When heating systems fail, it is not safe to use them. It is impossible to dismantle some structures and install new ones for a number of reasons, and it is impractical to make new laying of furnaces. Therefore, it is easier to restore the integrity of the destroyed elements and repair cracks and seams.
Heat-resistant compounds will come to the rescue. The real discovery was the emergence of high temperature sealants. With their help, you can not only carry out repair work, but also install new systems.
Features and Benefits
A feature of any heat-resistant sealant is its ability to perform its functions at high temperatures. Its purpose is to fill, record and connect. With all the variety of types and brands of this product, their main advantages over conventional sealants are obvious. The component composition of thermosealants includes a special polymer-based substance that characterizes the specificity of their application.
It is a high molecular weight substance with a complex chemical formula that provides adhesion of surface molecules and sealant. These or those features of sealants depend on the varieties presented in the consumer market. All of them are mainly produced in special tubes of various sizes and qualities. The format of their use can be different: from manual to application with a pistol.
One of the leading places is occupied by hybrid mixtures. In addition to high levels of reliability and strength, these new generation sealants are resistant to ultraviolet rays, chemical compounds and high temperatures. Hybrid sealants retain their inert properties for a long time, which significantly increases their shelf life. They are simple and convenient to use. Possessing a good binding structure, they perfectly cope with their functions when exposed to high temperatures. The good extrudability of these formulations allows for a wide temperature and geographic range of application.
MS polymers are safe and environmentally friendly to use, practically do not emit pungent chemical acetate odors. Due to the absence of solvent elements in the composition, they are safe for the environment and humans. Hybrid sealants have very good cure properties. They are moisture resistant. Among their advantages is the ability to paint with various colors, any paints, even on a still wet surface, without any effect on the hardening of the layer. However, in terms of heat resistance, their performance does not exceed +120 degrees Celsius.
To eliminate chimney leaks, as well as to protect stoves from cracking, where special sealing compounds are required, special heat-resistant fire retardants are used. Their classification is based on the degree of heating of the elements.
Heat-resistant sealants are used when surfaces do not heat up above +360 degrees Celsius. They fill the seams in brick and masonry, seal the joints of structures. The waterproof components of the sealant provide protection from the weather.
Heat-resistant mixtures are intended for surface areas with a temperature maximum of up to +1500 degrees. They are used in the processing of masonry joints with fire, in the chambers of furnaces and fireplaces, on high-temperature pipes and other structural elements.
Modern formulations contain additives that affect heat resistance. For the treatment of the chimney, a sealant containing iron oxide is used, which significantly increases the temperature range of its use. There are also types of copper sealants. Iron and copper endow the sealants with special strength properties. The shelf life of oven sealants is quite long and, subject to the conditions stated by the manufacturer, is 15 years. Some of them are capable of withstanding up to +4000 degrees Celsius.
Each species, along with positive qualities, has its own characteristics. So, a sealed silicone composition for metal, with all its advantages, including water resistance and immunity to temperature extremes, has low vulcanization and cannot be stained.
Surfaces treated with silicate sealants become resistant to extreme high temperatures. They are strong and paintable, but have poor adhesion to some smooth surfaces.
All sealants in this series comply with fire safety standards. It is important to properly implement operating conditions and follow label directions.
Types and characteristics
High temperature sealants are designed for temperature ranges of +200 - + 300 degrees Celsius. They are suitable for sealing cracks and joints in chimneys and heating systems. The resistance of sealants to high temperatures depends on the polymer range used in their manufacture. On this basis of the polymer base, they are divided into silicone, silicate and bituminous.
The purpose of the sealants can be changed in accordance with the specified characteristics. Bituminous sealants, due to their inability to withstand high temperatures, are used to a limited extent. High-temperature sealants are divided into two groups: heat-resistant and heat-resistant. They are different in their properties and degree of resistance to temperature influences. Heat-resistant ones are capable of heating up to +1500, and heat-resistant ones - up to +300 degrees Celsius.
The temperature-resistant silicone sealant contains synthetic rubber, which significantly expands its scope and allows it to be used in outdoor work. Silicone sealants are also used as adhesives for bonding ceramics, glass, wood and other surfaces.
According to their composition, silicone sealants are divided into one-component and two-component
As the name suggests, heat resistant one-component sealants are ready-to-use without any additional preparation. At room temperature, the composition sets immediately. When hardened, the sealants provide good adhesion to the surface, which completely eliminates reapplication of the layer. The thickness of the sealed compound is from 2 to 12 millimeters.
Two-component sealant is a rare occurrence. It is made of two parts: a polymer base and a catalyst. When combined, the elements enter into a chemical reaction and the composition hardens. In terms of functionality, it is in no way inferior to its one-component analogue, but in terms of the method of application it has some difficulties: it must be fully used immediately after preparation. It retains its properties for several hours, and then hardens and deteriorates.
According to the composition and method of application, heat-resistant sealants are divided into types. The most common of them are thiokol, paste sealants, gasket sealants, silicone, silicate (oven), adhesive sealants and hybrid. Each type of sealant has special characteristics and a number of advantages.
Thiokol high temperature sealant is one of the most durable oligomer-based sealants. It is resistant to solvents, oils and acids, non-flammable, oil and petrol resistant, therefore it is used at gas stations and fuel stations. Due to its additional water-gas-tight properties, it is considered a universal waterproofing agent for outdoor work. Thiokol sealants withstand temperatures from -500 to +1300 degrees, keeping all their working qualities unchanged.
Heat-resistant silicate sealants-pastes of the heat-resistant group are used as a connecting element during installation and filling of joints and cracks in structures. They contain sodium silicate, which gives them a black color. The main area of their application is directly related to the effect of fire. They are able to withstand maximum temperatures: +1000, +1200 and even +1500 degrees Celsius. Therefore, they are used directly in fireboxes and internal surfaces of fireplaces and stoves. Among their features is instability to deformation and movement. Such pastes have good thermal conductivity, but they are not recommended for outdoor use.
High-temperature sealants-gaskets are used in pump engineering, when carrying out repair work on a car, compressors, in a word, wherever deformation is carried out and there is movement. The thickness of the gaskets is only six millimeters, but they perfectly withstand any mechanical stress, have increased strength and stability. The composition has high heat resistance.
Silicone sealants are the most common and versatile quality sealant. Its operating temperature range is from +300 to + 600 degrees Celsius. They are flexible and easy to apply. Silicone sealants are not stained, therefore the product range of this product has ready-made color solutions. When solidified, silicone sealants form an integral whole with the surface. They are not reapplied, otherwise you can nullify all the work and re-seal.
Silicone formulations are not used to fill deep surface crevices. The composition for vulcanization requires a special environment with high humidity, and it does not penetrate into deep seams. The speed of hardening of the sealant depends on the external temperature: the higher it is, the faster the process takes place.
Silicone sealants are composed of synthetic polymers and are of two types: acidic and neutral. The acidic high temperature sealant is applied as usual, but its peculiarity is that during the oxidation process it releases acetic acid.
The narrow specialization of this type of sealant does not allow it to be used in combination with natural materials: stone, wood, iron and cement. On contact, it interacts and destroys the surfaces of structures on a natural basis. In this case, areas of leaching or rust are formed.
The neutral sealant contains solvent-free, heat-resistant silicone. It does not contain aggressive substances, is easy to use and, when interacting with various materials, releases only water and butyl alcohol. Sealing compounds based on sodium silicate, the so-called silicate (oven) sealants, are neutral.
The synthetic polymers included in the composition provide high heat resistance, which allows them to be used at temperatures of +1200 degrees, for a short time - up to +1500 degrees Celsius.
Their area of application is areas and surfaces in contact with fire. Silicate sealants are used to seal seams and defects in the heating system, boilers, hot water pipes, electric and gas stoves, fireplaces, chimneys. They are also used as a cushioning material. These state-of-the-art, innovative formulations completely displace asbestos. In contrast, they are safe and free of carcinogens. Absolute adhesion to the surface completely eliminates heat loss and all kinds of fuel leaks.
Unlike silicone sealants, silicate sealants are afraid of vibration. After their application, any movements and vibrations are undesirable. Otherwise, a depressurization of the system may occur.
Sealing preparations also include adhesive sealant. It also belongs to the group of synthetic polymers and, in addition to sealing properties, has good adhesive properties.
For repair and maintenance work on furnace equipment and chimneys, an adhesive composition is used to seal the bases. It does not enter into chemical reactions with salts and acids, does not depend on environmental conditions, is oil-resistant, water-gas-tight and therefore can be used to repair gas heating systems, as well as water supply and sewerage systems.
Hybrid sealants based on isocyanates and solvents are very relevant today. They can withstand temperatures up to +1200 degrees. The main component of such sealants - MS-polymer - is a polyester compound (polyurethane), which, in combination with elements of the silicon group, enters into an oxidation reaction and creates a kind of organic cell, vulcanizing the polymer. The composition acquires intumescent properties and hardens.
These compounds are highly resistant to atmospheric precipitation, light and heat. Due to their resistance to alkalis and acids, they are indispensable in the chemical industry.
Homemade sealants are obtained by adding the necessary elements to the base to give the composition the necessary properties and qualities. For example, if fungicides are added to the sealant, the product acquires anti-mold properties. The structure treated with this composition, in addition to heat-resistant qualities, also acquires moisture-resistant properties.
Sealants are traditionally produced in vacuum-packed tubes with tips of 300-310 ml each. Packages of this type of product may differ slightly from each other in terms of size and price. Special assembly guns are available to make it easier to squeeze out the composition. They are convenient for filling seams and cracks when repairing and installing stoves, chimneys, fireplaces and other structures. The seams are smooth and neat. The consumption of the composition directly depends on the properties of the treated surface. Thermal sealants are also commercially available in tubes of 100 g, which are used on a small scale.
Colors
Silicone formulations are available in tubes with ready-made color solutions, since this type of formulation cannot be stained. The scope of their purpose varies from household to professional. They take on the final color after the layer has dried.
High-temperature sealants are, in fact, white in color, but they acquire one or another shade depending on the characteristics of their content. So, red means that the main ingredient of the sealant is acetic acid.
Acetic acid-based silicone sealants are available in all shades of this palette, from brown to pink. The presence of special ingredients dictates the scope of each of them. For example, high-temperature silicone sealant "Moment Herment", which has a red-brown color, is used to join and seal iron surfaces.
Red sealants are used to replace various gaskets, gearboxes, manifolds, oil pumps and so on. Due to their high adhesion and strength, they successfully withstand deformation and are resistant to temperature shocks. The six-millimeter gasket formed by the sealant is capable of withstanding up to +400 degrees Celsius. Heat-resistant sealant contains sodium silicate, which determines its black color.
Silicate sealants contain iron oxide, which gives them a gray color. Compounds with copper have a characteristic reddish tint. High temperature transparent colorless silicone has good elastic properties. It cures well, forming a strong, fast-hardening sealant. The composition withstands high temperatures, has high technical characteristics, which include excellent adhesion to smooth surfaces.
The scope of its application is different: from sealing heat supply devices to sealing glass seams of a car. Colorless sealants are used in optical instruments. They are used to glue glass and metal surfaces, as well as plastic and rubber. Sealants set quickly at room temperature and are used without additional gaskets. Fully hardened in a day from the moment of application.
Manufacturers
Today, manufacturers of high-temperature formulations present an extensive selection of sealants. Each type of this product has its own characteristic features and advantages, which makes it possible to use them in industry, construction and in everyday life.
Products of Estonian brand Penosil… Among the advantages of this manufacturer are the ease of use, as well as the good price-quality ratio of this type of high-temperature sealants
Among the leading manufacturers of this type of product is also Belgian Soudal company… High-temperature formulations of this brand are characterized by high quality indicators, service parameters and shelf life. Prices for goods of this group of this manufacturer on the sales market are slightly higher than their counterparts
Among the brands of domestic products - innovative development "Silotherm", created specifically for fire protection of metal, building and other structures. This is a high-temperature fire-resistant coating - the paint has all the functions of fire protection, is resistant to chemical influences and aggressive environments. Fire-resistant paint is manufactured using domestic technology. It is intended for use in industry, but the scope of its application is much wider. This type of refractory coating can be used to protect various structures in the construction and domestic sectors. It does an excellent job of insulating gas, water, smoke and fire. Among the manufacturers of these products - CJSC "Elox-Prom"… The company is represented on the Russian market by a line of "Silotherm" products for various purposes and properties
Some brands of this type of product are especially popular. Among such as "Methylan", "Macroflex" and "Tangit" is included and "Moment" with an impeccable reputation. The quality of these brands has been confirmed by many large industrial enterprises that have been using their products for several decades.
A wide range of temperature-resistant sealants is represented by high-quality heat-resistant sealants "Moment Herment"designed to protect joints exposed to high temperatures in heating systems, for the repair of automobile engines. It is heat resistant up to +260 degrees.
It is also used in the form of gaskets and for bonding metal structures.
Scope of application
The special properties of high-temperature sealants are widely used in industry and construction. Heat-resistant sealants are widely used in professional and household applications. The difference is that professional grade formulations have properties to withstand higher temperatures.
High-temperature silicate sealants are used in the construction and repair of furnace equipment, for sealing flue pipes, filling any damage, cracks and seams in concrete and other structures. They are used in electrical and installation work.
They perform a protective function and are indispensable for sealing chimneys on the roof, for repairing a stainless steel chimney.
To seal stainless steel chimneys, silicone sealants are used, which have good water and thermal insulation properties.
Sodium silicate based exhaust manifold sealants contain clay, fiber optic and metal shavings. They are ceramic and are designed to protect the engine from combustion products. They are used for the installation and repair of the engine system, reducing the level of exhaust, which excludes the penetration of toxic substances into the car body.
The composition for fixing bearings is particularly durable, intended for connections of couplings and bolts and other equipment. Its area of application is shipbuilding, automotive and other mechanical engineering industries.
Special types of plumbing sealants are used to seal threaded joints of plastic and metal pipes in water supply systems. In addition to heat resistance, they have properties that provide good adhesion to the bonded metal and plastic surface. Anaerobic sealant for fixing threads has advantages over fum tape and plumbing thread - it quickly sets and reliably bonds the elements: applied, attached, and can be used.
A special heat-resistant silicone sealant is used for the installation and sealing of hobs in domestic and industrial premises. Hobs can be gas or electric. Their metal or stainless steel body is equipped with glass and ceramic elements, so the material for sealing must have adhesive properties and good thermal insulation. In industrial panels, there are structures made of metal and cast iron, therefore, the requirements for adhesion when sealing these surfaces are different. The panels are glued and secured using silicone sealants, providing maximum protection against fire and gas leaks.
When sealing the oven, the exposure temperature must be calculated correctly. You also need to take into account the factor of mechanical damage, since the ovens are subject to frequent movements, which leads to abrasion of the insulating composition and, over time, requires a new seal. Unlike them, bread makers are fixed, as they say, "tightly", and do not need frequent sealing.
Silicone temperature resistant sealants are also used for sealing, installing and repairing water heating boilers, steam rooms and saunas. The differences between glass and water mixtures are in the hydro and thermal insulation of aquarium surfaces and pools.
For external work, when gluing sandwich panels, water-resistant types of thermo-sealants are used, which provide moisture resistance and heat resistance. In everyday life, heat-resistant sealants are used to repair irons and kettles.
Thiokol sealants are used wherever it is necessary to eliminate exposure to chemical liquids. The scope of their application is industry. They are in demand at filling and fuel stations and gas stations.
Thiokol and hybrid sealants are used in the aerospace, aviation and mechanical engineering industries. Due to their high resistance to environmental influences, they are widely used in the field of construction and electrical engineering. Due to their moisture permeability and adhesion, they are used in the installation and repair of metal structures of roofs and ceilings.
In the industrial field, these types of sealants are used in the production of railways and other types of transport that carry out road transport. Their properties significantly affect the weight of any product, making it lighter, which leads to savings in energy consumption. Assembly and installation is also accelerated. Sealant replaces welding work, and bolts, nuts and screw connections are simply unnecessary. This cost savings provides the main advantage of this type of seal. This is far from the whole range of use of heat-resistant sealants.
How long does it dry?
High temperature sealants dry differently after application. Some species take 24 hours to dry completely. It all depends on certain properties and types of compositions. Some harden after a few minutes, while others need more time to adhere to the surface. The quality of the bonded surface as well as the ambient temperature are also important factors in the drying speed.
Each tube of sealant is supplied with detailed instructions indicating the time for complete drying. It is important to follow the instructions carefully for a successful application.
See below for more details.