Brick stoves, despite several centuries of use and the development of new technologies, have not lost their popularity today, especially in rural areas. A brick stove is a complex heating structure, the internal volume of which consists of several zones exposed to high temperatures of different ranges. But even in the least heated compartments, the strength and tightness of the stove body and chimney are very important, since the leakage of combustion products into the premises threatens the lives of residents with poisoning or fire.

Material of manufacture stone ovens There are two types of bricks - heat-resistant and regular red, laid on a solution of a certain composition (depending on the heater zone). A Russian, Dutch or Swedish stove is a massive structure, and the consumption of materials for its construction is significant. At the same time, the cost of purchasing bricks cannot be avoided, but you can save on masonry mortar - do not buy ready-made heat-resistant mixtures, tempted by the deceptive cheapness, but prepare them yourself.

Ready-made dry masonry compositions for furnaces and natural clay

The strength and uniformity of the brick is controlled by the manufacturer during manufacturing, so they are rarely questioned. But the quality of homemade mortar, the second most important material when constructing a furnace, depends on the characteristics of the components and the correct manufacturing.

Let's take a closer look at stove masonry mortars and what kind of clay should be used for laying stoves.

Types of clay solutions for stoves and fireplaces

When laying a furnace, depending on the temperature conditions of the area being built, several types of mortar are used:

• 1200-1300 0 C - clay-chamotte and cement-chamotte;
• 1100 0 C - clay-sand mixture;
• 450-500 0 C - lime-sand;
• 220-250 0 C - cement-lime;
• range of atmospheric temperatures (kiln foundation) - cement-sand mixture.

Of the listed masonry mortars, clay or fireclay made from it are included in three mixtures: clay-sand, clay-chamotte and cement-chamotte).

Let's look at these important components oven mixtures for masonry.

Clay components of solutions for brick heaters

Clay is a sedimentary rock with a fine-grained structure, the forming substance of which is kaolinite, consisting of a mixture of silicon oxides (47%), aluminum (39%) with water (14%). The name kaolin comes from the Chinese locality Kaolin, where such clay was first discovered white. If kaolin clay contains iron ions of different valencies, the color of this material may be different - yellow, red, brown, blue, green, but physical properties this has little impact. In a dry state, clay is a lumpy material made up of fractions various sizes, when mixed with water, forms a plastic mass with good adhesion.

Clay quarry and clay sample of plastic consistency

Chamotte is a powder obtained by grinding pieces of clay that have been sintered during high-temperature firing and have lost molecularly bound water. The size of the fireclay crumb fractions after crushing or grinding ranges from 0.2 to 2.5 mm. Sifting fireclay powder allows you to separate fractions by size, after which finely ground powder is often called fireclay clay, and coarse powder is often called fireclay sand, but chemical composition and the properties of these materials are identical - high heat resistance and low water absorption.
Fireclay filler for industrial production and packaging

The degree of clay sintering depends on the magnitude (or) and duration of high-temperature exposure, which determines the division of fireclay into:

• low-burnt - firing temperature 600-900 0 C, water absorption up to 25%;
• high-burnt - for regular firing at 1300 0 C and water absorption of less than 5%, for special quality - at 1500 0 C with water absorption of less than 2%.

Important! The shrinkage of solutions using low-burnt fireclay is up to 16%. However, the porosity of such solutions after curing is much lower than that of mixtures with high-burnt filler, since the difference in the shrinkage of low-burnt fireclay and the binder (clay) is very small. Therefore, to obtain heat-resistant bricks with low porosity, high compressive and fracture strength, low-burnt fireclay is used, and for masonry mortars, high-burnt fireclay is used.

Characteristics of clay for oven mixtures

The main characterizing parameter of this material is fat content, which combines the degree of plasticity, strength, water resistance, as well as adhesion before and after curing.

In nature, clay comes in three types - lean, medium fat and oily, with no clear boundaries between them.

The belonging of a material to one of the types is determined by simple mechanical manipulations, the most accurate of which is performed as follows.

Approximately half a kilogram of clay is mixed with water to a homogeneous dough-like consistency, after which a ball with a diameter of approximately 5 cm is formed from the resulting mass.

The ball is placed between two pieces of glass, which are used to slowly squeeze it, observing the formation of cracks in the clay:

• the destruction of the ball at the beginning of squeezing indicates low fat content - the clay is thin;
• the appearance of thin cracks after reducing the diameter of the sample by 1/3 of the original value indicates that the clay is of normal fat content;
• if cracks appeared only when the ball was squeezed to half its diameter, it is a mass of high fat content.

Determination of the fat content of clay by squeezing: on the left – fatty, on the right – normal.

The main factor influencing the fat content of clay is the percentage by weight of sand in it:

• from 15 to 30% - skinny;
• from 5 to 15% - medium fat content;
• up to 5% - fatty.

Production of clay masonry mortars

This or that type of clay oven mixture purchased in a store is prepared according to the instructions on the package; no questions arise here.

If the decision is made to use a homemade mortar for laying the stove, then there are two main conditions on which the quality of preparing the mixture depends - correct preparation of the components and compliance with the proportions of the components.

Using the example of a clay-sand mortar, we will consider preliminary operations and mixing rules.

Using the data in this table as a basis, you can achieve High Quality masonry mortar, slightly adjusting the proportions in relation to the parameters of the components used.

Natural clay prepared for the kiln must be cleaned of foreign impurities - everything foreign (plant remains, stones, debris) is manually removed, and large lumps are broken up. Then the mass is rubbed through metal mesh with a cell format of approximately 3 mm.

This “dry punching” is a labor-intensive procedure, so it is more rational to pre-soak manually cleaned clay for 2-3 days in a tin trough - lay it in layers of 12-15 cm, wetting them abundantly, then cover the entire packing with water (approximate ratio: 1 part water per 4 parts clay). After 2 days, mix thoroughly with feet or a stirrer and rub through a sieve with a mesh size of 2-2.5 mm.

Ways to soak clay

During soaking, sand is prepared. Fireclay sand does not require preparation, except perhaps sifting if purchased in bulk. A river sand must be sifted through a sieve with a mesh size of 1-1.5 mm, then rinsed running water in a container until the turbidity disappears and place on a clean inclined plane to remove as much residual moisture as possible.

There is no strict ratio of the volumes of these components, since any clay initially contains some amount of sand. Therefore, the proportion can be from 1:2 to 1:5; ideally, the clay should only fill the voids in the solution between the grains of sand.

To have an approximate idea of ​​the volumetric ratio of the components, the bucket is filled 1/3 with a clay suspension when it is ready, and then sand is added along the edge. The materials are thoroughly mixed in any container to the desired consistency with the addition of the required amount of water. The readiness of the mixture for laying the stove is checked as follows - it must be held on the trowel after turning its plane by 180 0 and slide off it in a vertical position.

Testing the readiness of clay-sand mortar

If the mixture falls from a base turned 180 0, then clay must be added to it. If the solution does not slide off vertical plane- add sand. After correction, the check is repeated.

By testing the solution in this way, an approximate volume ratio of the components is obtained.

Clay-sand solution is used in furnace zones with temperatures up to 1000 0 C. Full or partial replacement river sand onto fireclay allows the mixture to be used for laying fireboxes with operating temperatures up to 1800 0 C, including in places of direct contact with flames.

Important! Clay mortars without the use of cement allow you to disassemble a brick heater after curing and reassemble it without destroying the elements.

Options classic style stone ovens

A more clear answer to the question of how to prepare a mortar for laying a stove is given in this video:

Conclusion

Availability of clay in natural conditions does not mean its primitiveness as a building material - solutions based on this mineral, prepared correctly, have served in stone heaters for centuries. Therefore, the use of clay-based mixtures is a sign of professionalism of the stove maker, and not a reason for skepticism.

The main point of the article

1. A stone oven is a complex engineering structure, the effective use of which depends, among other things, on the quality of the materials used for its construction.
2. Clay is an affordable natural material that has not lost its popularity today, and is superior to Portland cement in a number of characteristics.
3. For high-quality masonry It is necessary not only to choose the right clay for the stove being built, but also to prepare it well for adding it to the solution.
4. The high quality of the components of the mortar for laying the furnace guarantees the functionality of the mixture only if the required proportions are observed.
5. The advantage of clay, among others, is the ability to completely rebuild the masonry without damaging the dismantled materials.

Regardless of what type of mixture is used to lay the stove, it must be effective, because this is structural strength, good appearance, safety during operation. There are several main compositions: clay, cement, lime. Each type of mortar is used at different stages of construction, so it is impossible to determine a universal option.

Absolutely all experts agree that bricks should be laid on clay.

Only this material has the necessary characteristics:

1. When heated, the volumetric expansion of a normal mortar will coincide with that of a brick. This prevents the occurrence of cracks during operation.
2. The material does not emit harmful substances at high temperatures.
3. The strength when heated remains the same.
4. The necessary adhesion between the bricks is ensured.

To prepare the correct mixture, you need to follow a number of steps.

Deciding on proportions

Clay is divided into fatty and lean. The greasy solution will be plastic, but will crack after completely dry, the thin one will begin to crumble under the influence of a small force.

There are several methods for determining the required amount of sand in a solution:

Ball method

To begin with, equal amounts of clay are poured into 5 containers (a liter jar is fine), after removing large lumps. Then sand is poured into the jars in a ratio of 10, 25, 75, 100, 150%. Add water and solution and mix thoroughly until a homogeneous mass is obtained.

From each sample a ball with a diameter of 5 centimeters is molded, which we turn into a cake about 3 centimeters thick. Let the material dry for 10 days at a temperature of 20 degrees (room).

After this period, the edges of the cake are carefully examined. Cracks have appeared - the composition is greasy, crumbles when pressed - thin. A normal cake is not damaged and can withstand a fall from a height of one meter.

Paddle method

A container (usually a bucket) is filled with clay and sand. Gradually adding water and stirring, a creamy solution is achieved. Using a flat board, mix the contents a little and take it out. If a millimeter-thick mixture remains on the board, you need to add clay. Two millimeters and the presence of clots are the norm, but anything more is a greasy solution, you need to add sand.

Flagella method

From the composition with different proportions a roller is molded (15 millimeters thick and 15 centimeters long) and stretched. The fatty sample stretches easily and has a small thickness at the breaking point. A normal flagellum after rupture has a diameter of about 3 mm, but a skinny specimen breaks quickly and practically does not decrease in size at the ends.

Cleaning clay and sand

1. Sand. It must be sifted through a sieve with a mesh size of 1.5 by 1.5 millimeters. Having gotten rid of large particles, the sand is washed. For this purpose, a kind of net is made using ordinary burlap. The structure is fixed, material is poured into it and washed with running water until the water coming out of the net is relatively clean. Impurities have been removed.
2. Clay. There are 2 cleaning methods:
   
   • We pass the dry clay through a sieve with a mesh size of 3 mm (this is the thickness of the seam that is considered correct).
   • Alluvial method. Take an oblong container (small bathtub, or trough). Installed at an angle of about 8 degrees. Top part is filled with clay, the lower one is filled with water. In this case, the substances should not come into contact.

The clay is then washed or brushed with water using a scoop. Over time, a homogeneous mass forms in the lower part, which is transferred to another container and filtered.

Regardless of whether you purchased a ready-made composition or extracted the material yourself, the clay must be soaked before use.

To do this, pour it into a prepared container in a layer of 20 centimeters, level it and fill it with water so that the liquid completely covers the dry substance. Then the next layer is added and poured again.

After 24 hours, the composition is mixed, water is added if necessary, and only a day after this, the clay “sour cream” can be used for work.

Preparation of the solution

First, a sand layer is poured, then clay is poured, and sand is poured again. If there are clay puddles on top, sand needs to be added. The resulting composition is thoroughly mixed until a homogeneous mass resembling sour cream appears. To achieve greater strength, it is recommended to add 150–200 grams of salt per bucket of composition.

A high-quality mixture, when filtered through your fingers, gives a feeling of roughness, rather than a film with a small inclusion of grains of sand.

It will be easier to prepare a clay solution if you purchase the ingredients for it in a store. But you shouldn’t trust the manufacturer unlimitedly. It is better to check the fat content and sift the bulk materials.

Cement mixture

It is characterized by ease of preparation and great strength. But poor tolerance to high temperatures can lead to cracks in the masonry during stove operation. Therefore, it is most often used for building foundations or laying pipes.

Preparation:

Pre-cleaned sand and cement in the required ratio are poured into the working container. The proportions depend on the brand of cement, but the standard option is 1 to two (cement - one). In this case, the bottom layer is sand, the top is cement.

The solution is thoroughly mixed with the gradual addition of water. The resulting composition should be easily squeezed out of the seam between the bricks, but not leak out. Ready mixture It is recommended to use it completely within an hour after preparation.

Lime composition

When constructing stoves, more complex solutions using lime are also allowed. They are used mainly for plastering.

First of all, the lime is slaked with water and kept in a special container or pit for about 7 days. The result is “milk”.

There are several options for the mixture for preparing the solution:

1. Clay plus asbestos. Proportions: 1 part clay, one lime paste, 2 sand and 0.1 asbestos. First, a dry mixture is prepared, to which thick “milk” is added from clay and lime, mixed in a separate container. After this, the solution is thoroughly mixed.
2. Plaster with asbestos. Proportions: sand one, gypsum one, lime - 2 parts, asbestos 0.2. Preparation technology: dry ingredients are mixed without water and lime is poured in. After this, the finished composition is brought to a homogeneous mass and applied to the surface.

There is a limitation for such a solution - it must be used within 7 minutes. The culprit is gypsum, it hardens very quickly.

Tiling

To give a special shine, the stove is tiled. Clay mortar is not suitable for these purposes, as adhesion to ceramics suffers. Use cement mixture Also not recommended - the oven gets hot.

The best solution is a clay-cement composition. Proportions: clay and cement one part each, sand – 2 parts. Preparation: add clay diluted with water to the mixed sand-cement dry mixture and mix the entire composition thoroughly.

Preparing mortar for masonry and oven cladding is a very labor-intensive and responsible process that cannot be treated carelessly. It must be remembered that the structure will constantly be exposed to high temperatures, heat up and cool down. Therefore, a solution of poor quality will very quickly lead to the need to repair the stove, or even completely rebuild it.

A good result is guaranteed by:

1. Thorough cleaning of dry bulk materials from impurities and large lumps.
2. Precisely measured proportions of ingredients.
3. Qualitatively and slowly prepared clay and lime (if necessary).
4. Correctly selected type of solution. Nobody can prohibit using pure clay for foundations or cement for masonry, but the result can be very disappointing.

Remember! Violation of the tightness of the furnace core during operation can lead to carbon monoxide entering the living space, with all the ensuing disastrous consequences!

High-quality clay for laying stoves is one of the most important conditions for the reliability and durability of a future heating structure. Clay can be purchased at a specialized store or mined with your own hands. But in any case, it is necessary not only to be able to choose it correctly, but also to prepare it appropriately for

There are a considerable number of different types of clay, and not all of them are suitable for laying a stove. Therefore, it is worth understanding what this substance consists of, what qualities it must have in order to be used for construction work of such kind.

What is clay?

It would seem a funny question - each of us has known this natural resource since childhood. However, not everyone knows component composition clay and its specific properties used in construction practice.

Clay composition

The mineral components of clay can vary significantly in their percentage composition, but all its types necessarily contain substances from groups such as montmorillonites and kaolinites or other layered aluminosilicates. This kind natural material contains various impurities in the form of sand and carbonate particles, but its main composition is aluminum oxide - up to 39%, kaolinite - about 47% and water 14%.

In many ways, the composition of clay depends on the method and place of its formation. Thus, residual and sedimentary clays are released.

• Residual clays are formed during the weathering of non-plastic rocks and their transformation into plastic kaolins.
• Sedimentary clays are formed as a result of the transport of weathered natural products and their settling in a specific location. These can be clays formed on the ocean, sea or river bottom, as well as on the continental part. Marine rocks are divided, in turn, into coastal, lagoonal and shelf.

Clay is not a rare mineral substance, and is quite widespread throughout the planet. You can find it almost everywhere, so clay cannot be called an expensive material.

Basic properties of clay

Clay is a micro-grained substance, and regardless of where it is formed, it differs in its characteristics from other natural minerals. Due to its properties, it can be used not only in construction, but also in other areas of human activity.

• Clay quickly absorbs moisture and swells under its influence, while acquiring water resistance, that is, the ability not to let water through.
• Second, no less important positive quality The advantage of a mineral is its plasticity, thanks to which it can take any form.
• When dry, clay becomes highly durable. Due to this quality and water resistance, it is often used for arranging floors in basements or constructing “locks” around, for example, wells or the foundation of a house.
• In addition, very important qualities of this material are the high adhesion of the solution and its gas tightness.

Depending on the proportions of the ingredients in the clay, it may have different degrees of fat content. To be more precise, she can be skinny, normal fat and very fat.

Clay for stove masonry

Clay for stove masonry, already purified and crushed, can be purchased at a specialized store and used to prepare a solution. It should be taken into account that for laying just one hundred bricks, having a standard size of 250 × 120 × 65 mm and laid flat or on a “bed”, 20 liters of mortar will be needed, which is placed in two buckets.

The construction of the entire furnace, depending on its size and model, may require from 550 to 2500 bricks, not taking into account the masonry and foundation. Therefore, having calculated the costs of the required amount of all materials, it is quite possible to think about saving at least on clay and sand for mortar, especially since they can be found literally under your feet when you go out into the countryside.

If you decide to carry out this simple process of preparing such materials yourself, then some questions will certainly arise:

• Where can you dig up clay and find sand, thereby saving quite a significant amount?
• How can you determine the quality of a material and its suitability for oven mortar?
• How to correctly formulate a solution based on the fat content of the clay that was found?
• How to prepare the components for the solution?
• How to make the right batch?
• What components are needed for the solution, besides clay?

It is quite possible to find simple answers to these questions. And it’s worth starting in order.

How to find and select clay?

Clay is usually easy to find near any suburban area. The layers of this mineral do not lie too deep, but each of them can have different composition. Such layers can be clearly seen on steep banks of rivers or the sea, as well as in quarry developments. It is there that you can notice that numerous layers have different shades and densities.

It should be noted that even in one place, each of the layers, depending on the composition, may have different fat content, therefore, when selecting the desired material, it is recommended to take samples from several layers. It should be taken into account that the higher the layer lies to the surface, the fatter the clay. Therefore, it makes sense to immediately check the middle layers, since the mineral in them should have the most optimal fat content.

The lower layers usually contain thin clay, and if you dig it up, the solution will have to be “fattened” by adding very fatty clay to it. It is much easier to adjust a very fatty composition - it can be brought to normal condition by adding sand.

Solutions using clay of normal fat content have good plasticity, since it maintains a balance of its constituent substances. When the masonry dries, these mixtures practically do not crack and do not shrink. Well, and what is also very important is that they are much easier to work with.

Fatty solutions in their wet form are very plastic, and they are also convenient to work with, but when the moisture evaporates from them, they begin to crack and crumble into large fragments. Therefore, such clay will not impart reliability and durability to the masonry.

It is not recommended to use thin types of clay for oven mortars; they are not plastic and do not give strength to the masonry.

Video: An experienced stove maker shares the secrets of producing high-quality clay

Determination of clay fat content experimentally

If the clay is mined independently, its fat content can be determined immediately at the excavation site. To do this, you need to take a handful of the mineral in your hand, moisten it a little with water and knead it until smooth. Organoleptically, by touch, you can feel how high the fat content of the clay is. If it becomes sticky and plasticine like plasticine, then it is a fatty breed. Skinny clay, crumpled into a ball and moistened with water, will still crumble. This version of the material will have to be “fattened”.

There are several more accurate test tests for the fat content of this material, and they must be used to select the optimal clay option.

First way

You need to take about 0.5 kg of clay, which is diluted with 100÷130 ml. water. The mass is mixed until smooth. It is better to carry out this procedure manually in order, as they say, to tangibly feel the homogeneity of the composition, which at the end of kneading should not stick to your hands and have the consistency of plasticine.

From the resulting mass you need to roll two balls with a diameter of 40÷50 mm. One of them remains intact, the other is crushed into a cake. These test samples are left to dry for two to three days at room temperature.

If, after drying, cracks appear on the prepared parts, this indicates that the clay is very oily, and when mixing the solution you need to add a little more sand than indicated in the recipe.

If the cracks are insignificant, and the ball thrown onto the table from a height of 800-1000 mm does not break into pieces, then the clay has a normal fat content, this grade is excellent for masonry mortar.

Second way

To test clay using the second method, you will need 2÷2.5 kg of clay, which is kneaded using a paddle, adding water. You need to bring the mass to the consistency of plasticine, and if it still continues to stick to the wooden paddle, it means the clay is very oily. When mixing the solution, add more sand to it than required according to the recipe.

Clay, which has a normal fat content, remains on the funnel in separate clumps, but does not stick to it completely.

Third way

This method of testing clay for fat content is considered the most accurate. To carry out the test, take 0.5 kg of clay, which is mixed with water to form a thick dough. Next, a ball with a diameter of 40÷50 mm is rolled out of the resulting mass. Then, the ball is compressed between two smooth boards until cracks appear in the clay. In this case, the fat content is determined by the thickness of the cake and the type of cracks that appear.

• If the clay has low fat content or is thin, then even with slight compression the ball will crumble into pieces.
• If the clay is very oily, then when compressed by half the original diameter, narrow cracks form.
• If, when the ball is compressed by ⅓ of its original diameter, cracks appear in the clay, then it has normal fat content and is well suited for masonry work.

In this figure you can see ways to test clay for fat content:

1 — Determination of mineral plasticity:

a) lean clay with low plasticity;

b) normal clay has average plasticity;

c) fatty clay, high plasticity.

2 — Determination of plasticity using the “ball” method:

a) a ball of lean clay is compressed 1/5÷1/4 of its diameter;

b) a ball of clay of normal fat content shrinks to ½ of its original size.

3 — Determination of fat content using the “flagellum” method:

on the left is the tensile stretching method –

b) normal;

c) fat.

4 - On the right - method of bending around a rolling pin:

b) normal;

c) fat.

During testing, you can immediately adjust the resulting mass by adding fatty clay to the lean solution, and sand to the fatty mixture. If the adjustment will take place in small portions, then the proportions should be written down immediately, and then, after selecting the best option, use data for mixing large quantity material for

Clay cleaning

After carrying out experimental activities and leaving the clay elements to dry, you can move on to cleaning the clay from pebbles, plant roots and other inclusions that will interfere with normal work and reduce the quality of the masonry joints.

Clay cleaning can be done in two ways:

1. Grinding and sifting clay through a metal sieve, which should have cells no larger than 3 mm. Dry clay does not grind well, so the whole process will take quite a long time.

2. If you choose another method of cleaning - “wet”, then before carrying out it you need to soak the clay and wait until it swells and becomes soft. Then, the resulting solution is rubbed through a sieve with a three-dimensional chain-link mesh with 3 mm cells, through which it is convenient to rub a medium-thick clay solution.

Soaking clay

Before you start cleaning with the “wet” method, the clay needs to be soaked. It should immediately be noted that dry-cleaned clay is soaked in exactly the same way before mixing the solution.

Dry purified or uncleaned clay is poured into a container. Typically, old bathtubs are used for this or wooden boxes are made, then covered with metal roofing sheets. To ensure that the clay gets wet well and is easier to mix, it is poured in layers of 120÷150 mm, each of which is spilled with water and mixed. Upper layer pour water so that it covers the mixed clay.

The soaked clay is left to swell in this form for a period of 14 hours to a day. During this time, it can be stirred periodically with a shovel, adding water if necessary.

Then, the whole mass is mixed, water is added to it, and it is again left for 14-24 hours. After this period, the composition is mixed again, and if it is made from pureed clay, it can be immediately used to prepare masonry mortar. If crude clay has been soaked, it is passed through a sieve into a container prepared for this.

Fireclay clay

For some sections of the furnace, which will be discussed below, fireclay clay is used for masonry. This clay in finished form It is unlikely that you will be able to find it on your own, since it is produced using a special technology consisting of several stages:

• Ordinary soaked clay, enriched with various additives, is formed into briquettes and dried.
• Next comes the firing stage - this process takes place at a temperature of 1200÷1500˚С.
• Burnt briquettes are ground to a flour state to obtain fireclay clay, and to a coarse-grained fraction to obtain sand.

Due to the fact that fireclay material is subjected to high-temperature firing, it is fireproof and can withstand temperatures above 1800˚C.

Fireclay clay contains highly dispersed hydroaluminosilicates. During the manufacturing process, this material, thanks to sintering and firing, acquires the following characteristics:

• Hygroscopicity averages no more than 7.8% of the total volume of clay.
• Humidity content - no higher than 5%.
• Fire resistance reaches 1530÷1830˚С.
• Fraction size from 0.005÷0.01 mm.

The special qualities of fireclay clay give the mortar based on it high plasticity, and when dry, it acquires the strength of stone.

Making a solution from this material will not cause any difficulties, since in a dry state it is, in fact, ordinary clay, but already crushed and purified. Therefore, it is pleasant to work with such clay, and the mixing process consists of the following steps:

• Clay powder is poured into a prepared container, for example, a 10-liter bucket. Then a small amount of water is poured into the clay and kneaded well until smooth. If necessary, a little more water can be added to the solution, and then it should be left for 2.5-3 days to swell.
• After this period, water is added to the solution and it is mixed well, the mass should have the consistency of thick sour cream. It should be noted that when making this solution, there is no fear in pouring water into it, since this can easily be corrected by pouring a small amount of dry clay into the resulting mass.

In addition to regular fireclay clay, in specialized stores you can find ready-made instant compositions, which are mixed immediately before laying. Using such building mixtures, you do not have to wait three whole days for the clay to swell.

What solutions are needed for the oven?

Not all novice stove makers know that not one, but several solutions are used for laying the stove, since different sections have different heating temperatures.

The attached diagram identifies individual zones of the furnace structure in which different clay mortars can be used for masonry.

1 – The foundation of the furnace is built on the basis of cement-sand mortar, but around it you can make a waterproofing layer, a kind of “castle” 100÷150 mm wide from clay, which must be compacted well.

2 – Waterproofing from roofing felt sheets is laid on the foundation.

3 – The first two brick rows are usually placed on cement-sand mortar. Sometimes a little lime is added to it for greater plasticity.

5 – The heat-storing zone of the furnace is laid out on a clay-sand solution that can withstand temperatures of 500÷600 degrees - this is how much this zone can be heated.

6 – The combustion chamber of the furnace is made of fireclay bricks, and a solution of fireclay clay is used for its laying, since the temperature in this area of ​​the heating structure can reach 1 thousand degrees.

7 – Laying the source of the chimney is done using a clay-sand mortar. In this area, the oven heats up to 300÷400 degrees.

8 – The chimney fluff, located under the ceiling of the room, is laid out on a clay-sand mortar.

9 – Metal box, arranged for fire safety around the pipe, can be filled with sand, expanded clay, vermiculite or the same clay-sand mortar.

10 – Cervix chimney laid out on a cement-sand mortar with the addition of clay.

11 – The pipe head, exposed to atmospheric precipitation, is usually laid out on a cement-sand mortar.

If the solutions are made independently and used in combination, you can save up to 12–15% on their purchase.

Making solutions using clay

In addition to the fact that you will need to find, dig up and clean the clay from impurities, you should also know how to properly make oven solutions.

This table presents the materials that are used for and the proportions of the solutions.

Types of solutions	Clay mortar	Mortar	Cement mortar
Materials used	Consumption of ingredients in volume parts
Sand	4	2,5	3-4
Fireclay clay	1	-	-
Regular clay	1	-	-
Lime	-	1	-
Cement M400	-	0,5	1

We will not dwell on cement-sand and lime mortar - they are not included in the content of this publication. We are only interested in clay-based compositions.

Clay-sand mortar

As is already clear from the above diagram, the “lion’s share” of the areas of the heating structure are laid out on a clay-sand mortar, which is why it can be called the main one in the construction of the furnace. The materials from which this mixture is made have a fairly affordable price in specialized stores, but can also be obtained independently - in this case they will cost almost free.

The most popular solution for laying a furnace is clay-sand mortar.

Despite the low cost, clay-sand mortar has amazing properties, ideal for the construction of furnaces:

• Medium density, which is very important for its expansion when heated.
• Heat resistance up to 400 degrees.
• Maximum gas density.
• High fire resistance.
• Clay mortar can be reused if it was not used for laying the combustion chamber.
• The mixture can be prepared with a reserve, since its shelf life is unlimited. If moisture evaporates from the solution over time, you just need to dilute it with water and mix well.
• The material is environmentally friendly, which is important for indoor use.

The disadvantages of clay-sand mortar include its hygroscopicity, which means that it cannot be used for pouring the foundation and laying the upper part located on the street.

As mentioned above, in order for the solution to be plastic, serve for a long time, and be comfortable to work with, you need to correctly select the proportions of its components, which will depend on the fat content of the clay.

• In order for the mass to be homogeneous, without lumps or inclusions, the clay, swollen after soaking, is mixed well using a construction mixer, a shovel, or by trampling.
• While stirring the clay solution, sifted sand is introduced into it, in previously determined proportions, and, if necessary, water is added.
• The readiness and plasticity of the solution is checked using a clean metal spatula, along which the captured mass should slide easily.
• It is also very important to ensure that the mixture has maximum adhesion. To check this quality, the solution, in a layer of 7–8 mm, is applied to a brick, on which a second brick is placed on top and pressed. In this case, excess mortar is squeezed out, which is immediately removed, and the seam should be about 5 mm.

The bricks are left to dry for 30–40 minutes, after which the quality of their adhesion can be checked. To do this, you need to take the resulting “structure2” by the top brick and lift it, that is, create conditions so that the bottom brick is suspended. If the bottom brick holds on to the mortar, then the adhesion of the materials is considered optimal, that is, the mortar is of high quality and suitable for laying the stove.

The correct consistency of the finished solution can be checked by performing the following manipulations:

• A spatula or trowel soaked in water should be lowered into the prepared mass of solution. If the solution sticks to it, then the mixture is very greasy and should be “thinned” by adding a small amount of sand. After this, all the components are mixed again, and the test is carried out again. This is done until the desired consistency of the solution is achieved.
• If water appears on the surface of the finished solution, made in an ideal consistency and left for some time without stirring, this means that the clay used in it has insufficient fat content. In this case, you need to add a small amount of clay, which has a high degree of fat content, to the solution and mix the resulting mixture well again. In this case, the proportions of the ingredients used in the composition change, that is, the amount of sand decreases and the solution becomes fattier.
• If a spatula is lowered into a solution of normal fat content, and the mixture does not stick to it at all, this indicates that it lacks plasticity, which means that some more fatty clay needs to be added to the mass.

Video: example of preparing clay stove mortar

Clay-fireclay mortar

As mentioned above, fireclay material has increased resistance to high temperatures, reaching up to 1800 degrees, therefore solutions made with its use are used for laying the firebox, where it is in constant contact with an open flame. In a solution mixed using fireclay sand, the main component is still clay, so its shelf life is also unlimited. Even a completely dried solution will “come to life” with the addition of water and will be ready for use.

To mix the solution on which the walls of the combustion chamber will be laid out, you can use the following materials:

• This can be fireclay clay, used in its pure form or with a small addition of sand.
• Regular white or gray clay of normal fat content.
• Regular clay that is too oily can be “thickened” by adding fireclay or quartz sand to it in a 1:1 ratio, or by selecting fractional parts of the ingredients.
• If a heating structure model with a moderate heat load is selected for construction, such as, for example, a conventional hob, “Dutch” or Russian stove, then for laying the firebox it is quite possible to use a regular clay-sand mortar with a small addition of fireclay sand.
• For a furnace with a high heat load, the solution is made up of two components. It uses 70÷75% fireclay sand and 25÷30% ordinary clay. This mixture is mixed in the same way as a regular clay-sand solution:

— Ordinary clay is cleaned and soaked for 2.5–3 days.

- After this, the mixture is thoroughly mixed.

— Sand is gradually added to the mixed clay, and the mixture is brought to a homogeneous state and the desired consistency.

— When moisture evaporates from any clay solution, it is renewed by adding water.

Entirely made of fireclay refractory bricks, the best solution for its laying there will be a mixture of fireclay sand and clay, or completely made of fireclay clay.

From all of the above, we can conclude that with a “modest” budget, you can find an opportunity to save on the ingredients of the solution for building a stove. Of course, it would be easier to go to the store and buy everything you need ready-made, but if you want, refrain from extra costs, you can always find such an opportunity.

IN brick oven There are zones with different degrees of temperature and chemical stress, and it is correct to use different solutions in them with different characteristics. For example, it is better to place the firebox on a mortar with the addition of fireclay sand - clay-chamotte or cement-chamotte. They can withstand temperatures from 1100°C to 1200°C, and at high temperatures they are sintered into a single whole with brick, forming a monolith. The rest of the oven can be placed on a clay-sand mortar. Its characteristics are optimal for this (withstands temperatures up to +450°C, has high density, does not conduct gases). Some parts require greater strength (the chimney and the base of the stove); when laying them, some cement or lime can be added to the mortar. So there will be not one mortar for laying the stove, but at least three.

Almost any solution is made based on clay. For the body of the furnace, a certain amount of sand is added to it. Moreover, you can say exactly how much exactly by only “feeling” the source material (in the literal sense) and making a number of test batches with different amounts. Based on the test results, the best ratio is determined. Only this way, and no other way. This is the only way to create the right solution on which the stove will stand for a long time.

Where to dial

To save money, you can collect clay from your own plot. This is permitted by law (from a depth of up to 5 meters). You just have to dig about 2-3 meters to get to deposits with more or less acceptable characteristics. The second option is to collect clay in the nearest ravine, on a steep river bank, etc. This is no longer permitted by law, but is practiced everywhere. And the third option is to buy clay in a store or from stove makers, but you will need to determine its qualities and prepare it in the same way as if you mined it yourself.

So, we go into a ravine, to the river bank, or dig into a hole in the garden. If you look at the structure of a clay quarry in cross-section, you will see a number of layers. The top layer is usually fertile, with a lot of organic matter And plant residues. Even if its main component is clay, it is definitely not suitable for us. The required layers lie below. Maybe under a layer of sedimentary rocks, maybe under loam (clay with a very high sand content). We descend significantly lower - 1.5-2 meters deeper than the lower edge of the fertile layer. The color of the desired clay can be any - from whitish and gray to red. It is not important, the characteristics are important.

The fat content of clay layers increases from top to bottom. Ideally, material should be taken from middle layers. Here, as a rule, there are clays of medium fat content, and they are optimal for the main solution. For fireclay, you will need to take a certain amount of very light and oily clay from the lowest layers.

Determination of fat content on site

We determine the fat content right on the spot. Take a piece of clay from some layer (smaller than a fist). We wet our hand, squeeze the lump, and try to knead it. We wait until the water is absorbed. Repeat until the clay becomes plastic. We roll up the ball, begin to compress it from above and below with two smooth, even plates (pieces of wood, metal, etc.). As the process progresses, cracks begin to appear. If they began to appear only after the lump was compressed by 1/3, then the solution is either normal or oily and this layer can be used. If before, the clay is thin, and it’s better to try something else, because grinding out sand is a long and very tedious task, requiring a lot of water.

From the selected layer (or layers) you will need to take about 5-6 kilograms of clay. They are needed to determine the amount of sand in the mortar for laying the furnace. The main thing is not to forget which clay is from which place and not to mix it up.

Sand and water

You can, of course, buy sand. It is usually sold divided into fractions. You will need at least two - 0.7-0.9 mm and 0.15-0.25 mm. They are required in a ratio of 1:2.

To save money, sand can also be found in the same places where there are clay deposits. If you are lucky to find white - quartz, it can be used for any solution, and yellow - crushed feldspar, not suitable for masonry of the firebox, but suitable for other parts.

The best clay for laying a stove is white or kaolin. Sand can also be found between layers of clay.

You need soft or completely desalted, purified water. You can collect and settle rainwater ahead of time, or you can buy/collect purified water. It is important that it be soft or medium hard (hardness no more than 10 points). A large amount of salts greatly degrades the quality of the solution.

Sand preparation

If you mined the sand yourself, you must first sift it through a sieve with a fine mesh (1-1.5 mm). This separates large impurities and debris. Screened sand contains a lot of living creatures and alumina impurities, which can significantly deteriorate the quality of the solution. You can get rid of them by washing. A special apparatus is made for this.

Take a pipe with a diameter of 150-200 mm. Its length is three times the diameter (450-600 mm). A drain is formed in the upper part, water is supplied from below. The container is filled 1/3 with sand, the water pressure is adjusted so that the sand swirls in the upper part, but does not drain. Rinse until clean water begins to drain, waiting another 5-10 minutes to be sure.

The washed sand is laid out on oilcloth, tarpaulin or other dense material, into some container. You can dry it, you can use it wet, but when kneading it is necessary to take into account its moisture content.

Determining proportions

You need to work with the selected clay samples - select the amount of sand, check them, reject the worst ones, leave the best ones. Too many samples can confuse you. If the kolobok tests were given different results, leave the one in which cracks appeared after it was compressed by a third. In this case, there is a high probability that you have found deposits to which you will not need to add anything. You just need to dilute it with water to the required consistency. The time savings are huge.

If you can’t decide exactly, leave two, maximum three samples. This will already be a large number of batches and many tests.

How much sand is needed in the mortar for laying a stove?

Since we brought normal or oily clay from the quarry (if everything was done correctly), we need to determine how much sand needs to be added to it. This can only be done experimentally. The procedure is as follows:

We leave everything to dry, not in a draft, without access to sunlight. After 2 days, we wrap one rope from each batch around the handle of the shovel and look at the number and depth of cracks that appear. In a normal composition, the dried out crust and the slightly inner, still wet part should crack. In a skinny person there are many cracks and they are very deep, in a fat person they are mostly superficial. So we choose formulations with normal fat content.

How to determine the appropriate clay mortar composition

To confirm our assumptions, we test the second clay sausages. We pull them by the ends to the sides, tearing them apart. For a normal composition, the thickness at the break point should be approximately 1/5 of the original (if the thickness was 15 mm, then the diameter at the break will be 3 mm).

These tests usually yield two or three suitable compounds. Having rejected those that are not suitable, the buns and cakes are left to dry. This takes up to 20 days. Then we drop them from a meter height, see which composition turns out to be the strongest - it will be the best.

For a long time? Yes. But this is the only way to find the most durable mortar for laying a stove. If you really don't have time, you can skip these tests. But you will definitely need to check whether the fat content of the solution is chosen correctly. This is done after dilution with water (described in the “Quality Control” paragraph).

How much water

In the stove business, it is important that the mortar for laying the stove also has an optimal viscosity, which depends on the amount of water. We make a test batch from the half that was set aside. Soak it, rub it through a sieve, add sand according to the proportion found. If you can’t stir properly, add a little water.

They mix the clay with a board or a “veselka” - a board planed in the shape of a small oar. Once we have achieved homogeneity, we perform a simple test.

We take a trowel and run it along the surface of the solution with its edge. If the mark remains “ragged”, add a little water, stirring thoroughly. If the edges of the furrow left float, a lot of water has been poured. You must wait until the water settles and appears on the surface. Then it can be collected. The second way is to knead some more of the obviously “dry” solution and mix everything. With normal consistency, the clay solution under the trowel has flat surface, the edges of the grooves keep their shape.

Quality control and storage

After you have mixed a test batch of clay mortar for laying the stove, we test it again:

• Take a trowel, put a little solution on it and turn it 180°. A normal solution hangs calmly in this position, a thin solution (lots of sand) falls.
• Rotate the trowel with the solution 90° (edge ​​down). A normal solution slowly slides down and falls, leaving a thin, almost transparent film of clay on the metal. If the solution is greasy, it hardly slides off, or leaves a thick layer on the metal.
• We take two bricks. We apply a 2-3 mm layer of mortar on one, put the second one and tap it with a trowel, as when laying. Leave for 7-10 minutes. We grab the top brick and lift it up. If the second brick hangs and does not fall even with active shaking, then the mortar was made well.

If all tests went well, you can mix a large amount of clay mortar according to the proportions found. The finished clay solution can be packed in buckets or poured into barrels and closed with a lid. In this form, without changing the quality characteristics, it can be stored for months.

Features of preparing solutions for other parts of the furnace

As has already been said, to lay a good sauna brick stove, in addition to clay, you will need two more mortars: with fireclay for the firebox and with cement or lime. for pipe and base.

How to prepare a solution with fireclay

To prepare mortar for laying the firebox sauna stove you need to choose clay from the lowest layers - very oily. It is usually almost white, light gray or slightly yellowish. Fireclay sand or mortar is added to the soaked and rubbed clay (must be purchased at the store). You will need a lot of sand, and it costs a lot. To save money, it can be mixed with quartz (white) in a 1:1 ratio.

Since the clay is obviously oily, test batches are made by adding a large amount of sand at once - from 3/4 or more. When mixing this solution, high demands are placed on the quality of water - it must have a hardness of no higher than 8 points. When preparing fireclay mortar, you only need to determine the required amount of sand. Strength tests are unnecessary - fireclay is a guarantor of the required qualities.

Is it possible to use a ready-made mortar for laying a firebox with fireclay? It is possible, but it costs a lot of money, and you will need quite a lot of it.

Lime or cement-lime mortar

The base of the furnace and the fluff of the chimney are made from a solution with increased mechanical strength - with the addition of lime and/or cement.

To prepare a solution using lime, you need lime dough. Not self-slaked fluff, but a paste-like mass made by professionals. This is the material on which it is better not to skimp. It is advisable to buy it ready-made, packaged in airtight containers (check the expiration date). When you extinguish fluff yourself, particles of quicklime remain in the paste. During operation, they absorb water vapor, are extinguished, and tear the seams. Therefore, it is more advisable to use ready-made lime dough, and of good quality.

Lime dough does not have to be bought in buckets, you can buy it in bags

To prepare lime mortar, self-extracted sand, sifted through a sieve with a mesh size of 1 mm, is suitable. There is no need to rinse it, since lime will destroy all microscopic living creatures, and alumina impurities will not affect the strength of the solution either. If the sand is purchased, then its fraction is 0.7-0.9 mm. You can use any drinking water, including tap water. There are no requirements for rigidity, but process water It still cannot be used with impurities.

Preparing lime mortar for the stove

Open the container and knead the dough using a smoothly planed wooden paddle. You begin to add sand in portions, achieving its uniform distribution throughout the entire mass. The “starting” amount of sand is 1/2 of the volume of lime. After mixing everything, look at the fun. A solution is considered normal if the layer of solution on the surface is 2-3 mm, with possible small tubercles and streaks. If a very thin, almost transparent layer remains on the surface, through which even the wood is visible, the solution is thin (too much sand). If the layer is large and loose, there is not enough sand, the solution is too greasy.

Lime mortar can be kneaded using a drill, but the fat content must be tested using planed wood. This is how fat content is determined most accurately.

When determining the proportions of lime mortar, we take more sand, but the plasticity rate remains. Experts first bring the solution to a slight “fattiness” by adding up to 5 parts of sand to 1 part of the dough, and then bring it up to standard by adding clean paste. In this case, the strength of the seam is ensured precisely by the grains of sand, and the lime only glues them together.

We check the viscosity (amount of water) using two bricks. We lay about 3-4 mm of mortar on one, the second brick on top, tapping lightly with the handle of a trowel, we level it. A bead of mortar about 1-2 mm thick should form on the sides. If it stands and does not drain, everything is fine. The solution was mixed properly. If there is no roller, the solution is not squeezed out, you need to add a little water. If, on the contrary, the roller floats down, there is too much water, add paste (sand, as agreed, was placed along the maximum border within the limits of plasticity, so a small amount of paste will not hurt).

Cement-lime mortar

The proportion of cement in this solution is very small. For one part of cement, take at least 9 parts of lime paste (and no more than 15). Cement grade - from M200 to M600. The higher it is, the less this component is required, but the strength of the mortar increases when using high-quality cement. You can use a ready-made adhesive composition for ovens as an additive. Its main component is high-quality cement.

The whole difficulty is that this solution has a short shelf life - it must be used within 45 minutes from the start of mixing. Therefore, it is necessary to conduct experiments with the amount of sand and water on a test batch (all actions are similar to determining the lime composition). When mixing the working cement-lime mortar for laying the furnace, all pre-measured components are quickly mixed in a certain order. Ready material immediately put to work.

You can mix the solution with the same paddle, or you can use a drill with an attachment. The mixing procedure is as follows:

• First, add water to the lime (if this is necessary according to the test results), stir until smooth. Mix with a mixer for about 2-3 minutes, manually for 10-15 minutes.
• Continuing to stir, add the required proportion of cement in a thin stream. Having achieved homogeneity of the composition, stir several more times.
• Continuing to stir, gradually add sand. Having poured out the entire required volume, stir a couple more times. The solution is ready for use.

All these subtleties were developed experimentally. The technology is different from that used by our ancestors. They beat clay. For laying a simple cooking stove, just broken clay will do, but for a sauna stove with its temperature conditions A good, strong solution is required.

Kiln clay is used in different situations: for home and outdoor stoves, barbecue and fireplace. Unlike other compositions, the resulting mixture is economical and has good stability characteristics. Naturally, such a result can only be achieved with precise selection and preparation of the components, as well as following the technology of mixing the mixture.

To prepare a high-quality solution from clay, you need to select all the components correctly.

You will need several basic components:

1. Clay. This is the most important ingredient, it is the one that gives the mixture the necessary properties: viscosity, heat resistance, fire resistance. Not all types of material are suitable for this event: different variants(especially those found in nature) contain many additives that can spoil the final result. It is not always possible to get rid of such impurities, and it can also be a very labor-intensive task. And since the main factor when constructing furnaces is tightness, the selected material is pre-tested and carefully checked.
   Clay is the main ingredient in the manufacture of heat-resistant masonry compounds

   On a note! Clay can have normal, medium and high fat content.

2. Sand. It is an equally significant component of the solution. Material obtained independently can also be used for work, but it must be thoroughly cleaned and sifted. As a result, the sand should contain only homogeneous particles without impurities.

   Unlike quarry sand, river sand is considered the cleanest

3. Water. Many people mistakenly believe that this ingredient does not require special preparation; this leads to the loss of qualities of the composition when the temperature first rises. Only clean, well-settled water without foreign inclusions is suitable for work.

   It is advisable to use clean drinking water for the stove solution.

Each component is prepared in advance in required quantity, preferably with a small margin.

Features of the resulting mixture

Clay mortar has certain limits in its area of ​​use. The hottest areas are the most suitable for use: combustion and heat-storing parts of the structure. This is explained by the fact that the resulting solution withstands perfectly high temperatures and direct exposure to flame, but quickly becomes unusable when exposed to condensation or significant mechanical loads.

On a note! Due to its reliable adhesion, the clay composition can last for many years even under conditions of intensive use at temperatures up to 1000 o C.


Clay mortar has been used for laying stoves since time immemorial.

Advantages:

• Environmental friendliness. All components are of natural origin and do not emit substances harmful to human health.
• Availability. The components can be obtained, prepared by hand, or purchased at a reasonable price.
• Easy to dismantle. If it becomes necessary to move or replace a section of the furnace, the work will not require significant effort. The mixture is easily removed, and the bricks remain clean and intact.

But obtaining the necessary positive properties will require serious effort and time.

Methods for checking the quality of clay mortar

Before preparing the mixture, you need to determine the proportions of the components depending on the fat content of the selected clay, this will help to avoid problems in the future. When producing large quantities of material, correcting errors can be extremely difficult.

To determine the fat content of the main ingredient, do the following:

After the experimental batch of the composition is ready, it must be tested.

The fat content of the clay is determined by the plasticity of the samples.

Method 1

This technology is not particularly difficult. Each of the five parts is rolled into a small ball and kneaded into a flat cake. This is easy to do by placing it in the center of your palm and applying pressure with the fingers of your other hand. All resulting cakes are marked with appropriate pieces of paper on which the proportions of sand are indicated.

It will take 2-3 days for the fragments to dry. Initially, a visual inspection is carried out: the cake should not have cracks and collapse when compressed. If you drop it on the floor, it should remain intact. Based on the results of the experiment, the correct ratio of sand and clay is determined.

Method 2

Balls with a diameter of about 3 cm are rolled, each of which is placed between two carefully planed boards. Gradually, without unnecessary effort, pressure is applied, and the result is periodically checked. If the ball immediately began to crack, then it is a lean mixture; if cracking occurred when squeezing halfway, then the composition is too fatty. The optimal ratio of the components is when most of the ball is flattened and does not collapse.

Checking the fat content of the composition by squeezing a clay ball

There are other ways, but general principle everyone has the same.

How to properly prepare clay for laying a stove

Based on the experimental results, appropriate conclusions are drawn. If the fat content is high, the amount of sand should be increased by at least 1.5–2 times; if it is low, on the contrary, it should be reduced.

The ideal proportions of clay and sand for laying stoves are 1:1; this solution is plastic and heat-resistant. But it is necessary to dilute the mixture, focusing on the intermediate result. Classic recipe involves adding ¼ liquid, but depending on specific situation the amount of water can be increased.

The quality of the solution can be determined by the number of cracks in the dried sample.

Advice! If it is not possible to accurately select the proportions of the ingredients, then cement and salt can be used as an additive (for 10 kg of clay, 1 kg of cement and 150 g of salt).

Clay preparation

Based on the volume of work, we are preparing required quantity main substance. But before preparing the solution, the material undergoes preliminary preparation:

If after 48 hours small lumps are observed, then everything is mixed again, ground and left for another 24 hours.

Mixing the solution

The finished clay material can be mixed using several methods, each of which takes into account the characteristics of the substance:

You can determine the quality and readiness of the solution using tactile sensations. The resulting material is rubbed by hand: when a homogeneous rough layer is formed on the fingers, the mixture can be used. Externally, the composition should resemble thick sour cream, then the stove will be reliable and will serve for many years.