Refractory masonry mortar for oven masonry

In the construction of fire-hazardous fireplaces and stoves, special solutions are used in the process of lining them. The furnace mixture is selected according to the type and material of the heating structure. Good quality material ensures reliable surface adhesion, has heat-resistant characteristics and is easy to apply. Manufacturers produce finished products that need to be mixed on their own.

Types of mixtures for laying fireplaces and stoves

Fireplace and stove structures are built of natural stone or refractory bricks. To impart solidity to the structure, various compositions are used. They are suitable for outdoor masonry, firebox and chimney construction, foundation pouring, cladding and heat-resistant elements.

By the type of resistance to high temperature and fire exposure, you can choose a masonry oven mixture:

• heat-resistant - retains the integrity and bearing strength of the structure at high temperatures;
• heat-resistant - protects the structural integrity of the masonry when exposed to fire and mechanical force;
• refractory - the property of viscous products that are resistant to fire and combustion products.

The composition and proportions depend on the type of furnace element.

Heat-resistant mixtures

The material is able to withstand heating, maintain the load-bearing capacity of the structure and not deform from high-temperature exposure. A standard mixture for casting a monolithic firebox or erecting a frame is made on the basis of:

• 1 part of Portland cement grade M400-M600;
• 2 pieces of ceramic crushed stone M150;
• 2 parts of fine quartz sand with fractions of 1 mm;
• 3/10 parts of fireclay sand;
• water in the amount of 4 liters per 10 kg of the mixture.

Purchased and self-prepared solutions are mixed in a concrete mixer - all ingredients are added gradually.

Finished materials are cleaned of organic matter, which eliminates the emission of carbon monoxide during the operation of the furnace.

Fireclay compositions

A mixture based on refractory clay and quartz sand, crushed to the state of cereals, is characterized by:

• fire resistance, depending on the manufacturer - from 1550 to 1850 degrees;
• average size of fractions from 2 mm
• moisture absorption - 2-10% for high-burnt chamotte, approximately 25% for low-burnt chamotte.

The fireclay product is supplied in 20 kg bags, which is enough for laying 20-30 bricks. The construction of the chimney and firebox is carried out from a clay-chamotte mixture in a ratio of 1: 1. Water will be needed ¼ part.

On a note! Refractory clay is used for facing work, but only 4 weeks after the first fire of the fireplace.

Dry casting powder

Fire-resistant material based on cement aluminate and chamotte clay with fractions of 0.5 mm is used to fill and repair the internal parts of stoves, grills and fireplaces. It is produced in the form of a gray powder, poured into 25 kg bags. Possesses the following properties:

• permissible minimum pouring temperature - +5 degrees;
• solidification time - for 1 hour;
• output of the finished mass - from 11 to 12 liters from a bag of 25 kg;
• resistance to temperature effects up to +1300 degrees.

The solution is mixed in a concrete mixer. Gradually add 2.5 to 3.5 liters of water to the bag. Large parts of the stove are filled with a layer of 50 mm, the vault - with a layer of 100 mm.

The refractory mass cannot be reinforced - its thermal expansion is less than that of metal.

Characteristics of kiln mixtures

Quality mixtures for stoves and fireplaces must have the following characteristics:

• heating limit from 1300 to 1780 degrees - heat-resistant material does not crack when exposed to high temperatures;
• finished density from 1000 to 1800 kg / m3 - allows you to form a strong layer with high thermal conductivity;
• frost resistance - an indicator of up to 70 freezing and thawing cycles allows for outdoor and indoor construction;
• heat resistance, strength and ductility - properties increase the duration of the furnace;
• environmental friendliness - materials without volatile impurities and chemicals do not emit carbon monoxide gases during the heating process;
• flammability class - refractory product is classified as NG (non-flammable);
• vapor permeability - from 0.09 mg / m * h * Pa - prevents mold from the seam.

A good composition easily adheres to the surface during work, has a plastic structure and ease of application.

Pros and cons

For the laying of stoves and fireplaces, a high-temperature mixture is used, which includes clay, sand, lime or cement, heat-resistant ingredients. To obtain a homogeneous mass, you need to add water to the material. The use of finished products has several advantages:

• ease of mixing components;
• ready-made recipe that ensures the strength of the composition;
• versatility of use - suitable for cladding, masonry, external and internal parts;
• attractiveness and evenness of the masonry seam;
• the presence of a complete instruction with the rules of work and mixing;
• ease of application and absence of risks of destruction of the seam.

The use of building materials is associated with some difficulties. The mass is kneaded only with a mixer or in a concrete mixer, it quickly solidifies, therefore it is prepared in portions.

Selection of mixtures for structural elements of the furnace

To choose masonry materials, it must be borne in mind that the stove consists of several elements:

• The foundation pillow is a monolithic element built separately from the foundation of the house.
• The base of the furnace is not exposed to temperature stress, therefore it is built of red solid brick. Lime or lime-cement mortar is suitable for masonry.
• Fire blind area - represented by a sheet of asbestos or mineral cardboard, on which there is an iron sheet and felt with clay impregnation.
• The massif of the furnace - due to the increased effect of hot flue gas on the structure, is built of ceramic bricks on clay mortar.
• The firebox is very hot, therefore it looks like a monolith on a clay-fireclay mortar of a refractory type.
• The beginning of the chimney - heats up to +400 degrees, which provides for laying on a mixture with a clay base.
  
• An otter, or fluff, is an element that connects the chimney and the ceiling. The temperature and aggressive effect on it is minimal, so a lime composition is suitable for standard bricks.
• Fire-fighting cutting - a heat-insulating metal box for which no mortar is needed.
• Chimney and fluff - exposed to wind, chemicals. They are mounted with a red solution.

The correct choice of solution will save 10-12% of funds for the purchase of consumables.

Lime mixture

Refractory mixture for ovens consists of sand, lime dough (1 part quicklime + 3 parts water). For self-preparation, you will need to sift the sand, mix it with the dough in a 1: 3 ratio and add water until sour cream is thick.

The heat resistance of the product ranges from 450 to 500 degrees, but it is non-hygroscopic. The product is used outdoors to treat the part of the pipe protruding above the roof covering. Due to the toxicity and duration of the fight, lime materials are best used outdoors.

To increase strength, cement can be added to the lime agent, and gypsum can be added to accelerate the adhesion.

Cement mix

They are classified into three types:

• Cement - for preparation requires water, cement and sand. High strength and low gas density allow the use of compounds for the construction of the foundation.
• Cement-clay - strong mortars, with the help of which the thermal part of the fireplace and the beginning of the chimney are laid out.
• Cement-lime - mixtures are strong, but differ in insignificant gas density. Suitable for the construction of fireplaces, foundations, chimneys.

For self-production, you will need to mix 1 portion of cement with 1-3 portions of additives and 6-15 portions of sand.

You can enhance the heat resistance of the cement mass using Portland cement and broken bricks.

Clay mixture

The material is suitable for the construction of a kiln array. Ideal mixture - does not crumble, has a homogeneous structure without lumps and the consistency of sour cream. Factory materials are made on the basis of:

• white clay - increases the fire resistance of the mass, is suitable for the construction of wood-burning stoves with heating the furnace up to 1000 degrees;
• fireclay clay is a versatile product that ensures the strength of the furnace structure at any temperature.

In order to increase the strength, you can add to the solution:

• table salt or sodium chloride - 100-150 g is needed for 1 bucket;
• Portland cement - for 1 bucket, you will need from 500 g to 1 kg of product.

The consumption of the clay mixture per 100 bricks is 25 liters.

Selection of the proportion and checking the solution

The amount of ingredients depends on the location and purpose of the oven structure. To build a structure in a house you will need:

• 1 part sand + 1.5 parts clay;
• 3 parts sand + 1 part lime dough;
• 1 part cement + 8-10 parts sand + 2 parts lime paste;
• a heat-resistant mass for a monolithic furnace is prepared on the basis of 1 part of M400 portland cement, 2 parts of broken brick, 0.3 parts of fireclay sand;
• refractory concrete can be made by mixing 20 kg of the ready-to-use compound with 8 liters of water.

A brick sauna stove is built on the following solutions:

• cement - 1 part of cement + 3 parts of sand;
• limestone - sand with lime is correlated as 2: 1;
• lime-cement - you need 2 parts of lime, 1 part of sand, from 6 to 16 parts of cement.

The firebox is laid out using a clay-chamotte mass. For plastering, asbestos + lime + sand + gypsum, clay + asbestos + sand or clay + cement + sand + asbestos are used.

For outdoor structures, it is better to use a moisture-resistant composition based on 3 parts of sand and 1 part of cement.

Testing the mixture

The quality of the lime dough is checked with a wooden lath. In the process of mixing, the type of mass is determined:

• there is no material on the bar - a lean solution, corrected by adding lime;
• lumps or film remain on the rail - the product is suitable for work;
• a thick, dense layer remains on the board - a fat mass, to which you should add a little sand.

Before using the clay solution, the fat content is tested. You will need to dilute 2 kg of clay with water, mix with a wooden stick and examine it:

• clay adhered to the rail - a greasy product, eroded by sand;
• small pieces adhered to the shoulder blade - you can start laying;
• there is a film left on the bar - the material is skinny, you need to correct it with oily clay.

Salt or plasticizers can be added to adhesion formulations.

Kneading options for oven solution

It is advisable to consider the technology of mixing a solution for a furnace using the example of slurry clay. Stove practitioners use several mixing methods.

Wet option

Clay dissolves in water, the finished mass is brought to the consistency of jelly. The dough is left for several days so that the lumps separate, and the inclusions sink to the bottom of the container. Then the slip with water is poured into another container and defended until completely dissolved. When a clear boundary is visible between clay and water, the liquid is drained.

Dry option

Eliminates time-consuming clay slip. Kneading is carried out by filling a small layer of clay into a trough with small sides. Dry sand is poured over the material. The components are mixed with a hoe - they do "chopping" or "weeding" in 5-6 approaches until large lumps are completely crushed. To prepare the solution, you will need to add water in small portions.

Mixing times can be shortened with an electric clay mixer. It is used only on medium fat, low fat and medium soluble types of clay.

Application features

In the case of self-preparation of the solution, several rules must be taken into account:

• For the construction of the kiln massif it is worth increasing the heat resistance of the material.
• With a joint thickness of 3 mm, 25 kg of mortar is needed for every 90 bricks.
• Fatty grades of clay, after drying, lose their strength and crack.
• In order to increase the strength of medium-fat clay, cement can be added to the mass.
• You can speed up the drying of the masonry by adding lime to the solution.
• The volume of the building material is checked after the final batch.
• For each day of work, a new portion of the mixture is prepared.

When working with ready-made products, they are guided by the manufacturer's recommendations. The materials are accompanied by instructions with specific tips for use:

1. Water is added to the contents of the bag.
2. The ingredients are mixed with a drill with a mixer attachment per 1 hour of use.
3. After hardening, they do not work again with the mixture.
4. The laying of the heating structure is carried out at a temperature of +10 degrees.
5. To prevent cracking of the seam, it is necessary to purchase materials with plasticizers.
6. The first heating is not performed for 3 days after laying.
7. The cladding is performed 20-30 days after the oven is put into operation.
8. Efflorescence on the seam is removed with a damp cloth.

The effectiveness of ready-made solutions is better than homemade ones, but they are more expensive. For this reason, it is worth exploring the products of different brands.

Manufacturers of ready-made kiln solutions

Russian consumers can purchase compositions of domestic and foreign production. There are heat-resistant, fire-resistant and standard masonry materials on the market.

Plitonit

Domestic brand that produces furnace solutions according to German technologies. Popular products include:

• Thermal lining. An economical tool for repairing and masonry of external parts of fireplaces and stoves;
• Refractory. A mixture with reinforcing components, used for the construction of a combustion chamber made of heat-resistant bricks;
• Hot melt glue. The adhesive on which the ceramic tiles sit. The glue is also used as plaster.

The proportions for mixing are indicated in the instructions, depending on the type of composition.

Stove-maker

Refractory mix for masonry The stove is made on the basis of clay and cement ingredients. It has a high water-repellency, ensures the strength of the hitch.The peculiarity of the stove-masonry mixture is that heat-resistant products can withstand heating up to +1350 degrees. The advantages of the material include heat resistance, ease of use and reliability of the seam. The disadvantages are the high consumption due to the quick adhesion.

Bossnab

Russian products based on red clay and quartz sand make it possible to mask the seam. The mixtures are produced by Nevsky Terminal SPb in two series:

• Budget. Inexpensive formulations in the form of a mix of red clay and sand. The materials are suitable for interior work and are characterized by low consumption - 25 kg is enough for 90 bricks;
• Premium. They are characterized by resistance to temperature fluctuations. Plasticizers and lignosulfates in the composition allow for outdoor laying.

Low-cost solutions are characterized by heat resistance of +500 degrees, premium solutions - at +1100 degrees.

Terracotta

Heat-resistant products are made of kaolin clay, chamotte and sand, and are environmentally friendly. A plastic solution allows you to form a strong seam that can withstand heating up to 1300 degrees. The masonry line is uniform, the composition is easy to apply. The manufacturer recommends sieving the material to remove large grains of sand and working with soaked bricks.

When building a furnace yourself, you need to choose the right materials. Ready-made factory mixes eliminate the time spent preparing the solution and preparing the ingredients.