High Temperature Oven Sealant

Colors

The color of the heat-resistant sealant can be important when it performs its function when sealing the seams of structures that carry an aesthetic load - stove, fireplace, chimney

In other cases, this is not so important. The bulk of sealants, due to the content of iron oxides in them, has a brown-red color

Sealing materials containing sodium silicate are usually gray or black in color. But they can be colored at your own discretion after the polymerization process is completed. Silicone sealants allow a wider range of colors and can be transparent, white or colored.

Types of oven sealants

A through crack that appears in the body of the furnace or the wall of the flue channel leads to depressurization of the combustion chamber or gas duct. As a result, smoke begins to enter the room, the chimney draft decreases, and the overall efficiency of the furnace deteriorates. Of course, cracks can be covered in the old fashioned way with clay mortar, but this will not help for long. It is more convenient and reliable to use high-temperature sealants for ovens for this purpose.

Although dozens of types of similar compositions are offered on the modern market, only 2 of them are suitable for use in furnaces:

• silicone-based (heat-resistant compounds);
• silicate-based (heat-resistant compounds).

As you might guess, in both cases modern polymers come to the aid of stove-makers. The product is a ready-made paste with different characteristics and colors, sold in tubes. In addition, there are two-component heat-resistant sealants. But working with them is more troublesome, it is necessary to accurately dose and mix before use, this will affect the quality of the seal and the service life of the seam.

How to use?

Prepare the work surface before using the sealant. Most sealants adhere well to dry and free from dirt, grease and oil surfaces. If the material is porous, it must be either cleaned or sanded to a solid state, or well primed. It is recommended to first coat the surface of wood with varnish or paint, and after they dry, use a sealant. Metal, glass, ceramics are first degreased with alcohol-containing liquids or acetone. Polymers are best handled with alcohol only.

A sealing material is applied to the prepared surface. To do this, use a cartridge with a special nozzle or a special device in the form of a mounting gun. The sealant is applied to the joint so that the joint is completely closed with a sealing compound. There are special devices that help to align the seam, making it uniform and aesthetically pleasing. Sometimes the sealing compound is applied with a rubber spatula, the width of which is selected depending on the object being processed.

Rules for the use of thermosealants

In the process of active use of fireplaces and stoves, brickwork can crack. The risk of cracks is increased if the brickwork is not tiled, protected by a plaster layer and not covered with heat-resistant paint.

Repair work cannot be postponed - the use of such a fireplace or stove becomes unsafe.

Depressurization of the walls of the furnace section, chimney or other elements of the furnace negatively affects the operational characteristics of the device and entails a number of dangerous consequences.

Possible problems caused by the appearance of through slots:

• fuel consumption increases due to the fact that additional air seeps into the combustion chamber;
• soot appears from the cracks - a corresponding plaque appears on the ceiling, walls; in such a situation, even cleaning the chimney does not solve the problem;
• combustion products that are hazardous to health enter the room - there is a risk of poisoning;
• periodic attenuation of the igniter flame - probably when the chimney is depressurized;
• fuel burns at low temperatures, which is why more soot settles on the walls of the chimney.

Depressurization of the heating system and an abundance of soot are a fire hazardous combination. The incoming oxygen provokes ignition inside the chimney.

With poor-quality thermal insulation of the exhaust duct, the likelihood of fire increases significantly

Most manufacturers sell oven insulating compounds in tubes. Before use, the cylindrical container is installed in a construction gun.

This option is most convenient for filling masonry joints and cracks formed. Sealants are easy to squeeze out of packaging due to their homogeneous and semi-liquid consistency

There are products in soft small tubes. It is advisable to use them for processing small areas. No additional tools are needed to apply the composition.

High-temperature sealants are available in the form of one- or two-component formulations. The first category is most actively used in everyday life.

Two-component compounds are supplied in a set - hardener and paste. The substances are mixed before use in strictly designated proportions.

This option is more often used in industrial conditions when it is necessary to process large areas. In everyday life, two-component mixtures did not take root due to the technological complexity of their use.

The tactics of using silicone and silicate mixtures are similar to each other. However, there are also features that must be kept in mind when sealing furnace equipment.

In addition to the construction tool, you need to prepare for work: a rubber spatula, latex gloves, a brush.

The surface to be treated needs preparation:

• clean and degrease the base;
• it is advisable to process metal elements with sandpaper to improve adhesion;
• wait until the surface is completely dry if water has been used for cleaning.

It is desirable that the thickness of the extruded sealant be slightly less than the width of the joint or crack being processed.

For uniform hardening, the silicone composition must be provided with air access. Therefore, the thickness of the sealant recommended by the manufacturer must not be exceeded.

Full cure time depends on conditions. The package indicates the speed of curing at optimal rates: humidity - 50%, temperature - 23 ° C. In practice, the values ​​vary considerably. The lower the room temperature, the longer the sealant will “set”.

Adhesive tape is necessary to protect the outer coating - the sealant dries quickly, and then it will be problematic to remove it from the base

The surfaces are prepared in the same way as before applying the silicone composition: they are cleaned, degreased, the metal is "sanded" with an abrasive.

Technological nuances of using silicate sealant:

• the porous base must be dedusted and slightly moistened;
• work is carried out only at positive temperatures, optimally above 20 ° C;
• when applying the mixture, adhere to the insulation thickness recommended by the manufacturer;
• excess sealant must be removed immediately, without waiting for the mixture to dry;
• the masking tape is removed after applying the composition.

Some oven sealants require many hours of drying at different temperatures. This information must be specified in the instructions for the product.

How to choose

The choice of a heat-resistant sealing cord for the oven depends primarily on the tasks that need to be performed with it.

Appointment

To avoid unnecessary expenses, you need to take into account the location of the object. After all, it is absolutely not necessary to use an expensive ceramic refractory cord in order to seal a conventional valve on the chimney of a heating stove.

The temperature of combustible gases at the outlet of the furnace rarely rises above 350-400 ℃, and products based on basalt threads can be successfully used.

If the stove is in a bath or in a garage, it would be more expedient to use a cheaper fiberglass or even asbestos seal, since in non-residential premises the impact on the human body will be minimal.

Thickness

Having decided on the type of refractory sealing cord, you need to pay attention to its thickness. The seal itself is quite hard and it will not be possible to crush it strongly in place.

If you take a cord that is too thick to seal the boiler door, for example, after laying it in special grooves, it can prevent it from tightly closing, or you will have to make significant efforts to close the door. This will increase the load on the hinges, locks and fasteners.

Additional processing

Very often, a refractory cord is impregnated with special compounds in order to increase heat resistance. Products processed in this way can withstand very high temperatures. But it is unlikely that such a cord can be required in everyday life or in individual construction, and it makes no sense to overpay a decent amount for it.

It's another matter if you need to use such seals in furnaces participating in production processes at a very high, about 1000 ℃, temperature. In this case, of course, saving is not worth it.

Many manufacturers supply their products with an adhesive layer. This is very convenient for installation, especially the primary one, when the doors, latches, dampers are still new and the seal is easily glued to them. If a cord is purchased to replace an expired one, there is no point in buying products with an adhesive layer. It will take a lot of work to perfectly prepare the surface for gluing. In this case, it is best to buy a regular fire retardant cord and install it using a high temperature sealant.

And, of course, you need to pay attention to the manufacturer of the product. The products of the German brands "Culimeta", "Termic", the Finnish company "SVT" enjoy a good reputation.

Silicone compounds

Once applied and cured, high-temperature silicone forms a hard but flexible layer of material that vaguely resembles rubber. The color of the composition is most often red, this is due to the presence of iron oxide in it. The maximum temperature threshold is on average 250 ºС, some manufacturers declare it at the level of 280-300 ºС.

You will say what exactly such a red substance did you put on the engine parts of a car during repairs, and what does the stove have to do with it? In fact, high temperature silicone sealant for internal combustion engines and furnaces differ from each other in chemical composition. Acid is present in the red substance we are used to, with the help of which the engine parts are sealed. In the open air, it begins to evaporate, giving off a pungent vinegar smell.

Silicone sealants intended for work with ovens are neutral and practically odorless; due to their elasticity, they are resistant to temperature extremes and environmental conditions. The maximum layer thickness depends on the manufacturer and is indicated in the instructions on the package. However, due to the low temperature threshold by thermal engineering standards, the scope of application of heat-resistant sealants is limited to the following types of work:

• sealing cracks in brick chimneys in an area located on the street;
• sealing the junction of the roofing materials to the chimney to prevent water infiltration;
• installation or sealing of chimneys made of any materials, including a sandwich, working in conjunction with highly efficient boilers (efficiency over 90%). The gas temperature in this case does not exceed 150 ºС, this is the normal mode for silicone compounds;
• any work related to filling the cracks (not through!) outside the brick ovens.

Peculiarities

The main active ingredient in the sealant is a polymer material. Depending on the purpose of application, it can be silicone, silicate, rubber, bitumen. The sealant is produced in tubes intended for manual use or using a special feeding device - a mounting gun.

Depending on its composition, heat-resistant sealant is produced in three types - one-, two- or three-component.

One-component sealant is a product that can be used ready-made, and the composition polymerization process takes place at room temperature for several hours. At the same time, it is not required to apply a sealant with a thick layer - a layer with a thickness of 2 to 10 millimeters will quite cope with the task assigned to it. Each manufacturer indicates more specific parameters on the packaging of their products and they may differ for different brands.

• A two-component sealant consists of a base and a catalyst. The polymerization process takes place when these two components interact. The resulting mixture must be used immediately, since it cannot be stored.
• The three-component sealant consists of a main component, a curing compound and a catalyst that accelerates the curing process.

High temperature sealants fall into two categories.

• Heat-resistant sealants can withstand temperature loads within 1300 degrees. The components of such a sealant are capable of contacting with an open flame. The product contains sodium silicate. In turn, heat-resistant sealants are either fire-resistant or fire-resistant. The difference between them lies in temperature conditions and a number of characteristics.
• Heat-resistant sealants can be used in those areas of the structure that do not exceed a temperature of more than 350 degrees in heating. As a rule, these are elements of joints, joints and slots on the outer surfaces of the structure.

According to the composition of the polymeric substance, sealing products are of several types.

• Acidic - sealants that form acetaldehyde during polymerization. This substance can destroy or deform the surface that will react with it. Therefore, acidic sealants can only be used to a limited extent. So, for example, metal surfaces will quickly corrode, while concrete or cement will give powdery oxidation.
• Neutral - a type of sealant that consists of heat-resistant silicone and releases water and ethanol during polymerization. Their use is safe for all types of surfaces, and therefore these sealants have a fairly wide range of uses. The silicone seam is perfectly restored after any deforming effects, and its service life is at least 15 years.

In addition to their distinctive features, all types of heat-resistant sealants share common properties.

• Adhesiveness - the polymer components that make up all heat-resistant sealing products have good adhesion to working surfaces. They can be used on brick, concrete, metal, glass, ceramic, wood or plastic construction.
• Plasticity - the sealing joints after the end of the polymerization time have a certain plasticity. They do not crack, are resistant to vibration and temperature extremes.
• Water resistance - polymer materials are highly resistant to water and steam.
• UV Resistant - Polymer sealants are not susceptible to the damaging properties of UV rays.

According to the scope of application, heat-resistant sealants can be divided into three types.

• for use in construction and installation works;
• used for the repair of motor vehicles;
• narrow-profile special-purpose sealants.

Top manufacturers

It is better to buy products from trusted manufacturers - their quality is usually higher. The low price should be alarming - heat-resistant products cannot be too cheap. Otherwise, organic substances may be added to them to reduce the amount of silicone. The strength of such a material will be much lower, as well as elasticity.

The following brands have proven themselves well:

1. Moment Herment High Temperature. Withstands up to +315 degrees, can be used for car repairs, heating systems, perfectly fills grooves and cracks, is suitable for metal, wood, stone, glass, plastic.
2. ABRO. Sealants of this company are sold in a large assortment, of different colors, with different technical characteristics. Within seconds, the products create gaskets with the highest strength.
3. Penosil. The Estonian brand produces a material for filling seams, cracks, which can withstand up to +1500 degrees of heating.
4. Macroflex. Refractory sealants of this brand are used for joining parts and repairing defects on products with low mobility, since the connection will be rigid. Withstand temperatures + 1200 ... + 1500 degrees.

Soudal, Krass, Titan sealants are also famous for their excellent quality. All these funds can eliminate the need for expensive repairs or rearrangement of stoves and fireplaces. With strict adherence to the instructions, you can get a reliable connection by doing all the work yourself.

Manufacturers

Heat-resistant sealants in Russia can be purchased from both domestic and foreign production. According to analysts, Russian manufacturers have tended to oust foreign suppliers in recent years.

The largest manufacturers of sealants in our country, producing products based on their own developments or foreign technologies, include the following companies:

• Lipetsk company Fenzi - the company produces sealants and adhesives using Italian technology. As an example, one-component sealant "Butilver" can be cited, which operates at temperatures ranging from +120 to + 150 degrees.
• The Bashkir company "Moment" produces sealants using the technology of the German brand Henkel. The products are packaged conveniently for professional and household use. The product called "Moment Herment" is produced on the basis of silicates, the operating parameters for heating reach +315 degrees.

• The Vladimir research and production company "Adhesive" develops and produces adhesives, sealants, elastomeric coatings. An example of this is the one-component sealant "Advaflex", which works in the temperature range up to + 90 degrees.
• The Nizhny Novgorod company "Germast" - the manufacturer develops and produces sealants for various purposes. The Vikar sealant is designed for a wide range of applications, it is produced in the form of a 310 ml cartridge and can withstand temperatures up to +140 degrees.
• The Moscow company "Sazi" is the largest enterprise that specializes in the production of sealing products. The range includes all types of sealants, from household and ending with highly specialized.

• Hobby trademark. The company "Hermetic-Trade" is its distributor in Russia and sells a line of sealants on the Russian market, among which, as an example, we can single out the heat-resistant silicate sealing product "Hobby 1250c" used for fireplaces, stoves and chimneys. The composition of the sealant is capable of working at temperatures up to +1250 degrees.
• Trademark Abro industrials - under this trademark, an American company began to produce in Russia high-quality temperature-resistant sealants in small packaging for use in the installation and construction sector and automobile repairs.

• The Hilti brand produces sealants that are used for joints and joints in structures exposed to high temperatures. The most popular brands are P-301S, СР-606 - the sealing joints of these products withstand deformation well and can be painted on.
• The Penosil trademark belongs to the Estonian company Krimelte. This brand specializes in the production of polyurethane foams, various types of adhesives, sealants and other polymer products. The company's products are quite popular in Russia and are used for professional and domestic needs. An example of a fire-resistant sealant is Penosil Premium Sealant + 1500c - the product is used to seal the seams of chimneys, chimneys, fireplaces, boilers, stoves. It can withstand temperature load up to +1500 degrees.

Main types of high temperature sealants

There are different types of sealants on the market that have the ability to withstand high temperatures. For repairing defects in the oven masonry, it is better to buy those that contain silicates and silicone. The products are packaged in small cylindrical cartridges, which can be conveniently inserted into the assembly (glue) gun.

Also on sale you can find small packages in tubes resembling a paste, which are used like any ordinary glue. Various colors allow you to choose the composition to match the color of the base material to make the patch aesthetically pleasing or even visually invisible. All sealants are divided into heat-resistant, heat-resistant, sealing and facing properties.

Heat resistant sealants

The basis of such funds is silicone, they can withstand up to +350 degrees. To achieve such resistance to heating, iron oxide is also added to the composition, therefore, the main color of the mass becomes orange. Some products contain acetic acid, they are absolutely not suitable for iron - creating an oxide film, sealants will not provide sufficient adhesion. But for aluminum, other non-ferrous metals and stainless steel, they can be used, although for any metal it is better to purchase an acid-free composition.

Typically, heat-resistant sealants are used to apply to the outer walls of fireplaces and stoves. They are also suitable for open areas where the seam will be affected by atmospheric factors, ultraviolet light - for example, for roofing from corrugated board, tiles. You can use compounds to eliminate gaps in the chimney or car parts. The thermal resistance limit is always indicated on the packaging. It must be remembered that +350 degrees is the upper limit of a short-term temperature rise. Constant heating should not exceed + 250 ... + 270 degrees.

Polymerization of the sealant occurs in a few hours, some heat-resistant agents harden only after 1-2 days. The closer the expiration date is, the faster this process takes place. The ideal conditions for the polymerization of the sealant are considered to be + 23 ... + 25 degrees, humidity 50%. Other conditions will slow down or speed up the complete curing of the material.

Heat resistant sealants

Such products contain silicates, therefore they are designed for more serious heating - up to +1500 degreeseven direct exposure to flame is possible. Heat-resistant sealants should be repaired between the bricks, cast-iron elements of the furnace masonry, the seams of the combustion chamber, defects in heating boilers. Sealants do not lose their properties even under extreme heating, but when exposed to open fire, you need to find in the instructions a direct indication from the manufacturer of this possibility.

Heat-resistant sealants are usually black, gray due to the presence of silicates.They adhere perfectly to any materials, and yet it is recommended to sand the surface before applying. The work should be carried out at a temperature close to +20 degrees. After drying, the seam will be tough, since such sealants are not highly elastic. It is better not to use them on products subject to vibration, but they are great for structures that have already undergone shrinkage.

Silicone seals

You can also find a red or blue semi-liquid silicone paste on sale. As it hardens, it forms an elastic seam that can stretch up to 2 times. Such sealants are used for new masonry, which are subject to strong shrinkage. It is also possible to use seals to cover sandwich chimneys from the outside. Means cannot withstand high heating - they work only within the range of -40 ... + 250 degrees. The maximum seam depth should not be more than 6 mm, application is carried out at + 5 ... + 30 degrees. The most popular brands of silicone seals are Titanium, Moment-Herment, Penosil.

Adhesive facing compounds

Materials with adhesive properties are used if the oven masonry is covered with a network of cracks, because it is unrealistic to process the entire area with an ordinary sealant. Facing compounds perfectly penetrate the narrowest and deepest cracks, reliably hiding them. After repairing the fireplace, the stove will acquire a more aesthetic appearance. Typically, such mixtures are sold in buckets ready-made or in bags in the form of a dry powder. The heat resistance of the facing compounds can be different:

• mixtures based on kaolin dust, chamotte - up to +400 degrees;
• one-component adhesives with mineral additives - up to +800 degrees;
• mastics for gluing tiles, stone - up to +1000 degrees.

Consumption

Before proceeding with the work on sealing a particular surface, it is necessary to calculate how much sealant may be required for this. Experts believe that the minimum joint width should be at least 3 millimeters, and in the ideal case, the sealing joint should be within 6 millimeters. The seam depth should always be half its width. Ideally, the seam depth should be less than 3 millimeters. In addition to these parameters, you need to determine the length of the seam. It will depend on the size of the particular object where the sealing material will be laid. Knowing these parameters, we will be able to determine the amount of consumable sealant in running meters.

Manufacturers, in order to simplify this task for us, indicate on their products its volume and the number of running meters that this volume can cover. Many manufacturers on online sites for consumers place special calculators, with which you can determine the required number of units of their products for the given parameters of the coverage area. In addition, manufacturers have a special table, where, depending on the width and depth of the seam, it is indicated for what footage one package of one or another sealant is enough. For example, a cartridge with a volume of 310 milliliters can process 13 running meters of the surface if the seam width is 6 millimeters and the depth is 4 millimeters. And if we take the seam width equal to 12 millimeters, then with the same seam depth equal to 4 millimeters, the cartridge will be enough for us only for 6 running meters.