What kind of mortar is needed for masonry stove

Tips on how to properly prepare mortar for masonry stove of bricks

Stove heating is not diminishing in popularity. Firstly, there are still many ungasified areas with nowhere to go, and secondly, it is much cheaper to heat using a stove, and thirdly, stove heating is several times more environmentally friendly than centralized heating. To build a stove that will last for decades, you need to consider a lot of nuances, but the greatest difficulties often arise with masonry mortar. Preparation of mortar for masonry brick oven is not as easy as the usual cement-sand mortar, which is widely used in minor repairs. The operating conditions of the furnace are complex: its different parts are exposed to temperatures from.30 to 1000 0 C, and that’s not counting wind loads, so ordinary cement mortar, alas, will not cope. Different compositions are used for different elements of the furnace, and the final result depends not only on the preparation process, but also on the quality of raw materials, and all this is important to consider.

The furnace is a responsible structure, the strength and durability of which depends not only on the bricks chosen for it, but also on the mortar with which these very bricks are fastened. At the same time a number of negative factors act on the furnace, and since there is no single masonry mortar that would cope with both frost, and with the highest temperatures and icing, you have to use different compositions:

  • cement-lime or lime mortar can be used for the foundation, which takes the brunt of the load, but will not experience particular thermal effects;
  • For the heat-accumulating part of the furnace, which is exposed to temperatures up to 600 0 C and the combustion gases, the best solution is clay mortar;
  • for the furnace part, where temperatures are maximum and chemical exposure is not strong, you can take a clay or earthenware mortar;
  • For the chimney origin, which is exposed to temperatures up to 400 0 C, a clay mortar is suitable, while a lime mortar is suitable for the chimney;
  • for the chimney, where the temperature is not high, but there are wind loads, lime mortar will do, some even allow ordinary cement.

1 foundation, 2 firebox, 3 flue, cladding, 5 chimney

Choosing a mixture for installation of stoves and fireplaces

Installation of furnaces and chimneys is not an easy process. Construction of this kind of complex and fire-hazardous structure requires the participation of professional qualified stove installers. However, there will always be brave and persistent fans of the stove business, folk craftsmen, relying only on their own strength and skills. We will tell you how to choose a stove mix or prepare it yourself.

In any case, you should know that it is of great importance to use a quality mixture for masonry and stove lining. Used masonry mortars directly affect the reliability and durability of the stove or fireplace. Therefore, it is essential to use a furnace mixture of high quality and suitable for the type of heating installation.

Types of masonry furnace mixes

Heat-resistant mortar. Such stove masonry mix has a good resistance to high temperatures. When cooled, it retains its chemical properties and structure. No irreversible deformation occurs in this process. The described mixture does not lose its load-bearing capacity even when heated.

Heat resistant mortar. Under the influence of high temperatures this mixture does not expand and does not change its properties. In the heated state, the mixture retains all its characteristic mechanical properties. Mortar is more resistant to thermal deformations, compared to the heat-resistant mixture. Perfectly holds both static and dynamic loads.

Refractory mortar. Is it heat-resistant or heat-resistant? Refractory furnace mixture can withstand not only high temperatures, but also the influence of chemically aggressive substances in the exhaust gases.

Only fire-resistant and heat-resistant masonry mortars should be used for any type of stove, even for stoves not heated more than 400°C. To make do with ordinary mortars in this case is impossible and extremely dangerous, since the destruction under the influence of high temperatures of the furnace or chimney, often leads to fires.

Mixtures for individual furnace structures

To all mortars used in masonry furnaces have the following requirements:

  • Thermal resistance, which ensures the safety of the furnace and the possibility of its full operation;
  • Elasticity necessary to prevent cracks in the furnace walls.

Masonry mortars for furnaces are also subdivided according to the type of components. Among them can be noted mixtures based:

Structural foundations. The base of the furnace is constructed using a lime or cement-lime mixture. If there is excessive moisture below the foundation, a cement mix should be used. It is sufficiently resistant to moisture.

Chimney. The part of the structure that is above the roof needs to use lime or lime-gypsum mortar. To speed up the curing of the mixture, it is recommended to add gypsum to it. Those who prioritize the strength of the construction, it is worth including cement in the composition.

The body of the construction. For the construction of this part of the furnace, it is necessary to use a solution that includes sand, water and clay. And the clay should be sufficiently fat.

Lime-gypsum mixture

The main components of this mortar are sand and lime dough, which is a mixture of quicklime and water in a ratio of 1:3. Lime mortar can be bought or prepared with your own hands. In the first case, you will be guaranteed the high quality of the material, the advantage of the second is the optimal cost.

Building the Vortex Masonry Stove

To prepare the mortar, it is required to sift sand, mix it with the lime dough in a ratio of 1:3 and add such an amount of water that the mixture should be as thick as sour cream.

Next, the mortar is tested for elasticity. To do this, you need to use a wooden bar. By stirring the mixture with it, you can determine the next state of the mortar:

  • A lean mortar if there is no mixture left on the wood at all. This means that a little lime must be added;
  • Normal mixture, if the extracted wooden plank is covered with a film of the mixture or lumps of the same;
  • Oily mortar, if a thick layer of the mixture is stuck on the slat. In this case, more sand should be added to the mixture.

The mixture based on lime has its disadvantages. This prolonged drying of the masonry and the adverse effects of the material vapors on the human body.

Cement mixture

A normal cement mixture includes sand, cement and water. The brand of cement determines the choice of the proportion of components. First you need to mix the cement with the sand. Only then add water.

Complex mixtures are prepared by adding additional ingredients. If it is lime dough, then the use of the resulting mixture should not be delayed. Mixed mortar should be prepared in the following proportions: one part cement, 1-3 parts of other ingredients and 6-15 parts of sand.

If you add Portland cement and broken bricks to the usual cement mortar, you get a mixture of the heat-resistant type.

Clay mix

To build the body of the furnace, you must prepare the clay mixture It should be homogeneous, without lumps, of a sour cream consistency. If the mortar is prepared poorly, it will crumble while using the stove. It is also impossible to achieve beautiful masonry joints.

Before proceeding to the preparation of the mortar, it is necessary to check the fatness of the clay. To do this, take about 2 kg of material and pour water into it. After stirring the resulting mixture with a wooden bar, conduct a visual inspection of the latter:

  • strongly adhering clay on the trowel is an indication of its high grease content. It must be sharpened with sand;
  • Small pieces of clay remaining on the slat indicate that the mortar is normal and that there is no need to add sand to it;
  • The clay film, which covers the wood, is an indication of thinness and suggests the addition of greasier clay to the mixture.

The clay mixture is consumed as follows: for 100 bricks about 25 liters of mixture are required. The best mixture for stove bricks is the one that has the most similar composition to that of the bricks used. High-quality clay mortar can withstand 800-1000C without cracking and without losing strength properties.

To achieve a stronger mortar, you can add ingredients such as sodium chloride and Portland cement:

  • Sodium chloride (table salt) is added in an amount of 100-150 g per bucket of mixture. The resulting mortar should be well mixed;
  • the mixture includes 0.5-1 kg of Portland cement for the same amount of clay mixture.

The amount of clay and sand in the mortar may vary within the range of ratios: 1:1 1:2. In this case, water takes a quarter of the added clay.

Ingredients for the mixture can be prepared by yourself or by purchasing ready-made materials. The following types of clay are now sold:

  • white clay, suitable for fireproof mortars and used for wood-burning stoves with a furnace mode not exceeding 1000C;
  • Chamotte clay, used for masonry of stoves with any temperature regime.

Prepared mixes for stove installation

It is cheaper to prepare the ingredients for the masonry mixture yourself. However, this option is the most time-consuming. To make this process faster, easier and more reliable, it is advisable to use ready-made masonry mixes.

Now in the Russian market there are many foreign and domestic manufacturers of ready made oven mixes. You can easily choose and buy the furnace mixture. Manufacturers, as a rule, produce mixtures different in composition and purpose :

Among the numerous list of such materials, it is worth noting the following:

Plitonit range of mortars for construction of stoves and fireplaces. Plitonit joint venture, manufactures mixes by German technology on the territory of Russia. The range includes mortars with heat-resistant reinforcing fibers for fireplaces, heat-resistant mortars for masonry and repair of stoves, fireplaces and chimneys, as well as mortars and glues for plastering and revetment.

BOSSNAB is a brand of St. Petersburg company that produces furnace mixes based on red clay. Our product range includes refractory and heat-resistant mortars for stove laying, stove plaster mixes and adhesives for tiling.

Terracotta. Russian manufacturer of masonry mixes for construction and repair of stoves, fireplaces and chimneys. Mixtures Terracotta is safe for the environment and humans, heat-resistant, plastic material, whose main binders are kaolin clay, sand, and chamotte. Terracotta withstands heat up to 1300C.

RATH is an Austrian company that produces refractory mixes in Europe: Germany, Austria, Hungary and Poland. Produces a large variety of refractory and heat-resistant building materials, including furnace mixes for various applications: refractory concretes, plastic masses, adhesives and mortars.

Vetonit is part of the international Weber organization with production in 64 countries. The company is headquartered in France. Among the variety of the company’s products is represented by Betonit laying mortar, consisting of clay, cement, sand and additional components, which has found application in the arrangement of the interior space of stoves and chimneys made of red bricks.

Makarovs’ Stove House. One of the best masonry mixes produced in Russia. The company grew from a small workshop in Dresden to a small workshop in Milan. Kastorome, whose founder established the production of stove masonry mixes for his own needs and fellow stove-makers. Taking into account the quality of the mixture, the products were in great demand among professional stove and fireplace builders, and as a result the company started to manufacture the products on an industrial scale. Nowadays Makarovs’ Stove House produces masonry mixes from environmentally friendly materials, based on red and blue Cambrian clay.

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SEV Russian company producing dry mixes for masonry stoves and fireplaces. The company’s production facility is located in the city of Kiel. Borovichi Novgorod region.

Certain rules should be followed in the process of application of the prepared mixtures:

  • Mixing is done with a mixer only.
  • The mixture should not be kneaded again after it has set.
  • The mixed material must be consumed within 60 minutes.
  • The ambient temperature during the construction of the furnace must be at least 10C.
  • Do not heat the ready-made stove earlier than 3 days after completing the laying process. This is due to the fact that the composition of the mixes include substances that delay the drying of the mortar and, consequently, exclude the possibility of cracking joints.
  • The stove pipe must be laid with a special mixture, which can be identified by a marking on the package.
  • No sooner than one month after the stove is put into intensive use should the facing be done.

To eliminate efflorescence at the masonry joints, which may form after the first use of the stove for its intended purpose, use a damp rag. But only after the heater has cooled down completely.

Self-made mixtures are cheaper than ready-made materials. However, the latter have a number of advantages. Therefore, each of you must make a choice independently in favor of one or another option, based on your preferences and capabilities.

How to choose a mixture for masonry brick oven

A private home is difficult to imagine without the presence of a traditional brick stove or a modern fireplace. These indispensable attributes not only provide the room with heat, but also serve as a fashionable interior decoration. To create a solid monolithic brick construction, special mixes are used, which have fire resistance, plasticity and very high strength. In this article, the master plumber will tell you how to choose a mixture for masonry brick oven.

When building a brick stove or fireplace, special compositions are used, to which there are special requirements. Heating structures are used in “extreme” situations where temperatures change to very high values. The duration of this exposure can be several hours, so the material must be adapted to such exposure.

In such a construction, special attention should be paid to the composition of the mixture. It must not contain any toxic components that could be released into the environment. It is also important that there are no specific odors. These products must comply with sanitary standards.

The special composition of the mixture allows the filling of gaps between the joints, which is a reliable barrier to the penetration of carbon monoxide in the heated space. Due to the absence of slots, there is no air dispersion and the draught is not impaired.

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These mortars are used in the following works:

  • Masonry brick exterior surfaces;
  • Furnishing the furnace chamber;
  • The construction of chimneys, including that surface that goes outside;
  • The pouring of the foundation;
  • Cladding;
  • Creation of additional elements exposed to high temperatures.

Depending on the destination chosen type and proportions of the composition.Types of masonry mortar mixes

Mixtures for stove masonry are subdivided into the following types:

  • Heat-resistant mortar. Such stove masonry mix has good resistance to high temperatures. After cooling down, it retains its chemical properties and structure. No permanent deformation occurs. The mixture described does not lose its load-bearing capacity even when heated.
  • Heat-resistant mortar. Under the influence of high temperatures this mixture does not expand and does not change its properties. The mixture retains all its characteristic mechanical properties when heated. Mixture is more resistant to thermal deformations, compared to heat-resistant mixture. Perfectly holds both static and dynamic loads.
  • Refractory mortar. It can be heat-resistant or heat-resistant. Refractory furnace mixture can withstand not only high temperatures, but also the effects of chemically aggressive substances found in exhaust gases.

In the construction of any furnaces, even those that are not heated more than 400 ° C, you should use only fire-resistant and heat-resistant masonry mortars. Conventional construction mixtures in this case is impossible and extremely dangerous, since the destruction under the influence of high temperatures of the furnace or chimney, often leads to fires.

Mixtures for the device of the individual structures of the furnace

The following requirements apply to all mortars used in oven masonry:

  • Thermal resistance, which ensures the safety of the furnace and the possibility of its full operation;
  • Elasticity, which is necessary to prevent cracks in the walls of the furnace.

Masonry mortars for furnaces are also subdivided according to the type of components. Among them can be noted mixtures based:

Construction foundation. The base of the furnace shall be constructed using a lime or cement-lime mixture. If there is excessive moisture below the foundation, a cement mortar should be used. It is quite resistant to moisture.

Chimney. The part of the structure that is above the roof needs to use lime or lime-gypsum mortar. To accelerate the process of hardening of the mixture, it is recommended to add to it gypsum. Those who prioritize the strength of the structure, it is worth including cement in the composition.

The body of the structure. A mortar consisting of sand, water, and clay must be used to construct this part of the furnace. And the clay should be sufficiently fat.

The main components of this mortar are sand and lime dough, which is a mixture of quicklime and water in a ratio of 1:3. You can buy lime mortar or prepare it yourself. In the first case, you will be guaranteed a high quality of the material, the advantage of the second is the optimal cost.

To prepare the solution, you need to sift the sand through a sieve, mix it with lime dough in a ratio of 1:3 and add such an amount of water that the mixture is as thick as sour cream.

Next, the mortar is tested for elasticity. To do this, you need to use a wooden plank. Stirring the mixture with it, you can determine the following state of the mortar:

  • Thin mortar if there is no mixture left on the wood at all. This means that you need to add a little lime;
  • Normal mixture, if the wooden slat removed from it is covered with a film of the mixture or lumps of the same;
  • Fat mortar, if a thick layer of mixture is stuck on the slat. In this case, you should add more sand to the mixture.

A mixture based on lime has its disadvantages. This prolonged drying of masonry and the adverse effects of fumes of the material on the human body.

A typical cement mixture includes sand, cement, and water. The brand of cement determines the choice of the proportion of components. First you need to mix the cement with sand. Only then is water added.

Complex mixtures are obtained by incorporating additional components. If lime dough serves as such, then you should not delay using the resulting mixture. The mixed mortar should be prepared in the following proportions: one part cement, 1-3 parts of other ingredients and 6-15 parts of sand.

If you add Portland cement and broken bricks to the usual cement mortar, you get a mixture of heat-resistant type.

To build the body of the furnace, you need to prepare the clay mixture It should be homogeneous, without lumps, sour cream consistency. If the mortar is prepared poorly, it will crumble in the process of using the furnace. It is also not possible to achieve beautiful masonry joints.

Before you start preparing the mortar, you need to check the oiliness of the clay. To do this, take about 2 kg of material and pour water into it. Having stirred the resulting mixture with a wooden bar, conduct a visual inspection of the latter:

  • Strongly adhering clay on the trowel indicates that it is highly greasy. It should be sharpened with sand;
  • Small lumps of clay remaining on the bar indicate that the mortar is normal and there is no need to add sand to it;
  • The clay film covering the wood is an indication of thinness and suggests the addition of greasier clay to the mix.

The clay mixture is consumed as follows: about 25 liters of mixture per 100 bricks. The best mixture for stove bricks is the one whose composition has the greatest similarity with the composition of the bricks used. Quality clay mortar can withstand 800-1000 ° C without cracking and without losing strength properties.

To achieve a stronger mortar, you can add ingredients such as sodium chloride and Portland cement:

  • Sodium chloride (table salt) is added in an amount of 100-150 g per bucket of mixture. The resulting mortar should be mixed well;
  • The composition includes 0.5-1 kg of Portland cement for the same amount of clay mixture.

The amount of clay and sand in the mortar can vary in the ratios: 1:1. 1:2. In this case, the water takes a quarter of the added clay.

Ingredients included in the mixture can be prepared by yourself or you can buy ready-made materials. Now sell the following types of clay:

  • White clay, suitable for fire-resistant mortars and used for wood-burning stoves with a furnace mode not exceeding 1000 ° C;
  • Chamotte clay, used for masonry ovens of any temperature regime.

For mortars used in the construction of a brick oven in the bath, such components are needed:

  • Cemented. the ratio of cement to sand is 1:3;
  • Lime. the ratio of sand to lime is 2:1;
  • Lime-cement. lime, sand, cement. 2:1:6-16.

These types of mortar will be suitable for the arrangement of the foundation, chimney and other areas, for laying the furnace area will need a mixture of clay and chamotte. The stove is plastered with these compositions:

To place a summer oven in the backyard of the cottage, for a barbecue, a mixture of refractory clay and sand or of heat-resistant cement, ordinary cement and mortar is used.

Mortar for construction of the furnace on the street is recommended to make on the basis of cement, especially in high humidity. 3 to 1 ratio of sand to cement.

It is cheaper to prepare the ingredients for the masonry mixture yourself. However, this option is the most time-consuming. To make the process faster, easier, and more reliable, it is best to use ready-mix mortars.

Currently in the Russian market there are many both foreign and domestic manufacturers of ready-to-use furnace mixes. You can easily choose and buy stove mix. Manufacturers, as a rule, produce mixtures different in composition and purpose:

Among the numerous list of such materials it is worth noting the following:

  • Plitonit. a range of mortars for building stoves and fireplaces. Plitonit is a joint venture that manufactures mixes based on German technology on the territory of Russia. The range includes mortars with heat-resistant reinforcing fibers for fireboxes, heat-resistant mortars for masonry and repair of stoves, fireplaces and chimneys, as well as mortars and glues for plastering and revetment.
  • BOSSNAB is a brand of St. Petersburg company that produces stove mixes based on red clay. The range includes refractory and heat-resistant mortars for laying stoves, as well as stove plaster mixes and adhesives for tiling.
  • Terracotta. Russian manufacturer of construction mixtures including those for building and repairing and tiling of stoves, fireplaces and chimneys. Terracotta mixes are environmentally and human friendly, heat-resistant, plastic material, whose main binders are kaolin clay, sand and fireclay. Terracotta endures heat up to 1300 ° C.
  • RATH is an Austrian company that produces refractory mixes in Europe: Germany, Austria, Hungary and Poland. Produces a large variety of refractory and heat-resistant building materials including furnace mixes for various applications: refractory concretes, plastic masses, adhesives and mortars.
  • Vetonit is a part of the international Weber organization, which operates in 64 countries worldwide. The company is headquartered in France. Among the variety of products represented by the company’s masonry mortar Vetonit, consisting of clay, cement, sand and additional components, which is used in the construction of the interior space of the furnaces and chimneys of red bricks.
  • Makarovs” stove house. One of the best masonry mixes produced in Russia. The company grew out of a small business in the town of Cheboksary in the north-eastern part of Romania, where it has been working ever since. Castorome, whose founder has established the production of stove masonry mixes for his own needs and fellow stovemakers. Taking into account the quality of the mixture the product became in high demand among professional stove and fireplace builders, and as a result the company started producing the product on an industrial scale. Nowadays Makarovs Stove House produces organic masonry mixes, based on red and blue Cambrian clay.
  • SEV is a Russian company producing dry mixes for masonry stoves and fireplaces. Production of the company is located in. Borovichi Novgorod region.
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During the application of pre-mixes, certain rules should be followed:

  • Mixing is done only with the help of a mixer.
  • Do not mix again after it has cured.
  • The mixed volume of the mixture must be consumed within 60 minutes.
  • The ambient temperature during the furnace construction should be not less than 10°C.
  • Do not heat the finished stove earlier than 3 days after completing its laying. This is due to the fact that the mixes include substances that delay the drying of the mortar and, accordingly, exclude the possibility of cracking joints.
  • The stove pipe must be laid with a special mixture, the nature of which can be identified by a note on the package.
  • The oven must be finished no sooner than a month after it is used intensively.

To remove efflorescence on the masonry joints that may form after the first use of the stove for its intended purpose, you should use a damp rag. But only after the oven has completely cooled down.

Self-made mixtures are cheaper than ready-made materials. However, the latter have a number of advantages.

How to prepare refractory mortar for laying a stove or fireplace

Wishing to save money without loss of quality, you can make a masonry heat-resistant mixture yourself on the basis of inexpensive mortar MSH-28 and sodium liquid glass.Materials:

The process of preparing a heat-resistant mortar

It is necessary to mix liquid glass with water in the ratio of 1:1. Mix well by shaking the components in the bottle. The desired amount of diluted liquid glass can be prepared at one time, and added to the solution as needed, since it does not lose its qualities.Next, it is necessary to make the MSh-28. It is necessary to use yellow mortar, not gray. For the latter, different proportions are needed. For 25 kg of MSH-28 6,5 l of water is poured. The water is poured from the top and a short pause is made so that it soaks into the mortar. This will eliminate the formation of lumps, which otherwise would have to be broken up for a long time. Then the mixture is mixed with a mixer to a homogeneous mass and left for at least 3 hours for the clay to swell. You can safely leave it over night, it will not harden, on the contrary it only gets better.

After swelling, the mortar is stirred again. Then a 250 mm solution of liquid glass with water is poured in. After that, the mixture is mixed with a mixer for at least 3 minutes. Do not pour 125 ml of liquid glass at once, because stirring it in a thick mass to a homogeneous consistency will take a lot of time and effort.

After waiting 20 minutes, you need to stir the mortar once again, and it is ready for use. With such a proportion it gets very convenient consistency for laying. The solution does not float, and at the same time is not too thick. It is a pleasure to lay on it. Although the mortar takes a long time to prepare, but if the work is properly scheduled, it won’t cause inconveniences. You can soak in water in the evening in a bag of 25 kg of MSH-28, and then in the morning, as required, to mix in the liquid glass and produce. Such a mortar is guaranteed to be heat-resistant and easy to work with, besides, it is not expensive, which cannot be said about ready-made ready-made ready-made mixes.

Mortar for stove masonry according to all the rules

As already noted, its ideal consistency should correspond to the thickness of sour cream. If fat clay is taken for it, then to 1 part should be added 2 parts of sand, if normal. the proportion should be equal.

Before proceeding to masonry furnace, it is necessary to check the quality of the resulting furnace mixture. To do this, you will need to fix with mortar 2 bricks, wait about 5 minutes, and then lift the top brick. If the construction does not disintegrate in a few lifts, the mortar for masonry brick oven is perfectly matched. If this did not happen and the bond quickly disintegrated, most likely, for the preparation of the mortar was taken lean (non-fat) clay.

Experienced bakers also advise to increase the strength of the solution by adding table salt to it (150 g per 10 kg of clay is enough). Here you can also add cement M400: 1 kg for the same volume of clay.

When the stage of work on the chimney begins, it will be better to replace the clay mortar with a lime-sand one: it is more resistant to moisture. To prepare it, you need to take 3 parts of sand and 1 part of lime dough. Alternatively, 1 part quicklime and 3 parts water.

Stove mortar for masonry. varieties

Appropriate compounds should be used to properly mason different areas:

  • clay. It is an inexpensive variant which enables the use of local resources. The composition provides the necessary strength and heat resistance at 1100 °C. The material is resistant to open fire and aggressive gases. Can withstand temperatures of up to 1,300°C with the addition of fire clay. Hardens when exposed to elevated temperatures. The prepared mixture can be used indefinitely. When drying, it restores characteristics after wetting with water;
  • lime. It has a higher price, because it involves the use of purchased materials. quicklime or quicklime. In terms of strength characteristics is slightly higher than the clay mixture. Characterised by an intermediate level of fire resistance. Parameters of heat resistance are limited by the temperature range at the level of 400-500 °C. Resistant to high humidity. Can be used within three days after mixing.
  • Cement. Cement-based masonry mortar is more expensive and harder than lime mortar. Cement M300 is used. If necessary, lime or chamotte should be added. Cement-lime mortar retains its properties in temperatures up to 250 °C and can let the gases flow through the pores. Cement-clay mixture has an increased heat resistance up to 1300 °C and does not allow flue gases to seep in. The prepared mixture should be used within one hour from the moment of mixing.

The stoves are placed on the clay mortar, adding a little salt or cement for strength

Factors affecting the quality of the mortar

The stage of preparing the mortar is very responsible, on which the quality and durability of the entire structure depends. The quality of the resulting mortar is affected by some factors that can be corrected:

  • Fat content of clay. Clay can be lean or greasy, with an incorrect ratio of components, the solution in the process of drying may crumble or crack. To avoid this, it is necessary to do a little testing, to determine the type of clay and the quantitative ratio of components. Testing can be done in several ways:
  • Of clay samples, after soaking them in water, rolled small bundles, 10 mm in diameter and 10-15 cm in length, which are winded on a mold with a diameter of 5-10 cm. If you use fat clay, the flagellum will gradually stretch, without the appearance of cracks. In the case of lean clay, the tourniquet will also stretch, but when it reaches reduced thickness parameters, it will quickly tear.
  • After making the clay mortar of creamy consistency, for 2 minutes a flat wooden plank is immersed in it. If at removal of the bar there is a mixture of more than 3 mm, the clay is considered too plastic and requires a large amount of sand. If the thickness of the clay layer is less than 2 mm, this type of material is not recommended. The optimal variant is a layer of 2-3 mm.
  • Clay and sand clogging. Only cleaned sand and clay are recommended for mixing a quality mortar.

The sand is cleaned as follows:

  • First of all, the sand is sifted through a sieve to remove large debris fractions;
  • Next, a semblance of a sucker for catching fish is made, using a metal circle and burlap;
  • having fixed the product on a firm stand, sand is poured inside;
  • Using a hose and a large head of water, the sand is washed out;
  • Run on DO until the water coming out of the net is clear.

The clay as well as the sand must be washed, for this purpose, these manipulations are carried out:

  • the required amount of clay is crushed into small fractions;
  • Pour the prepared material into the trough, placed at an inclination of 5-8 degrees, with respect to the floor. The clay is poured on the elevated part of it;
  • water is poured in the lower part of the trough to the level of the clay location;
  • Using a scoop or shovel, the clay is washed;
  • When a pasty substance is formed, it is transferred to any previously prepared container;
  • The washing process should be carried out until the necessary amount of clay is obtained.
  • Correct proportions of mortar components. In order to obtain a high-quality mortar it is necessary to correctly select the proportion of entering materials. Selection is carried out by the following methods:

Additives

Salt and cement are added as desired. The standard composition of the mortar for masonry furnace does not provide for their mixing. However, if it is decided to make a complex mixture, the following proportions are observed (per 10 kg of clay): salt 150 g, cement M400 1 kg. And also: clay 2 buckets, sand 2 buckets. This is enough for the masonry of 100 bricks.

kind, mortar, needed, masonry
  • In a trough poured clay, pour a little water and give it soak for 6 hours to 2 days;
  • stir it regularly during this time (you can wear rubber boots, stomp on the clay); a total of 1/4 part of the total volume of clay will be needed water;
  • add the sifted sand, mix it with a shovel; if the mixture slowly slides off the shovel, this is its optimal consistency.

Definition of plasticity of the finished mixture is carried out as follows: mold the flagellum thickness of 1.5 cm, length 20 cm. Put it in a ring around a wooden billet 5 cm in diameter. The flagellum should be evenly stretched. If it tears, the ends of the tear should be sharp. No cracks in the fold means that the mixture is too greasy; if there are multiple tears the mortar is skinny. In the first case, sand is added, in the second. clay. It is necessary to achieve the formation of several small cracks on the fold.

Clay mortar with their own hands

This kind of mortar is the most famous. It has been used since ancient times and was universally available. A mixture of clay and sand accumulates heat from the stove and transmits it to the room.

Masters have a classification of clay mortars according to their fatness:

  • Thin. mortars made of clay, which have low plasticity due to low percentage of fatness. When drying, they become thin and brittle. The stove construction, which is made using such mortar will not last long, because all the seams fall apart after drying.
  • Normal. characterized by good plasticity. They are strong, durable. They are the most suitable option for stove masonry.
  • Fat. mortars, in which the percentage of clay grease is quite high. Although they are plastic, but after drying there is a high probability of cracking.

4 different ways of preparation

The following methods of preparing clay mortar are best known:

  • First. Soak the necessary amount of clay in water 24 hours before laying. The solution is strained and sand is added. The resulting mixture is stirred well. If puddles of liquid clay are visible, more sand should be added until a homogeneous consistency is obtained.
  • The second. It is necessary to mix clay, which has heat-resistant characteristics, with fireclay sand. Mixing ratio: one to one. Pour as much water as the consistency of thick sour cream requires.
  • Third. This method requires loam. It is important to knead several versions of the mortar and choose the most suitable one. Ratios of clay, sand and cement: ten and one to one, then nine to two and one, ten to one and one, one to 0.one to one. Pour the mixture into the box and wait until it dries out. The flattest and densest version is good for building a stove. The clay mortar prepared by the third method can be used for masonry elements that will not be heated more than 600 degrees. When the temperature readings are higher, it will deform. Therefore, its use is limited to external masonry of stove elements.
  • The fourth method with various additives. Clay and sand must be thoroughly sifted. Mix the resulting mixture with water. Stir the mortar to a sour creamy consistency. To the sand and clay mixture add salt, observing the proportion of one to ten. The same amount of cement can be added. They can be dissolved beforehand, and only then added to the total solution. Additives will provide masonry strength and resistance to temperature and pressure.
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Rocket and Masonry Stove Mortar Discussion

Checking the quality of the mortar

Determine the necessary quality of the clay mortar can be determined by the following methods:

  • “Ball.”. You need to take 4 parts of clay. In the first add sand in a ratio of 4:1, then 2 to 1, 1 to 1, 1 to 1.5, where the first figure is the amount of clay, the second. the amount of sand. All mixtures are mixed to the same thick consistency. When the clay has reached the desired homogeneity, roll balls from it. These balls should be flattened with the palms of your hands. The resulting pellets are piled on the surface to dry. After some time you can determine the quality of each mixture.

When the material is completely dry, you need to determine the most suitable mixture for masonry. You should pay attention to such characteristics: cracking when drying, cracking under pressure, falling. The part that has passed all the tests and is not deformed has the most successful proportions. Choose these proportions and the bricks in the stove masonry will be fixed as firmly as possible, the joints will not crumble and will not fall out.

  • The “flagellum”. A piece of mortar is crumpled and rolled into a roll. The ends of the piece are stretched. If it stretches evenly, it is made of greasy clay. If it thins and gradually breaks up. the clay is normal. When the ends of the roll break unevenly. the clay is skinny.
  • “Paddle.”. To determine the best quality material you need a bowl where the mortar is prepared. It should be stirred with a spatula. If there is a layer of 0 on its surface.1 cm, more clay is needed. If it reaches 0. 2cm and clumps are formed. this is the best option. When the clay paddles more than 3 mm, it shows great fatness. The mixture requires the addition of sand.

Where to get free clay and sand?

You can not spend money to buy clay. It can be found by yourself on your own plot. But to do this you need to dig a 5 meter high pit, and only then start searching. The best place to find clay are the banks of streams and ravines.

If the material has no stickiness, but just crumbles, you need to continue looking. Clay rocks may differ in color. The most successful for construction is kaolin. white clay. But other types (brown, red, gray) are not bad for stove masonry bricks. The extracted material requires cleaning from various impurities and other particles.

You can get sand in quarries, ravines and shoals. The depth of occurrence. 1-2 m from the ground. After extraction, it is necessary to wash, dry and sift the sandy material.

How to calculate the correct quantity?

It should be remembered that the bigger the brick, the less mortar is needed for its masonry. And vice versa. The amount of mortar depends on the nature of the pores: the denser the brick, the less mortar will be needed. Consumption depends on the thickness of the joints: the more it is, the more material is needed.

Multiplying 75 by the area, you will get the necessary amount of mortar for the entire work. But it should be taken into account that such figures are approximate. You can prepare the mortar in portions, so it will be more convenient to determine the right amount of consumables and not to make a mistake up or down.

Using

There are no special recommendations. The mortar mixture of clay, which has been left for a couple of days, will dry. But it can be soaked. Re-soaked mortar in its characteristics is no worse than the newly prepared one.

Clay does not tolerate moisture. That is why you should not wet the bricks when using clay mortar. It is also worth protecting the masonry from further exposure to moisture.

Instructions for the use of fire clay

equipping a country house, many homeowners, wishing to create an atmosphere of comfort, antiquity, are built in homes fireplaces, Russian stoves. This requires special heat-resistant materials. Heat resistant fireclay bricks are used for masonry, and heat resistant chamotte clay is used for the mortar, the instructions for use of which should be attached to each package when selling.

Composition and characteristics of fire clay

and more often real estate developers when building country houses use natural materials for interior decoration. For heating we build old-fashioned stoves, fireplaces, creating a unique atmosphere of comfort from the live fire and crackling wood. To build these attributes of antiquity, you need to use building materials with great resistance to high temperatures. One such material is fire clay.

It is produced by a special technology, the end product is either highly dispersed hydroaluminosilicate powder, sold in building material stores, or bricks. For the production of fire clay is used white kaolin clay. Its main properties. high heat resistance, low plasticity. In the production of fire clay mixture kaolin is enriched by removing the hydroxides, iron sulfides and titanium.

Some properties of fire clay

In a special kiln at a temperature of firing, equal to 1340 ° C, from the raw material is removed excess moisture. The mixed mass gets the properties and appearance of stone. Further on the technology is crushing the resulting chamotte and grinding it to a powder state. It is this powder that is used as a binder in the preparation of mortar for masonry stoves and fireplaces. Due to its properties chamotte clay can also be used as a finishing material.

As for the chemical composition of the fireclay mass, its strict regulation is not expected. Only the presence of mandatory components is regulated:

Depending on the temperature regime, burnt kaolin acquires a white color and, possibly, some creamy shades. Sometimes the output is a powder of gray-brown color.

The main properties and technical characteristics of fire clay

The main properties and technical characteristics of chamotte clay, as well as other building materials, are regulated by the relevant standards. Despite the lack of strict regulation of the chemical composition, fireclay clay in its parameters must comply with the provisions of GOST 6137-8:

  • water absorption in the low-fired fire clay should not exceed 25%;
  • water absorption of highly fired fire clay should be in the range of two to ten percent;
  • moisture should not exceed 5%;
  • Grain size after grinding not more than two millimeters;
  • Heat resistance. not less than 1550 ° C and not more than 1850 ° C.

Methods to check the quality of fire clay

Since chamotte clay is a semi-finished product, it, like all semi-finished products, has its own shelf life. When stored for a long time in a warehouse in conditions of high humidity, if the packaging is damaged, irreversible processes occur in the powder. Three years. the maximum possible shelf life, after which the clay completely loses its properties, and it can be thrown away. Therefore, when buying it is very important to pay attention to the date of manufacture.

Where and how to use chamotte clay

Chamotte clay is used to prepare dry mixes that are used to make heat resistant bricks and prepare mortars for masonry and plastering. Bricks marked with the letter “Sh” are used for laying furnaces and fireplaces.

The rest of the stoves and fireplaces are made of ordinary red bricks. Chamotte bricks are laid with chamotte clay mortar, since they have the same coefficient of expansion. Consumption of the mortar for 100 bricks. three buckets.

Instructions for the use of fire clay

Plastering of the laid stove with chamotte mortar is not much different from the usual. The thickness of the layer should not exceed two millimeters. The mortar should be applied to dry bricks, without wetting the plastered surface. Carefully smooth out the applied plaster layer, and then leave plaster to dry. The time required for drying is indicated on the package of the mixture. Finishing work is possible after a full drying.

By adding certain additives to chamotte, a good plasticity can be achieved. Then this material is used for making tiles, figurines, ceramic dishes, floor VAZ. Drying such products takes a long time, because this process must take place naturally, otherwise the original forms may be disturbed.

How to work properly with fire clay

Chamotte clay in the process of firing kaolin almost completely loses its plasticity, so in order to return the plastic properties, either a special glue or quartz sand is added to the solution based on it. Mortars on the basis of fireclay powder for plaster and masonry are made by different technologies, and in order to obtain the desired result, it is necessary to strictly follow the instructions for use.

Plastering mortar based on fireclay powder

Depending on the area to be plastered, the proportions of ingredients and their amount are chosen. To prepare the mortar, fireclay powder is diluted with normal water. The bag of chamotte is poured into a container designed for the mortar. Small portions of water are poured into the container until the entire mass of clay is completely covered with water.

When adding water, stir the powder mass so that there are no air bubbles in it. After the clay is poured with water, the container is covered with a lid (a sheet of plywood, cardboard), and left to insist for three days. During this time, the clay will turn into a homogeneous mass. The next step is to bring the mixture to the right consistency. If the mixture is liquid, silica sand is gradually added; if the mixture is thick, water is added.

The resulting mixture is thoroughly mixed manually or with a special nozzle for a hand electric drill. The degree of readiness of plaster mortar can be judged by its consistency. it should have the thickness of a good, high-quality sour cream. At this density the mixture will not flow over the surface, and will firmly adhere to it. Some craftsmen add cement at a rate of up to two kilograms per bag of powder to speed up the curing time.

It is recommended to cook the mortar in small quantities, since it hardens within two days. Apply it to the surface to be treated with ordinary spatulas.

Chamotte mortar for laying bricks

To prepare such a solution, chamotte clay is poured into a large. at least ten liters. container, and then diluted with water and sand. The solution is thoroughly mixed, brought to the desired consistency. Properly mixed mortar, if scooped up with a trowel, will not flow or stick, but will simply slide over it, leaving no trace. Masonry irregularities must be completely filled under the weight of the brick.

Pros and cons of fire clay

After deconstructing the features of chamotte clay and some of the subtleties of its application, the consumer will undoubtedly appreciate the advantages and disadvantages of this material. Benefits include:

  • heat resistance;
  • good adhesion to any surfaces;
  • vapor permeability;
  • A long period of defect-free operation;
  • environmental cleanliness.

Disadvantages can be qualified as purely subjective:

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