home Electrics

When can you light the stove after filling it with clay? How to coat a stove so it doesn't crack from the heat. Other ways to get rid of cracks

The need to seal the stove appears when cracks form in the seams and bricks, causing smoke to enter the living space rather than exit through the chimney. To save money, it is better not to call a specialist, but to do the finishing yourself. The procedure does not require special skills and will not take much time.

How to cover cracks in a brick stove?

Smoke may not escape through the chimney due to soot accumulation or if the stove has not been used for a long period. Cleaning and warming up will help improve heating in the house. If the problem persists, the cracks should be covered.

One of the reasons for smoke entering a living space may be cracks that appear, which are formed for the following reasons:

poor quality solution;
improper finishing;
gross violation of the technique of use;
uneven heating of the structure;
drying of materials.

If the problem is an incorrectly made foundation, then drastic measures may be required, including disassembling the furnace. However, with minor cracks, you can simply coat the stove, after first removing the lining and plaster from the bricks. The best options for putty are clay mixed with sand, glue and grout. Materials should be selected based on the extent of damage and financial capabilities.

Raw materials for embedding

Clay and sand

Ordinary clay is suitable for filling the defect.

The advantages of such materials are low cost and reliability, which is not inferior to more expensive modern raw materials. To prepare and apply the solution you will need the following:

plastic or iron container;
construction sieve (holes from 3 to 5 mm);
bucket;
shovel;
clay with a minimum amount of impurities;
sifted sand.

The homogeneous mixture should be oily and plastic. To avoid the formation of new damage in the future, it is recommended to dilute 300 g of ordinary salt in every 10 liters of solution. The mixture itself is prepared in the following order:

The clay is soaked during the day in warm water, and then thoroughly kneaded to avoid the formation of lumps.
Clean sand is added to the container in a ratio of 4:2, as well as water so that the mixture has a consistency similar to sour cream. Additionally, you can add lime, which will prevent the bricks from turning white.
The container is covered with polyethylene film for 1 day.
The mixture is kneaded again. At optimal viscosity, a ball rolled from the mixture will not crack when pressed. If cracks appear, more water must be added.
Before covering the cracks, the stove should be heated and the damage should be washed with water.

Sealing adhesive

To prevent the defect from reoccurring, you will need glue with heat-resistant properties.

Ready-made material, sold in construction stores, is used to prevent the stove from cracking again in the future. Not any glue will do, but only heat-resistant glue, which has high resistance to elevated temperatures and a long service life. The material consists of fireclay powder and refractory cement. As a putty for cracks, plastic glue is most effective, and if plastering is necessary, a solid form is suitable for the entire stove.

Do not mix the mixture in large quantities, as it will dry out quickly.

Special grout

Construction stores offer putty mixtures with different compositions, which are optimal for lining brick stoves and fireplaces. However, they have a high cost. If financial resources are limited, you can prepare the grout at home. The following preparation scheme is used:

The clay is kneaded, filled with warm water and left for 10-12 hours.
Sand is carefully introduced in a ratio of 4 to 1.
For every 10 kg of clay, an additional 50 kg of straw and 500 g of table salt are added. After which the mixture is thoroughly mixed.

Sealing with fireclay clay

If the stove is very old, then fireclay clay may be the best option for repairing defects.

The solution is recommended to be used if it is necessary to restore an old brick oven. The advantages of fireclay clay are its low cost, fire resistance and long-lasting effect. Construction stores sell the material packaged in 20 kg bags. The mixture is easily prepared according to the instructions included with the building material.

The channel at the stove is clogged, I pulled out the bricks, cleaned it and sealed it with a fireproof Hermes mixture, but the problem is that it is cold in the house, and all the seams after heating were cracked from the temperature difference, how can I seal the seams at the stove?

The reason for the appearance of cracks in the stove array, as a rule, is not the cold in the room, but the CTE (coefficient of thermal expansion). More precisely, the difference in CTE for different materials.

Most likely, your stove is made of red ceramic brick. And the fireproof mixture “Hermes” is made on the basis of fireclay clay. And it is used as a masonry mortar for fireclay refractory bricks (marked ШБ). Fireclay brick has a higher CTE, and therefore an attempt to use fireclay mixture for laying red brick is doomed to failure in advance.

In general, in an ideal world, the best clay for laying brick kilns is the one from which the brick is made. But this is rarely achievable, and therefore they simply try to use fireclay mixtures for fireclay materials, and red clays for solid ceramic bricks.

Here we can advise you to look for masonry stove mixtures based on red clay (these are found on sale, although less often than fireclay fireproof ones), or prepare a solution yourself from red clay and sand. How to prepare masonry mortar can be found in almost any book on the stove business. A good and accurate way to determine the fat content of a solution is in this book:

Useful book for the home handyman

The second probable reason for cracking of seams during stove repairs is shrinkage of the clay mortar.

When clay gets wet, it swells and increases in volume. When drying, it shrinks. The magnitude of these fluctuations is very significant and can reach 13%. By introducing leaning additives into the solution, this value can be reduced to 6%. But it will never be possible to reduce it to nothing.

Accordingly, when you seal a crack in a dry oven, the solution dries and contracts by 6% of its volume. This leads to the formation of cracks. Nevertheless, there is a solution - to introduce additional reinforcing elements into the repair solution. Create something like a clay composite. Most often, sheet asbestos is used for these purposes - it is safe in clay.

How to properly repair a crack in a stove:

Prepare a clay solution. If there is a crack in the masonry of fireclay bricks (Sha-8, Sha-6, Sha-4, etc.), then fireclay refractory mixtures are used. The detergent is fireclay grain. If the brick is red ceramic, use mixtures based on red clay. The remover is sand.
Add table salt to the solution. It will give your patch strength and help it adhere to the masonry, improving the adhesion of the mortar. Approximately a pack weighing 1 kg per bucket of 12 liters of solution.
Soak sheet asbestos in the input. After about 10 - 15 minutes it will disintegrate into a mush that resembles ground cellulose. This porridge should be added to the solution - it will play the role of a plasticizer and reinforcement. There is no need to get carried away. There are about two liters of this asbestos porridge per bucket of solution.
Seal cracks or seams. After first cleaning the surface to be sealed from dirt and thoroughly moistening it with water.
If the stove is cold (it’s better to seal it on a hot stove), then they carefully begin to heat it as soon as the damage is repaired. If necessary, any defects that appear in the seal are lubricated until the repaired area dries and stops cracking.

That, in fact, is the entire fairly universal method of repairing furnaces.

Any stove, even one made according to all the rules and traditions, can crack over time. This is due to various circumstances, but most often due to uneven heating. People who laid it out themselves or used low-quality materials are often interested in how and what to cover the stove so that it does not crack. Regardless of the reasons for the appearance of cracks and cracks, their presence poses a serious threat to the life and health of the inhabitants, since carbon monoxide enters the room through them. In this article we will figure out how to cover or plaster the stove to prevent it from cracking, and what materials to use for this.

How to cover up cracks

It is important not just to “cover up” them, but to examine them in time and seal them correctly to prevent the ingress of carbon monoxide. If you use low-quality material again, instead of one crack, several will appear and quickly.

So, the entire process of removing defects can be divided into 3 stages:

analysis of the crack and the nature of its origin;
preparation of solution;
plastering and grouting.

Crack Analysis

Even a beginner can handle this stage. The task is to determine the location and size. In case of minor damage, as a rule, not through and therefore not dangerous, you can simply clean the bricks from the previously applied finishing and part of the mortar in the area of the crack. Seal them with the prepared solution and clean them so that the restoration work is not noticeable.

If we are talking about deep cracks, especially those through which smoke and a characteristic odor noticeably leaks, you will have to dismantle the bricks in this area and re-lay new ones. This is a painstaking job that requires the correct selection of solution and careful work.

Preparation of the solution

Regardless of the location and size of the cracks, a certain solution will be needed to eliminate them. These can be traditional materials - fireclay clay or a mixture based on river sand and clay, modern - stove glue, personally prepared - stove grout. By the way, you can also purchase it at a hardware store and dilute it yourself.

The table below shows examples of components for plastering stoves and their proportions.

Each material can be used in the work, but in order to understand how to plaster the stove so as not to crack, you need to understand each of them.

The most popular material for laying stoves and fireplaces, restoration and plastering. Fireclay clay is the most reliable material that has passed centuries of testing and is still very popular. The stoves, built on fireclay clay more than 100 years ago, still stand and do not crack.

Today you can buy fireclay clay at any hardware store. Standard packaging is 20 kg, but there are also individual packages of 5-10 kg or large batches of 50 kg. Before work, according to the instructions, the clay is soaked in water in a ratio of 2:1 and left for a day, after which they proceed directly to the plaster.

Clay and sand

The cheapest option for plastering the stove not only during the restoration of cracks, but also during the initial laying. Despite the fact that such material costs a penny, it is very flexible, easy to work with, and after the first two starts of the furnace it becomes very strong and durable.

How to cook:

Pour 1 part clay with 3 parts water and leave for 72 hours.
After one and a half days, stir the solution thoroughly, adding a little water, and strain it through a medium sieve (mesh cross-section up to 3 mm).
Drain off excess water, then mix well again. The result should be a creamy “product” that is ready for the addition of sand.
At this stage it is very important not to overdo it with sand. Add it gradually, continuing to stir the clay solution. Periodically remove the stick and check how much is stuck to it. As a result, there should be small fragments on the stick. If large pieces stick, continue mixing the solution with river sand. As a rule, the ratio is 1:2.5, where 1 part is clay, the rest is sand.

In order to avoid mistakes, watch the video on how to properly prepare clay for grouting cracks

Procedure:

thoroughly mix the composition obtained for restoration;
To check how plastic and high-quality the mixture is, simply make a ball of clay, roll it out and squeeze it tightly with your fingers. The ideal composition will be like hard plasticine, wrinkled, but not cracked. If cracks appear, you will have to add a little more water;
Moisten cracks and crevices generously with water;
push the solution with your fingers, trying to get as deep as possible;
sand the seams and proceed to general plastering.

Oven grout

Of course, it is best to purchase ready-made grout, which is simply diluted with water. It is expensive, but it is ideal for ovens. Very plastic, strong, durable, capable of maintaining integrity even at 1000 0 C.

Before sealing the cracks with a special grout, they are pre-moistened with water immediately before application.

For those who do not have the opportunity to purchase grout, we will tell you how to prepare a composition identical in characteristics to the grout.

You will need:

clay - 1 part;
water - 3 parts;
sand - 4 parts;
straw, cut into small pieces - 1 part;
salt - pack.

Mix clay with water in a ratio of 1:3 and leave for 2-3 days. Next, add sand and gradually knead (see above for how to do this correctly). When finished, add straw and a pack of regular table salt.

Furnace glue

Very comfortable and practical material. which is also sold in all hardware stores. Its main advantage is ease of preparation and simple application.

There are 2 types of oven glue - plastic and hard. Plastic is used to seal cracks, while hard is a finishing coating that hardens very quickly.

The oven glue hardens within 15-20 minutes. To avoid wasting it, knead in small portions.

The procedure is as follows:

preparing 1 liter of plastic solution;
abundant wetting of bricks with water;
applying (pushing) the mixture into all detected cracks and crevices;
preparing 5 liters of solid solution;
coating the entire oven.

Cracks appear on any stove. In the video you will see how to seal cracks and crevices on a Russian stove with a stove bench

How to plaster a stove so it doesn't crack

The first step is always to seal the cracks and, after they have dried, they begin to cover the entire surface of the stove.

With any restoration method, it is necessary to remove the layer of plaster on the bricks/bricks at the site of damage, the cladding or the decorative layer.

Always before filling cracks with mortar, moisten them generously with water - this will form an excellent bond between brick and mortar, so that it will not fall out as it dries.

Cracks and cracks are sealed only with your fingers so that the solution penetrates deeply. Buy waterproof gloves.

Once all damage has been repaired, leave the oven for at least a week to allow everything to dry completely. And after that you can melt it completely - no more cracks will appear in this place.

Even the most durable stove can crack over time. If you ignore the need for repairs, the heat source will not last long. The question is: how to cover a stove - brick or metal? The article discusses the causes of cracks and how to eliminate them.

Figure 1. Cracks in the furnace

Why do cracks appear in furnaces?

Most often, problems appear in brick fires. There are 4 main reasons for violating the integrity of the masonry:

prolonged absence of heating in the house; if the stove stood in an unheated building during the winter, then cracks cannot be avoided - and not only in this structure, but also in the walls of the building;
ignoring operating rules; a “fresh” stove must stand – the masonry mixture should set and the structure should dry well; heating a damp hearth will certainly lead to the appearance of cracks;
uneven heating of furnace zones; the structure must be made in such a way that heat is distributed evenly throughout it; otherwise, the thermal contrast boundary line will become clearly visible - the masonry will crack in this area;
difference in thermal expansion coefficients of masonry mixture and masonry; the furnace material and the solution must have approximately the same thermal expansion rates, otherwise the surface will be covered with a network of microcracks; This is not the biggest problem - cracks are not visible on a cold structure.

Figure 2. Gaps formed along masonry joints

These four reasons lead to troubles that can be relatively easily eliminated with putty. But there are more fundamental reasons:

improper foundation design; if the latter, for example, does not correspond to the dimensions of the heat source, the stove monolith will be damaged; the oven will begin to crack even if the shrinkage of the base does not go according to plan;
incorrect calculation of physical characteristics of materials; for example, without a reserve in thermal seams, the metal structure will “break.”

In these two cases, putty will not help. We'll have to move the oven. Therefore, the first step is to diagnose the structure. Once you are sure that the problem can be solved with little effort, you can proceed to the next steps.

Important! Before repairing, you need to make sure that restoration can be done. There is no point in sealing cracks if the cause is fundamental

How to cover up cracks?

You can cover the stove with a purchased mixture or a solution you prepare yourself. Further about the features of the options.

Sand-clay mixture

Putty made of clay and sand is the most accessible and inexpensive option. Scheme for preparing the mixture:

you need to take clay and fill it with water in a ratio of 1:3; after this you need to leave the mixture for at least a day;
The clay should be thoroughly mixed, adding liquid from time to time; after kneading, strain with a fine-mesh sieve and tincture again (several hours);
after the next infusion, you need to drain the water and make sure that the mass has a creamy consistency;
you need to mix clay and sand - first in equal proportions.

Readiness is determined using an object used to mix the solution. If too much clay sticks to it, add a little sand. As a result, the ratio of components can be from 1:1 to 1:2.5. The composition can be considered ready when a small amount of the viscous component remains on the stick.

This recipe is approximate as clays can vary greatly. It is best to rely not on a stick with stuck clay, but on the result of experiments. Experienced craftsmen make grout with different compositions. After this, several different types of cakes are dried in a place free from sun and wind. Those pieces that are not cracked are dropped from a meter height. “Surviving” flatbreads demonstrate the optimal ratio of components.

Read also: review and preparation of material.

Fireclay putty

Figure 3. Bag of fireclay clay

A slightly more expensive, but also more effective option. Fireclay clay is very heat-resistant and durable. Most often, fireclay is used for stove repairs. The material is sold by construction stores. Before sealing the structure, purchased clay is infused in water for a couple of days.

Oven adhesive

If you need the best option, use a special mixture for ovens. The solution consists of fire-resistant cement and fireclay powder. There are two main types of glue you can buy in supermarkets - viscous and hard. If you are looking for something to cover up small cracks on the stove, purchase the first type. Solid mixtures are used for plastering.

The main advantage of factory materials is the optimal ratio of components and very thorough mixing. It is impossible to achieve such quality at home. In addition, there is no need to waste time preparing grout. Another advantage of ready-made compositions is quick setting.

An alternative option is oven grout.

Factory solutions are good for everyone, except for the price. There is another opportunity to save money - use putty prepared according to the following recipe:

the clay is broken into small lumps and infused in water for about 12 hours;
sand is added to the mixture of water and clay, after which the components are thoroughly mixed;
during the mixing process, crushed straw is added to the composition from time to time, which reinforces the solution;
After the mixture becomes homogeneous, salt is added to it (about a pack).

The ratio of sand and clay is 1:4. You need about 10-15 kg of straw per bucket of clay. It is easy to see that this is a modified version of the sand-clay mixture described above.

How to cover up cracks and plaster a stove?

Figure 4. Plaster over reinforcing mesh

To prevent the stove from cracking, you need to take a competent approach to its construction and operation. But if cracks do appear, they need to be eliminated as quickly as possible. Regardless of the type of mixture, the structure should be prepared before restoration. The surface is cleaned of dirt and debris, and the cracks are deepened and widened. If there are bumps and sagging on the base, they are knocked down.

Remember! If the oven begins to crack due to insufficient shrinkage, you need to let it sit completely. Otherwise, after repairs, the structure will again become covered with cracks.

Before coating, the hearth must be heated. Due to the high temperature, the furnace materials will increase in volume. This will avoid repeated cracking immediately after post-restoration heating.

If there are few “seams”, they are sealed locally before plastering. Otherwise, a complete coating is used - the entire surface is covered with liquid heat-resistant putty.

Scheme of work

Figure 5. Local filling of cracks

In general, the procedure is as follows:

clean the base and perform other additional work;
cover the surface with a thin layer of liquid mixture and allow the putty to dry;
reinforce the base (or cracks, if the repair is local); for this purpose, a metal mesh with small meshes is used; fasten the reinforcement with nails or dowels; as an alternative to the mesh, you can use burlap soaked in putty; It is preferable to use it to seal cracks pointwise;
after the starting layer has dried, the fireplace is plastered; the oven is coated in two layers - the thickness of each layer is no more than 5 mm.

The next steps are at the discretion of the stove owner. The structure is covered with whitewash or decorated in another way.

How to eliminate cracks in a metal structure?

The main solution to the problems of cracks in metal stoves is obvious - welding is used. But if this option is not suitable, you can use special fire-resistant putties.

Recipes for preparing mixtures are presented in the tables.

Table 1. Ratio of water-based mixture components

Table 2. Ratio of components of a mixture based on natural drying oil

Conclusion

To prevent the stove from causing trouble, you need to think about possible problems already at the design planning stage. But if the heat source does crack, in most cases it can be fixed with caulking and plastering. And only if this does not help, the oven will have to be disassembled and rearranged.

After a long winter, many go to the dacha for the first time this season and, getting ready to relax, light the stove in the house or in the bathhouse. And they are very surprised when they feel carbon monoxide entering the air in the room - after all, nothing like this happened last year. After a preliminary inspection, they are convinced that smoke has penetrated through the cracks that have appeared and immediately think about how to cover up the cracks on the stove.

After calling the stove maker, it turns out that there are many problems with the structure and it requires major repairs. Without telling you how to coat the stove, he immediately issues an impressive bill, which not everyone can afford to pay. In this article we will talk about the rules for troubleshooting problems of this kind, that is, we will figure out how to cover the stove so that it does not crack.

There may be several reasons for smoke in a house or bathhouse. If you see a small crack, this does not mean that carbon monoxide is coming through it; it may not be through. Therefore, you first need to correctly determine the cause of the smoke and only after that you can start thinking about how to cover up the stove.

The first option may be to clog the smoke duct with soot. If such a problem is detected, you should simply.
In the second option, cracks may appear in the chimney or the stove itself. In this case, the air supply through the ash pan decreases, the temperature of the exhaust gases decreases, and the combustion process worsens.
Smoke may occur due to improper internal masonry, or the riser itself may be clogged with brick waste. Such a malfunction can only be corrected by cleaning, or the entire chimney must be restored.
Leaving the stove for a long time can also lead to smoke. The riser itself becomes overcooled. But this malfunction can be easily eliminated: before kindling, you just need to burn a little paper, placing it in the cleaning door, and the channel will begin to work in the desired mode.

Repairing cracks

When laying and plastering a stove, it is almost impossible to ensure that the surface does not crack; cracks can occur in any equipment intended for heating. Almost anyone can eliminate this deficiency. You just need to come to the store and ask the seller what to cover the stove with. Trade workers will offer many types of putty to eliminate cracks in metal, but don’t get your hopes up too much, since a crack in metal can only be welded - any putty can only help for a very short time.

Spider web cracks

Many people observed that the plastered surface of the stove was cracking, forming a web of small cracks located close to each other. These are small, non-through cracks that spoil the appearance of the structure. You can and should get rid of them, as the shedding of the plaster will only increase. The surface of the plaster cracked as a result of the solution being prepared incorrectly. How can this defect be corrected? The work order is as follows:

Clean the surface. Use a chisel to knock out the cracks.

Attention: do not knock out one crack at a time. Completely clear the area of formation. Moreover, cleaning should be done to the hard surface of the brick. If you don't do this right away, the cracks will reappear.

Clean the hard surface with a metal brush.
Moisten the surface thoroughly with primer. To do this, you can simply mix cement with water and bring the solution to a liquid state. Lubricate the cleaned area with the resulting solution using any brush.

After breaking up the cracks, we get planes that need to be plastered again. The surface is primed and dry. At this time, you need to prepare the correct solution for the plaster. Plastering a stove in a bathhouse or in a house should be done with a clay solution. For the correct proportion of clay and sand, the fat content of the clay should be determined, this can be done like this:

We make five test samples of clay mortar. We mix clay with sand in different proportions.
Sift the resulting mixtures through sieve with a cell of 1.5 mm.
Add water and bring it to a plasticine state.
Making balls diameter 5 mm and drop them from a height of 1 m onto a hard surface. The one that won't break will have the right ratio of sand to clay.

After determining, we knead in the required quantity and begin plastering the area where we cleaned. The area was treated with primer. If it is completely dry, it should be moistened with a spray bottle to keep it moist.

Using a trowel, apply the clay mixture to the wall of the oven. Use the spraying method (the solution in small parts is simply thrown onto the wall and sticks).
Using a large wooden grater, level the surface, while lightly pressing the tool.
We are waiting for the mixture to dry.
We fill cracks and depressions with clay mortar using a triangular trowel. If the finishing area falls on a corner, we apply a wooden plank to this place and use it as a limiter.
We take a wooden grater and treat the surface with it. We wet and rub in a circular motion, pressing the tool slightly.
Let the surface dry.
Using a metal trowel, spray the final layer of mortar, moving from bottom to top.
Let it dry and use a wooden grater, previously soaked in water, to rub it in a circular motion until the unevenness completely disappears.

Other types of cracks

If, then small cracks are rubbed with a solution of alabaster and chalk. Elements of the tile that have received defects as a result of heating are simply replaced with others. In this case, a clay solution is used. Before installing a new element, the mounting area should be thoroughly cleaned of old mortar and moistened. Sometimes cracks are formed due to loosening of furnace devices (doors, valves, etc.). In this case, you should remove the door from the masonry. The mounting area is completely cleaned.

A hole is made in the masonry for fasteners (wire).
A wire is attached to the door frame, and the frame is wrapped around the perimeter with asbestos cord.
After this, a clay solution is applied (the preparation process is described earlier).
The door is firmly inserted into place and secured with wire.

Sometimes cracks form in the masonry of the firebox or the first chimney channels; the brick simply remains loose in the structure. This brick needs to be moved:

To fix the problem, you should select a high-quality brick. The temperature is highest here. In other places where brick is replaced, a material of lesser quality will be suitable.
The walls of the brick must be smooth. Inside the channels, friction of gases occurs against the walls of the chimney surface, so they must be as smooth as possible.
Having pulled out the brick, we clean the surface of the old mortar using a metal brush.
Place the clay solution on the cleaned surface.
We lay the prepared brick in place of the fastener. As a rule, the internal brick is attached to the mortar on all sides. More mortar should be placed on the bottom of the brick stack so that when a replacement is inserted, by pushing the brick in, a mound of mortar is formed on its back surface and when pressed, all cavities are filled.
If cutting of bricks is required during the work, we lay it so that the smooth surface is directed towards the exhaust gas outlet. These surfaces cannot be rubbed down; the clay will dry out and crumble, which will clog the channel.

Sequence of correct furnace firing

before kindling, you should always clean the ash pan, put dry wood chips on the grate, close the ash pit and set fire to the food;
place firewood in the firebox and open the vent completely, this warm air will break through the stagnant air in the pipe and adjust the operation of the chimney; the second load of firewood should be made when the first one burns down to the state of large coals;
do not fire with peat, and especially with coal in a furnace, the solution of which is made without the addition of fireclay powder: the usual mixture can only withstand the burning temperature of firewood; under the coal, fireclay powder is added to the batch, which increases the heat resistance of the structure;
coal combustion is not carried out on grates made of metal and metal furnaces: metal burns out extremely quickly from the high temperature of the coal;
Load the corner after the oven has warmed up strongly.

Attention: if you call a stove-maker who does not ask what the stove is heated with, this should raise concerns about his competence. Remember: when using peat and coal briquettes in the firing process, repairing masonry and sealing cracks in the furnace are carried out only with the addition of fireclay powder.

Repairing cracks in metal furnaces

Sometimes cracks occur in metal structures. And here you shouldn’t think about how to coat the stove; only welding will help in this matter. As a rule, they appear after improper use of the structure, which is also affected by rapid loading of solid fuel. But this problem can be fixed:

We prepare the crack. If it is small, you need to make holes along the edges of the crack, but in metal that has not yet been fractured. This is done using a drill with a drill bit that is twice as large as the crack itself.
After preparation, we perform welding with a welding machine. We make a wave welding seam.
After welding, we clean the seam with a grinder.
If the crack is large enough ( width more than 5 mm), you should cut it out with a grinder, make a metal patch according to the thickness of the oven wall and weld it.

Attention: if the stove has just been laid, and the next season cracks already form in the masonry and several bricks fall out in one place, do not try to repair it, it will be wasted money. In this case, most likely, the channel was laid out incorrectly or poor-quality material was used during installation. If you do not completely redo this section of the structure, you will pay for cosmetic repairs every year.

When installing the stove, monitor the quality of the material and the correctness of the work. This will help you avoid cracks and breakages.