What are the types of heat-resistant sealant for stoves and fireplaces

To prevent cracking of bricks, sealing joints of masonry, cast-iron elements, it is no longer necessary to use cement and clay mixtures. The high temperature sealant tightly closes the gaps, eliminating the risk of smoke escaping and damage to materials at high temperatures. The paste is selected taking into account the limiting temperature regime, adhesion strength, and curing speed.

Purpose of heat-resistant sealants

When used in intensive mode, the fireplace or stove is subject to cracking. Crevices also occur on units without cladding, plastering and high temperature coating. Depressurization of the chimney, furnace and other structural elements leads to the following consequences:

• an increase in fuel consumption when additional air masses enter;
• the penetration of soot into the room - a black coating appears on the walls or ceiling surface;
• human poisoning with combustion products;
• damping of fire - in case of violation of the integrity of the chimney;
• settling of soot on the inner surface of the flue ducts due to the combustion of fuel at low temperatures;
• ignition of the chimney when oxygen is available.

To protect stoves and fireplaces from these problems, a heat-resistant sealant must be used.

Areas of use

Refractory pasty material is used for several purposes:

• treatment of the connection of a ceramic or metal flue duct;
• quality assurance of joining parts of sandwich chimneys;
• organizing a pipe outlet to remove smoke through the roof and rafters - the apron gaps are filled with sealant;
• waterproofing of seams of furnace devices and chimneys;
• installation of cast iron parts (furnaces, ovens, hob) and repair work;
• restoration of the strength of mortar for masonry, destroyed under high temperature load;
• finishing the body of the stove or fireplace structure;
• gluing heat-resistant gaskets made of asbestos or graphite-asbestos cord on doors, ovens, plates, valves.

Some pastes can be used when repairing fireclay masonry, but subject to a maximum temperature in the firebox of up to 1500 degrees.

For threaded connections

Heat-resistant silicate-based polymers withstand temperature drops from +1200 to +1500 degrees. This makes it possible to use them in the areas of seams and damage to the heating system - boilers, nozzles, electric and gas-type ovens. The material is used as a pad, which excludes the release of carcinogens. The quality of adhesion to the surface helps to protect against heat loss and fuel leakage.

For stoves and fireplaces

High temperature resistant synthetic silicone materials suitable for sealing joints in areas of contact with fire. Deep cracks cannot be filled with them, but they can be used for surface treatment with preliminary wetting of the surface.

The best option for repairing furnace units is glue that is not exposed to chemicals, oil and corrosive gases. Solvent-MS-polymer hybrids give a good connection. During oxidation, the paste cures and hardens firmly.

For chimneys

Silicate-based thermosealant for brick chimneys of furnaces allows sealing joints and cracks. The high degree of moisture resistance ensures outdoor use. The material is not suitable for flue ducts exposed to vibrations.

Master Flash Silicone Heat Shrink Tape is used as a seal for metal chimney pipes. The strip covering the joint melts when exposed to temperature. The seam becomes reliable and tight.

Varieties of compositions

For ovens, you can choose a high-temperature sealer with a different thermal insulating base. The first group of materials is available in the form of compositions that can withstand direct exposure to flame, the second - in the form of pastes.

Silicone based

The heat-resistant composition is colored red-brown due to the addition of iron oxide. Pastes can withstand temperatures from 170 to 300 degrees, do not lose elasticity after drying, and are not subjected to deformation loads. Silicone sealant is a non-paintable waterproof material with the following technical parameters:

• packaging - 310 ml tube;
• drying time - about 20 minutes;
• application features - on a cold base at positive temperatures (up to +40 degrees);
• the depth of cracks for sealing - from 6 mm;
• resistance to UV exposure.

Using the paste, you can process a brick chimney from the street side, seal the joints of the roof with an exhaust hood, a chimney made of brick, metal if there is a boiler with an efficiency of 90%. The product is also used to seal external cracks in the brickwork of fireplaces, heating circuit threads.

Silicate based

The viscosity of the oven sealant and the black color are due to the sodium silicate in the composition. The mixture loses its elasticity after hardening, therefore it is suitable for heating equipment with low vibration loads. Differs in the following characteristics:

• short-term temperature limit - from 1400 to 1500 degrees, long-term - up to 1300 degrees;
• curing period - 15 minutes;
• maximum seam size - 15 mm;
• packing - in a plastic tube;
• temperature limit of use - from +1 to +40 degrees.

The adhesiveness of the formulations allows the processing of metal, concrete or brick with an abrasive precoat, but is not suitable for stationary parts. Silicate sealant is used for gaps in combustion chambers, stove pipes in a bath, sealing cracks in masonry, cast iron parts, repairing boilers that work for heating.

Sealant adhesives

Synthetic high-temperature compound - adhesive sealant has good adhesive properties. The material is used for treating the base of furnaces, flue ducts. It is resistant to acid-base environment, suitable for repairing gas heating. The water supply and drainage systems are also treated with glue.

Pros and cons

The advantages and disadvantages of a material depend on its basis. The benefits of high temperature silicone include:

• good adhesiveness;
• resistance to humid environment;
• resistance to UV radiation;
• preservation of the integrity of the structure during abrasive action;
• non-susceptibility to temperature fluctuations;
• ease of application.

Among the minuses - the impossibility of painting the surface, processing a wet base. Acid modifications are not compatible with all types of materials.

The silicate heat-resistant composition has the following advantages:

• maintaining integrity when exposed to high temperatures;
• good strength indicator;
• no shrinkage;
• the possibility of subsequent painting of the surface;
• long service life.

The disadvantages of the paste include lack of elasticity, minimal adhesion to a smooth surface.

Properties and nuances of the choice of sealing pastes

The heat-resistant oven sealant has several properties:

• Ability to withstand temperature exposure. Heat-resistant ones warm up to 1500 degrees, heat-resistant ones - up to 300 degrees.
• Good connectivity. Rubber-based silicone materials are used as glue for ceramics, wood, glass.
• Solidification rate. Depends on the number of components. One-component sealant hardens in 1 minute, applied in a layer of 2-12 mm. Two-component (polymer + catalyst) harden in a few hours.
• Color. Determined by additives in the composition. Red ones are suitable for onlay with a layer of 6 mm, they have good adhesion. Black heat-resistant pastes are used to treat the front of the oven. Colorless - they are distinguished by their vulcanizing ability and strength.

Sealants of any color are permanently cured after 24 hours.

When buying materials, you should check the composition. Silicone pastes ignite poorly, and polymer (acrylic, polyvinyl) are highly flammable and leave black soot.

Compositions in tubes for a pistol are economical in consumption. Silicone can be used for outdoor work, silicate - for heated zones, tapes - for stainless steel chimneys, glue - for lining stoves and brick chimneys.

Acidic sealants are not applied to concrete or metal. After hardening, they will begin to corrode the surface. Alcohols from neutral pastes evaporate after application, and the seam remains strong and elastic.

Manufacturers put markers on the packaging by which one can judge the degree of fire resistance (El and numbers), the time of loss of integrity (E), the period of thermal insulation (l).

To seal a seam or surface with high temperature paste, you will need a spatula, gun, and masking tape. The tube with the sealant is installed in the gun, a piece is cut off from the top. A cap is put on the gap. It is better to protect hands from adhesion of the mixture with gloves.

Application features

Heat-resistant materials are applied according to the following algorithm:

1. Surface preparation. Dust, dirt, and the remains of polyurethane foam are removed. The smooth base is trimmed to improve the hitch quality.
2. Crack expansion. The thick paste is applied only in a gap of 5 mm wide.
3. Sealing gaps. Cracks in the furnace or boiler can be removed using the cold method. Chimney gaps are processed using hot technology.
4. Depending on the type of product, the surface is wetted with water or degreased.
5. Masking tape is glued near the gap.
6. Pressing on the pistol grip, apply sealant.
7. Excess material is removed with a spatula.

The masking tape is removed at the first stage of setting the agent - after 5-10 minutes. After that, the time specified in the instructions is maintained.

Popular manufacturers of high temperature sealants

Several brands are popular among Russian users.

Silotherm

EP-100 can withstand temperatures up to +250 degrees. It is used for sealing a masonry joint in a sauna stove or sauna stove.

Ogneza

The manufacturer produces two formulations. GT has the form of a paste, which expands in three planes when heated to 200 degrees. Frost-resistant material eliminates the penetration of smoke into the room. The LTU tape is suitable for the treatment of chimney seams and is characterized by high fire resistance.

Invamat

Acrylic based sealant that prevents open fire from attacking the surface. Suitable for wood, glass, metal.

Moment Herment

A product with a fire resistance limit of +269 degrees is suitable for the treatment of joints. Protects both heating systems and machine motors from high temperatures.

Macroflex

HA-147 product that can withstand heating up to +1200 degrees in long-term mode and +1500 degrees - in short-term mode. The finished seam can be dyed. The sealant will not shrink.

Soudal

The line is represented by two pastes. High-temperature Gasket Seal withstands heating up to +285 degrees, is characterized by constant elasticity, is not exposed to fats and moisture. Fire Resistant Fire Silicone can be heated up to +140 degrees to seal ceilings and walls. Polysiloxane based smoke-proof agent cures in humid environment.

Krass

The material is suitable for sealing cracks in stone materials. The temperature limit is +1250 degrees. The product is moisture resistant, not exposed to the chemical environment. It can be easily applied to metal surfaces or used as a thread sealant.

High-temperature materials are the best choice for sealing cracks or joints in a fireplace, stove structure or chimney. The type of product is selected depending on the operating conditions. Subject to the application technology, any surface can be treated with high quality and reliability.