Modeling clay without firing

Cleaning from impurities

Once the required material is selected, it must be subject to cleaning procedure. In this way, everyone can improve quality characteristics. There are several cleaning methods:

• You can sift dry clay through a sieve with 2-2.5 millimeter mesh. This is a rather long tedious method, since the mass quickly clogs the holes.
• It is much faster to wipe the mixture diluted in water through a mesh with larger cells.

The second method is more convenient, especially since you still can’t do without soaking. This procedure is performed before or after cleaning, depending on the chosen method.

Finally prepare the ingredients as follows: required amount The material must be distributed in a special container in a layer of 15-20 centimeters and completely filled with water. On top is another layer of the same thickness. The procedure must be repeated until the container is full. You need to stir the mixture once a day, adding water if necessary. This completes the preparation. After 2-3 days you can start working.

The quality of the furnace’s masonry, its tightness, heat resistance, and durability over the years depend on a properly mixed solution. A shortage or excess of any component leads to its cracking, loss of integrity, and carbon monoxide leakage. For work use ceramic brick, and it is the clay mortar for laying the furnace that is homogeneous in composition with it. It provides a uniform structure of the structure with the same physical properties of mortar and brick. That is why clay solution is considered the best.

How to mix clay mortar?

The proportional composition of the binder components determines the purpose of the mixture: masonry or finishing. They may consist not of one binder, but of two, for example, clay and cement. The filler imparts rigidity to the hardened mixture, and a slight excess of it does not harm the quality of the masonry. Even a small excess of binder (in this case, clay) reduces the strength. That is why it is believed: the less it is in the solution, the higher its quality. However, it is better not to replace it with cement and lime; this is done only in cases where there is no clay.

The consistency of the mixture should be sufficiently plastic, viscous, but not liquid, and even more so, it should not crumble. The furnace body should not have thick masonry joints, optimal thickness 3-4 mm. The sand grain should not exceed 1 mm. However, it is also possible to use coarser sand, but then its quantity will change.

The exact proportions depend on the quality of the clay:

• skinny requires reducing the volume of sand,
• oily is diluted in a ratio of 1:2 (clay:sand).

So, the proportions for fine sand and high-quality clay are 1:1. Mixing various additives will lead to their change in the direction of decrease.

Supplements

Salt and cement are added at your discretion. The standard composition of the mortar for laying the furnace does not provide for their addition. However, if you decide to make a complex mixture, the proportions are as follows (per 10 kg of clay): salt 150 g, cement M400 1 kg. And also: clay 2 buckets, sand 2 buckets. This quantity is enough to lay 100 bricks.

Sequence of work:

• clay is poured into a trough, poured with a small amount of water and allowed to soak for 6 hours to 2 days;
• it is stirred regularly during this time (you can put on rubber boots and trample the clay); in total you will need 1/4 of the total volume of clay;
• add sifted sand and mix with a shovel; if the mixture slowly slides off the shovel, this is its optimal consistency.

Definition of plasticity ready mixture carried out in the following way: they mold a flagellum 1.5 cm thick, 20 cm long. Connect it into a ring around wooden blank with a diameter of 5 cm. The flagellum should stretch evenly. If it breaks, the ends of the tear should be sharp. The absence of cracks on the fold means that the mixture is too oily; if multiple ruptures occur, the solution is thin. In the first case, sand is added, in the second, clay. It is necessary to achieve the formation of several small cracks on the bend.

Types of lime mortars for stoves

For the chimney, it is not advisable to use a clay mixture in the part that rises above the roof. Due to the formation of condensation, the clay cracks and collapses. In this case, the preparation of mortar for laying stoves is carried out on the basis of lime paste. The same mixtures are used for laying the foundation for the furnace.

Solution composition:

• sand 3 parts,
• lime dough 1 part.

Lime paste is prepared by combining 3 parts water and 1 part quicklime. It has a plastic consistency, similar to softened fatty clay. The density of properly prepared lime paste is 1400 kg/m3. For masonry stove chimneys and foundations they buy it in finished form in construction stores.

Lime slaking is carried out in special factory workshops in lime slaking machines. It is not recommended to make the dough yourself, as lime causes burns to the skin and respiratory tract. To maintain your health, you must apply strict safety measures: wear gloves, goggles, a respirator, and dust-proof clothing.

The fat content of lime dough affects the amount of sand added. Too greasy will require up to 5 parts of sand to achieve the normal consistency of the solution. Before combining the components, the dough should be rubbed through a sieve with 1x1 cm cells. To achieve the required consistency, add water.

Strength can be improved by adding cement. The resulting lime-cement mixture with two binders and filler also has high moisture resistance. The following proportions of mortar for laying the stove, foundation and chimney allow you to achieve its best quality:

• cement 1 part,
• sand 8-10 parts,
• lime dough 2 parts.

The sequence of work is as follows: cement and sand are mixed separately. Lime dough is diluted with water until it becomes viscous. Then the mixed dry ingredients are added to it and mixed. For viscosity, water is again added in small portions.

Concrete and heat-resistant concrete mixtures

Concrete mortar is also used for the stove foundation and chimney above the roof. Its strength is not inferior to limestone, hardening begins after 45 minutes. Before mixing, the components are sifted through a sieve. First, sand is poured into the container, and cement is placed on top of it. Stir until smooth, then add water. It is important to achieve a viscous consistency, not thick and not too runny.

For a monolithic firebox, a heat-resistant concrete mixture is used. Its composition is as follows:

1. Portland cement M400 1 part,
2. crushed brick 2 parts,
3. sand 2 parts,
4. fireclay sand 0.3 parts.

Strength increases if you use quartz sand instead of ordinary sand. Refractory concrete is characterized by large fractions (up to 10 cm) and high density. The following proportions are used as standard: 8 liters of water per 20 kg of mixture. Mixing is carried out mechanically, for example, in a special mixer.

You can also use a shovel, but then the quality will be lower, since it is impossible to achieve good uniformity manually. It is not advisable to increase the amount of water, as this will reduce physical properties mixtures. At the same time, stirring is continued even if there is confidence that there is not enough water. It is necessary to work with such a solution quickly due to its rapid hardening.

On average, when laying stoves, three buckets of mortar are required per hundred bricks.

Ideally, clay mortar and brick are almost the same in composition and can withstand heat of more than 1000 degrees. Professional stove makers determine the quality of the clay for the mortar by touch and carry out the laying with a joint thickness of 3-4 mm. With thicker seams, the clay between the bricks does not withstand high temperatures and crumbles, cracks form into which air is sucked in, which means traction worsens, fuel consumption increases and there is a danger of carbon monoxide escaping into the living room.

The golden rule of kiln work is that the less clay in the kiln masonry, the higher its quality.

One of the basic rules of the stove maker, inherited from our ancestors: the less clay, the better quality masonry And yet, clay is the most noble construction material, because it gives room for error. If masonry with cement mortar cannot be disassembled without loss, then stove masonry with clay mortar can be disassembled easily and without waste. At repair work brick and facing material laid on clay mortar can always be preserved.

There is an opinion that the strength of clay mortar can be increased with the help of various additives. For example: for 10 kg of clay - 100-150 g of table salt or 1 kg of cement.

However, our great-grandfathers hardly used cement, and their furnaces stood for a hundred years or more.

If the components are correctly selected, the clay solution does not require any additives, and all kinds of recommendations are just a safety net.

The mortar for masonry should be plastic, moderately greasy, or, as they say, normal. The greasy solution dries, decreases in volume and cracks. Skinny does not provide sufficient strength. Clays for preparing mortar come in different fat contents or plasticity. There are clay deposits from which a solution of normal fat content is prepared without adding sand. Sometimes you have to mix two or three clays taken from different places, and strictly dose them.

First they are mixed dry, then mixed with water. If the clays turn out to be oilier, then sand is added to them, the amount of which can range from 0.5 to 5 parts by volume. The most common ratio of clay and sand in the finished solution is 1:1 or 1:2. The amount of water is approximately 1/4 of the volume of clay. Fatty clays will require more sand, which should be fine-grained and free of foreign impurities. The sand is first sifted through a fine sieve with a mesh size of 1.5x1.5 mm, at least. Very thin clays have to be washed by removing excess sand.

There are many ways Clay quality testing.

One of the simplest: form a ball from the prepared solution and throw it on the floor. If the ball crumbles, it means there is a lot of sand and little clay in the solution; if cracks appear in the resulting cake, it means there is still a lot of sand. If the ball does not show a single crack, the solution is normal or greasy.

First way.

Take 0.5 liters of clay, add a little water to it and knead it thoroughly with your hands until it completely absorbs water and sticks to your hands. Having prepared a stiff dough, roll a ball with a diameter of 40-50 mm and make a flat cake with a diameter of 100 mm from the same ball. Dry them under normal conditions for 2-3 days. If cracks appear on the ball or cake during this time, it means the clay is oily and requires adding sand. If, after drying, there is no crack on the ball or cake, and the ball, falling from a height of 1 m, does not crumble, then such clay is suitable for preparing a solution. Lean clays do not crack, but do not have strength; fattier clays must be added to them. Sand or clay is added in several stages, each time checking the quality of the resulting solution.

Second way.

Take 2-3 liters of clay, place it in some container, fill it with water, knead the lumps and mix with a paddle. If the clay sticks strongly to the funnel (completely envelops it), then it is oily. Sand must be added to such clay. If individual clots remain on the jig, then such clay is considered normal, and a solution is prepared from it without adding sand. If the oar is covered with a thin layer of clay, it means that it is skinny and requires the addition of fatty clay in certain quantities.

Third way.

This is the most accurate way to determine the quality of clay needed to make bricks. 0.5 liters of clay is kneaded until the dough becomes thick and thoroughly kneaded with your hands, as indicated in the first method. Roll the prepared clay dough into a ball with a diameter of 40-50 mm by hand, place it between two smooth (planed) boards and gently press on the top one, gradually squeezing the ball. The compression is repeated until cracks form on the ball. In this case, the degree of fat content of the clay depends on the amount of flattening of the ball and the nature of the cracks that form.

A ball made of lean clay (loam) breaks into pieces with slight pressure on it. A ball of clay slightly fatter than loam will crack when compressed by 1/5-1/4 of its diameter. A ball of normal clay cracks when compressed by 1/3 of its diameter. A ball of oily clay gives thin cracks when it is compressed by 1/2 of its diameter.

From the same clay dough as the ball, they roll it out by hand into flagella 10-15 mm thick and 150-200 mm long. The flagella are stretched or bent in the shape of a ring around a round and smooth wooden rolling pin with a diameter of 40-50 mm.

A flagellum made of fatty clay stretches smoothly, gradually becomes thinner, forming sharp ends at the point of rupture, and does not form cracks when bent. A flagellum from normal clay stretches smoothly and breaks off when its thickness at the break point becomes 15-20% less than the thickness of the flagellum, and when bent, small cracks form. A flagellum made of lean clay stretches little, gives an uneven break, and when bent, forms many cracks and tears.

Two or three times repeated testing by crushing the ball, stretching and bending the flagellum allows you to select normal clay suitable for making raw bricks or mortar for laying stoves.

When testing, you have to mix two or three clays, adding sand or, conversely, removing it. Only with this selection can you find the best proportions of certain materials

Still, it is better to err on the side of the fat content of the solution. This is not significant for the operation of the furnace. Conversely, excess sand in the solution can affect the strength of the masonry. The fattier the solution, the more cracks the plaster will produce, but they can be eliminated by grouting with a leaner solution (with more sand added) and whitewashing in several stages.

After the sand and clay have been collected, what remains is prepare the solution correctly R.

First way.

To prepare the solution, the clay is soaked for 2-3 days in a large wooden box lined with tin, or in a special iron “trough”. Then they put on rubber boots and, gradually adding sand, trample it until not a single lump of clay remains. You can also break up clay lumps using a special tamper. Then the solution is felt with your hands and the remaining pieces of clay are crushed (or removed). A well-mixed solution, where sand and clay are in the right proportion, should slide off a steel shovel or trowel, and not stick to it. If applied to brick even layer mortar (3-4 mm), put a second brick on top, pressing it (knock), and after about five minutes try to lift the top one, then when good quality The bottom solution should not come off. If you dip a stick (the handle of a shovel, etc.) into a normal clay-sand solution, then an insignificant mark will remain on it. A very greasy solution will leave a kind of film on the stick; skinny - will not leave any traces at all.

Second way.

When the clay is normal in fat content and does not require the addition of sand, then do this. They make a boardwalk or shield measuring 1.5 x 1.5 m, called a striker. It is not recommended to mix clay on the ground, as soil and various impurities will get into it. Layers of clay are poured onto the firing pin and moistened with water. As soon as the clay softens, it is shoveled several times, raked into a pile in the form narrow bed height 300-350 mm. The length of the bed depends on the amount of clay. Then blows are applied to this bed with the edge of a wooden shovel, as if cutting off slice by slice of the plate from the bed. The impacts cause the lumps to break and become crumpled. Round stones and foreign impurities are removed during operation. Then the clay is shoveled again, raked into a bed and crushed again, striking with a shovel. This operation is repeated 3-5 times until all lumps are broken.

If sand is added to clay, then do this. They pour sand in the form of a wide bed, make depressions in it, pour clay in layers, moisten it with water and fill it with sand on top, wait the required time until the clay softens. Then it is shoveled repeatedly with sand, collected in a bed and crushed with a shovel exactly as described above. You need to knead the clay for so long until it is completely mixed with sand and becomes homogeneous. In this case, there should be so much clay in the solution that it can only fill the gaps between the grains of sand.

Well mixed solution with the right amount sand and water should slide off the steel shovel, but not spread over it. To the touch it is a slippery mass, uniformly filled with sand, without clay or sand clots. This solution has one drawback: large particles often remain in it, making it difficult to make thin seams and also injuring your hands. While working, you have to constantly probe the solution with your hands, removing all kinds of foreign particles, and this makes the work difficult and slow. It is best to strain this solution through a fine sieve.

Third way.

If clay of normal fat content is used, which does not require the addition of sand, then it is poured into a box or barrel in layers, moistened with water, and poured on top. The clay soaks for several hours. Then it is thoroughly mixed and filtered through a sieve with 3x3 mm mesh. By adding water at the workplace, the required density of the solution is achieved.

When sand is added to clay, all components are measured in the required doses. The materials are sifted separately. After the clay is soaked, it is filtered, sand is added, mixed and filtered again.

Clay solutions should be stored in a closed container so that foreign objects do not accidentally get into the solution. Time spent sifting materials or straining mortar pays off handsomely when laying stoves.

For centuries, the skill of the stove maker was carefully passed on to descendants. The subtleties of the device and carefully thought-out procedures were scrupulously conveyed to future generations. Craftsmen patiently taught their students the art of constructing brick units and revealed the secrets of producing binders. Improved old recipes are still used at work. In order for the “hot heart” of the bath to serve long years, you need to know how to prepare a solution for laying a stove, where to find cheap raw materials and clearly calculate the proportions.

Furnace design and correct solution

A brick sauna stove is a large structure, parts of which operate under uneven conditions. The humidity and temperature values ​​operating at the base of the unit differ significantly from similar parameters near the firebox and chimney.

The temperature “fork” during the period of active operation can vary from 0º to 1200º or more. The firebox and chimney are persistently attacked by flue gases, and the latter also has to repel the onslaught of rain, winds, and frost.

So far, such a thing has not been invented by man in nature. mortar, which could adequately resist the listed destructive factors. Cement and lime individually and together are not capable of maintaining such an impressive temperature range. Clay below the mirror groundwater, simply becomes limp, and the excessively porous lime composition allows gaseous combustion products to pass into the steam room, washing room and rest room.

For a normally functioning structure brick oven At least three masonry mortars with different properties will be required. There is no point in using fireproof, very expensive binding mixtures for the chimney. They are needed for structural components exposed to intense exposure to high temperatures. There is no reason to use heat-resistant materials in the construction of the largest heat-storing part. Instead, relatively inexpensive ready-made clay for laying a stove or a completely free mixture mined and created with your own hands is suitable.

Solutions for the construction of all structural parts brick stove can be purchased in factory packaging. They are extremely simple to use: just read the instructions on the package and add the required amount of water. The proportions are thoroughly calculated and selected. True, the cost of ready-made building mixtures cannot be classified as humane.

Significant expenses do not bring joy. On average, 2-3 buckets are needed per 100 bricks, depending on the thickness of the seam and the density of the masonry. Elementary calculations for upcoming construction rarely bring pleasure to thrifty owners. We would like to introduce you to the recipe for preparing budget masonry mortars, available for handmade production.

Types of masonry mortars

Solutions are mixtures consisting of one or two binder components and filler with water. The binding components are clay, cement, and lime paste. The filler in the furnace industry is silicate sand or fireclay sand. Water is taken without impurities and technical contaminants. Clean tap, well or lake water will do. The best solvent masonry mixtures are considered to be rain or thawed versions.

Solutions differ in porosity, gas conductivity and thermal properties. Their common characteristics must be ease of application, easy-to-use plasticity and stable strength after hardening. According to the classification of old stove makers, masonry mortars are divided into the following groups:

• Fatty - having excellent plasticity, but cracking after drying.
• Normal - characterized by average ductility and strength, suitable for reliable masonry.
• Skinny - characterized by fragility, low ductility and strength, crumbling after drying.

If the mixture contains only one binder, for example, cement or clay, the solution belongs to the category of simple solutions and is designated as a 1:1 ratio; 1:2.5 or 1:3, etc. The ratio tells us in what proportions the components are taken. The first number indicates the binder component, the second number indicates the volume of filler. If there are two binder components in the solution, the ratio looks, for example, like in the complex cement-lime version 1: 2: 8. The proportion of the most effective binder is indicated in the first place.

It is clear that stove makers need solutions with normal plasticity and the same strength. However, you should not give up fatty and skinny people. The fatty variety is brought to normal by increasing the sand content, the lean variety is brought to normal by enriching it with an astringent component.

Apart from pouring a reinforced concrete base under the foundation, the following solutions are used in the construction of furnaces:

• Lime. Used in masonry brick foundation stoves and Those. suitable for the construction of those parts of the sauna unit that will not be subjected to heating above 450º-500º. The seams are strong, but not fireproof enough. But the pipe elements, attacked by atmospheric phenomena, laid out using lime composition, turn out to be quite wear-resistant.
• Cement-lime. Applicable only for foundation construction, because not heat resistant enough for chimneys, able to withstand temperatures of no more than 250º.
• Cement-chamotte. It is mixed from cement with heat-resistant fireclay sand and water. It is used in the construction of the combustion sector, because withstands temperatures up to 1300º without destroying the substance. It does not allow flue gases to pass through, but does not prevent the escape of condensate. It is heat-resistant, fire-resistant, easy to use, but expensive, which is why prudent bathhouse owners most often give preference to its analogue with a clay component instead of cement.
• Clay-fireclay. It is used in the masonry of fireboxes; the properties of the solution are similar to the previous representative, but it is cheaper due to the inexpensive or completely free binding component.
• Clay. It is used in the masonry of the main part of the furnace, which accumulates heat and transfers it to the room being treated. The clay composition is distinguished by average heat resistance. The seams created from it can withstand temperatures up to 1100º. Hardening of the mixture occurs by evaporation of water from the composition. When wetted, the solution again acquires plasticity and makes it possible to sort out the furnace for the purpose of repair. The clay composition is used in the construction of the source of the chimney. However, it cannot be used for laying parts that extend beyond the building due to the likelihood of getting wet from atmospheric moisture.

The predominant part of the furnace is built using clay version, attractive at a budget price. The relatively low price of a factory product can mercilessly deceive. The expense is impressive.

The components of this mixture can be obtained for free. We literally trample them underfoot. Therefore, it is better to find out how to make your own mortar from clay from sand for laying a stove, and how to save a significant amount without putting in too much effort. In addition, the clay component can be useful in the production of a mixture for the combustion segment.

Homemade mortars

Before you start making masonry mixtures, you need to stock up on a simple tool for stirring. Among stove makers it is called a oar because it really resembles a rowing device. This is a board hewn on both sides with a uniquely hewn handle. You will need a shovel, a mixing container, ideally wooden barrel or a tub; if you don’t have one, a metal one will do. You will need 5-7 buckets, a trowel to determine plasticity, two sieves with cells of 3 mm and 1.5 mm, as well as components of future building mixtures.

We extract cheap clay

Those who want to minimize costs should stock up on clay and sand. They are not only included in the basic mortar for laying the furnace body, but are also used to adjust the plasticity of the mortars. Clay is useful for the refractory mixture used in the firebox.

Clay is a natural finely dispersed material that acquires plasticity when saturated with water. Its plasticity depends on the content of small and dusty particles in the rock: the more of them, the fattier the clay. If the clay contains more than 40% sand, then it is called sandy or lean.

For the production of masonry mixtures in natural form it doesn't fit, the seams are too fragile. The optimal content of sand particles is 37-38% - this is the norm. If there are fewer of them, the rock can be “normalized” by adding simple or fireclay sand.

There are three ways to prepare clay:

• Soak factory-produced raw brick. To do this, unfired building material is placed in a tub with clean water. The soaked mass is filtered using a fine sieve, then sand is mixed into it. The required consistency is achieved by adding water.
• Buy broken rock from the local population, probably dug up in the garden. To obtain suitable raw materials from it, you will have to work hard. Typically, such material is heavily contaminated with organic matter, which is removed through repeated soaking, sifting and straining.
• Get it yourself. Clay deposits are found everywhere. Having gone 4-5m deep, it is quite possible to dig it on your own site. However, it is better to walk along steep river banks, ravines and similar outcrops. Taking a closer look at the section (cut of a bank or ravine), you can identify individual rock layers without any problems.

Measure approximately 5m from the surface and pinch off a piece of rock for “field” testing. Remember the lump, it should wrinkle like plasticine, without sticking to your hands. Try rolling it into thin “sausage”-type flagella. If you managed to roll up a flagellum 5-7 cm long and 4-5 mm thick and bend it into an arc without breaking it, you have taken the right path as a procurer. If not, continue searching for suitable material in the outcrop being examined or find a similar location.

The color of the rock does not matter; it depends on mineral inclusions, which have virtually no effect on the plastic qualities of the material. However, the most suitable is considered white clay, called kaolin. It can be used in the manufacture of clay mortar for masonry fireboxes sauna stove. The most common are gray, bluish- and greenish-gray clays. There are frankly chocolate and earthy breeds. Don’t let the rusty or brown tint scare you, this is just evidence of the presence of iron oxides.

Experienced stove makers can determine clay with suitable plasticity without laboratory testing. Beginning masters will have to find out their suitability experimentally. To do this, you should select equal 5 portions of the breed, approximately 0.5-1 liters each.

Stocking up on free sand

Packaged or bulk sand, sorted by grain size into fractions, can be freely purchased at construction market. Or you can get it and prepare it with your own hands for introduction into the future mortar for laying the furnace. It is advisable for buyers of the finished product to give preference to the mountain or lake version, because the roughness and angularity of their grains of sand will improve the adhesion of the mixture.

The regulated thickness of the seams of the stove masonry is 2-3mm, which means that you should buy material of a fraction of no more than 1.6-1.8mm. Stove makers recommend that in addition to sand with the specified size, you also purchase smaller material. Mortar with different grain aggregates adheres more firmly.

Those who want to dig up sand themselves will certainly have options in the surrounding area: abandoned quarries, ravines, river shallows, steep bank outcrops, etc. It must be taken from a depth of at least 1-1.5 m, so as not to bother with washing the organic matter. If you still extract sand with foreign inclusions, it should be washed running water, for this:

• We pour sand in portions into a bucket, which we then fill tap water from a hose.
• We stir up the soaked material in a bucket with a piece of board or a paddle and drain the muddy slurry that floats to the top.
• We repeat the process until the refilled water becomes transparent and absolutely clean.

The washed and dried sand is sifted through a sieve with a mesh size of 1.5 mm.

Methods for determining clay plasticity

Now is the time to remember the clay samples taken to determine suitability for plasticity. Place them in different containers and mix with water. Add it gradually so that you get a stiff clay dough that does not stick to your palms.

We mark the samples with serial numbers to know how much sand was added and how it affected the plasticity:

• Let's leave the first one as is.
• In the second we mix 10%.
• In the third 25%.
• In the fourth portion 75%.
• To the fifth sample we will add 100% sand, i.e. an amount equal in volume to clay.

Add sand in several stages, stirring gently after each addition. If you introduce a large amount of sand, you will have to add water. From each sample it is necessary to make experimental samples: two or three balls Ø 5 cm and the same number of cakes 2-3 cm thick. The samples, according to the numbering, must be laid out to dry in a room protected from drafts. After 8-10 days, the cakes with balls must be checked and determined which sample has the optimal composition.

A solution that satisfies the following conditions is considered suitable for masonry:

• If the ball dropped from a height of approximately 75cm-1m above the floor does not break and does not become colored when pressed.
• If the dried samples do not have noticeable cracks.

Two or three samples were made so that the experiment could be carried out several times.

There are two more methods of determination with a similar division into five parts and equivalent preliminary preparation, according to which:

• Each sample should be rolled into balls Ø 5 cm. The prototypes are alternately placed between two boards that serve as the working parts of the press. When the boards are compressed, a ball of plastic clay will decrease by 1/2 of its diameter with the appearance of minor cracks. A sample with average plasticity will “sag” by 1/3 with the formation of noticeable cracks. The skinny material will only shrink by 1/4 or less and crumble.
• From each sample you need to roll out sausage flagella about 1.5-2 cm thick and 25 cm long. They should be slightly stretched and bent around a wooden rolling pin or the handle of a shovel up to 5 cm in diameter. A sample of thin clay breaks off almost immediately and does not stretch. A sausage of average plasticity will break when the stretching and deformation section decreases in thickness by 20%. It will crack at the folds. A rope made of plastic clay will not break and will stretch smoothly.

The simplest tests should indicate to us the proportions of a mixture of medium plasticity, according to which we will prepare the masonry mortar. Masonry mortars will require 1/10 of the volume of the stove or a little less.

Preparing clay mixture step by step

Before mixing the solution, immerse the crushed clay in a barrel or similar container and fill it with water. It needs to soak for a day, preferably two. If after two days of soaking there are still lumps, you can extend the procedure for another 24 hours. Mix the softened rock thoroughly to form a mass reminiscent of sour cream. If necessary, add water and strain the dough before using.

Prepare a mixture from creamy clay dough and sifted sand in the following order:

• In accordance with the proportions verified experimentally, we measure out the clay and sand in buckets.
• Pour the ingredients into a convenient container in portions, distributing them so that the raw materials are stacked in several layers.
• Mix the components of the mixture with a shovel repeatedly and intensively, adding water if necessary.

Mix until the masonry mortar resembles a homogeneous, loose dough. Let's check the consistency of the mixture with a shovel: the solution should seem to slide off the bayonet without spreading. You can store it in any container under a “lid” made of a piece of roofing felt, polyethylene, plywood, etc. There is no need to part with the solution remaining after work; its shelf life is unlimited - just add water.

Second folk method will require the use of physical force. Essentially, the raw material will need to be beaten with a board or paddle. Because plant debris and gravel inclusions will still be knocked out of the mixture; they do not need to be sifted first. We will place the sand in a bed according to the proportions wooden shield area 1.5x1.5m. Bed width up to 35cm, height up to 25cm. We will make a depression in the middle of the bed and fill it with soaked and crushed clay.

We shovel the laid raw materials, pouring sand into the clay from the edges until the mixture becomes homogeneous. Then we again form a bed, which we backhand and forcefully “chop” with the edge of a wooden oar. We strike often to break up all the lumps. After processing is complete, add water if required.

How to make lime mortar

The lime mixture is used when laying the stove foundation and chimney outside the roof. The preparation container needs such a volume that it can accommodate the lime, which increases three to five times during the slaking process.

The starting material is poured with water and waited for thickening, periodically stirring and breaking the lumps with a paddle. The resulting lime dough is diluted with water so that the consistency becomes similar to sour cream. Then sand is introduced in portions until the solution clots begin to stick to the oar.

The mixture is stored for several days; when the consistency changes, water is added to it. To save yourself the hassle of making lime dough, you can buy it ready-made.

Firebox masonry mixture

To make a refractory mortar, you need plastic white clay; slightly yellowish or gray clay is suitable. Fireclay sand or a cheaper mixture of quartz and fireclay sand is used as a filler. You need to take them in equal shares. Plastic clay does not need to be tested before preparation; it can be immediately mixed with clean, soft water.

Video instruction on how to use a mixer

A video on the topic “How to prepare a mortar for laying a stove with a mixer and how to make it correctly” will clearly present the manufacturing process:

Described by us simple ways and recipes for masonry mortars for the stove will help to significantly reduce the costs allocated for the construction of the main bath unit.