FINALLY I burned it. Ceramic pipe for smoking. Just did it like this. I drove up to the construction market and bought 10 pieces of fireclay refractory bricks (SHA or ShB). On the grate of the slab, I carefully laid out the square in such a way that it was covered with two bricks from above. About 6-8 is needed. Then he put the product there, turned it on to a minimum and raised the flame every 20 minutes. Firing patience was enough to spend 3 hours. As it turned out, more than enough. At the same time, the product was in red hot form.
After cooling, the product acquired a characteristic ceramic ringing, strength and is not washed away by water.
Thanks to the author for the post. We write practices here.
I plan to assemble a muffle chamber furnace on my own.

Lactic clay firing(milking) is an ancient method by which a pottery was made waterproof. After such firing, the product acquires a beautiful brown color of various shades. For threshing, a product is taken that has passed the first (ultimate) firing at a temperature of 800 to 950 degrees. The product is dipped into milk, kept in it for some time and carefully removed, trying not to spoil the delicate milk film. After the ceramic dries, it is fired again at a temperature of 300 to 350 degrees. At this temperature, the product is kept until the desired color is achieved. Still accurately guess the color when milky clay firing impossible, since it depends on the fat content of milk, the firing temperature, and holding 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, it was somewhat colder than the rest of the oven space. In addition to the beautiful color, the product acquires water resistance after milk firing. This is achieved due to the fact that milk casein coagulates at the firing temperature and clogs the pores of ceramics.

Almost everyone who writes about dairy clay firing It is recommended to use only country fat milk. This is correct advice, but all the children's works shown in the photographs were fired using shop bottled milk with a fat content of 3.5-3.7 percent. It is necessary to avoid getting fatty cream on the product, which leave ugly spots after firing. My initial attempt to do without additional costs failed: at the school where I work, I some dry milk was provided, but nothing good came of it. So milk should be natural.

Milk-fired dishes are washed with a soft sponge without the use of abrasive products. It can not be left dirty for a long time, so as not to dilute the mold. In the latter case, it can be removed only by repeated firing.

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

For the experiment, I took already burnt medium-sized beads that were found at home.

I bathed them in store-bought milk.

And, strung on a wire, hung it to the grate of a gas stove. Gas turned on to the maximum value. I don’t have a graduated thermometer in my oven, but I know to what division the arrow can turn as much as possible. This time I was not lucky: the house is cold, the heating has not yet been turned on, the people are heated by gas and its (gas) pressure drops. So the oven reached its maximum temperature instead of the usual half an hour, two hours, no less.

1. Where do you get clay?
- Clay for modeling can be bought at stores that sell art supplies. Clay is also sold on the Internet, you can use the services of a search engine to find such stores. As for the Moscow region, there is clay in Gzhel and it is cheaper there. In Moscow, for example, a shop for ceramists Hors on Ul. Upper Maslovka, 18 or Vorontsovsky Combine, Ul. Architect Vlasov, 57

2. Is it possible to dig up and use clay from a quarry for modeling?
- It is possible, but for 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 are well suited). Then the clay is poured onto gypsum slabs (you can make them yourself or buy them in specialized stores, in the same Horse) and it is “pulled off” - the gypsum absorbs excess moisture, and the dried clay is easily removed from the slabs and can be used for modeling. If without 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 a state where you can sculpt from it. With gypsum boards, clay dries much faster.

3. Can clay be fired in an oven or microwave? Or do you need a special oven?
- It is impossible, because the temperature of the order of 1000 degrees is necessary for roasting. The oven only warms up to 250. A microwave will not work either, you need a special oven.

4. Can I put a kiln at home?
- Can be small. It can be either a muffle laboratory furnace made at the factory. Or assembled by a stove-maker according to your individual sizes. Potters usually know good stove-makers and can be advised by craftsmen. But it should also be borne in mind that it is not useful to breathe the fumes that are released during firing, and it is still better to use a separate room for the furnace, preferably with an exhaust hood.

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

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

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

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

9. What should I do if my cat's ears fall off after drying?
Depends on what kind of clay you made it from. Some clays allow you to slightly soak the place where you need to glue the ears and the ears themselves and try to smear them. If this number does not work with your clay, you can burn it and, after firing, glue it either on glaze or on silicate glue, if you do not plan to fire with glaze. And in the future, even when sculpting, try to stick the parts well on water or on a slip - this is the name of liquid clay.

10. Can a crack in a ceramic product be repaired?
Depends on the crack. If this is a micro crack, then it is likely that it will hide under a layer of glaze, but it can, 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 with acrylic paints, you can repair the crack with plaster and then paint with acrylic. Gypsum can be used to seal cracks of any size. Products coated with acrylic paints cannot be used for food purposes.

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