In construction, it is often necessary to seal cracks and seams exposed to high temperatures. Means for solving such problems must simultaneously withstand temperature fluctuations and maintain plasticity. A real breakthrough in this area was the invention of a special composition, which is based on silicone rubber.
Design Features
Before applying silicate pastes, the surface must be moistened. Heat-resistant silicone should be used at temperatures between +5 and +40°. If the ambient temperature drops below zero, then the composition simply will not harden. The optimum temperature for use is + 20 °. The artist should definitely use personal protective equipment in the form of gloves, as sealing silicone mixtures may contain substances that can cause chemical burns on the skin.
To avoid contaminationsurfaces that are not to be sealed, masking tape should be used on their bases, which is glued on both sides of the seam. Experts advise to strictly adhere to the instructions, which provide for compliance with the thickness of the seam, it should not be more than recommended. This is due to the fact that there is a risk of cracking during operation of the material, which may not harden.
Varieties of sealants
Heat-resistant silicone is based on polymers, which can be completely different, which gives the composition certain characteristics. Such mixtures are sold in tubes, which can have different volumes and configurations. On sale you can find two-component compositions that require mixing before starting work. Quite often they are used by professionals for the reason that stringent requirements are imposed on the composition. When mixing, you will have to measure the parts, strictly following the instructions. However, the error is still acceptable, but it is only 1 g. If the ingredients are mixed incorrectly, a reaction will occur, and the usability of silicone is only a few hours.
To solve everyday problems, it is best to use one of the varieties of silicone sealants, which is presented in paste form, as they are easier to use. For furnaces and chimneys, it is recommended to purchase high-temperature compounds; they are offered for sale in the form of heat-resistant, heat-resistant and heat-resistantmaterials.
Features of Heat Resistant Sealants
Heat-resistant silicone is one of the varieties of the compositions described and is used for places that will heat up to 350 ° during operation. Their scope is the outer surfaces of fireplaces and slots. With the help of a heat-resistant sealant, gaps between bricks in the masonry can be sealed. However, a heat-resistant sealant should not be used between furnace casting. It can be used to seal sandwich panels and roofing, as well as brick chimney joints.
But there are exceptions to this, which are expressed in metal chimneys. But you can close the gaps in the hot water heating system using a heat-resistant sealant.
Description of heat resistant or heat resistant sealants
Heat-resistant silicone can be presented in heat-resistant or heat-resistant form. These compounds are able to withstand temperatures of 2500 °. If we are talking about a fireplace or stove, then the scope is limited to masonry and casting joints, as well as furnaces and combustion chambers in boilers.
For chimneys, a heat resistant sealant can be applied to the articulation and seam areas. This should also include a place near the outlet pipe of the chimney. These mixtures can be used in areas that are in direct contact with the flame. However, before purchasing such a heat-resistant silicone, you should ask if it has fire resistance and fire resistance qualities among its characteristics.
Specifications of heat-resistantsealant
Heat-resistant sealant is made on the basis of silicone. The temperature regime may vary depending on the composition. Thus, iron oxide is added to the ingredients to improve heat resistance. Such sealants cope with exposure to temperatures up to 250 °. For a short time, the temperature can rise to 315 °. If iron oxide is present among the ingredients, the paste will have a reddish-brown tint. Such mixtures are used for fireplaces or stoves made of brick.
The appearance of the surface when sealing cracks will not be spoiled, since the sealant is almost invisible. It is important to pay attention to the composition of silicone sealant, as it can be neutral or acidic. In the latter case, acetic acid will be released during solidification. Such mixtures cannot be used with metals that are not resistant to corrosion.
Additional Features of Heat Resistant Sealants
The mixtures described above are UV-resistant, so they can be used for external work, as well as for sealing the roof passage. They are waterproof and have a high grip. The composition retains plasticity, it does not crack during vibration and deformation. The curing speed can be from several hours to several days, this characteristic will depend on the composition of the mixture.
Specifications for heat resistant sealants
Sealing silicone heat-resistant pastes are designed to fillcracks on surfaces operated at temperatures from 1200 to 1300 °. A short-term increase is possible up to 1600°. Therefore, these sealants are often used in places where direct contact with open flames is possible. If you plan to assemble a chimney or any other structure that will be collapsible, then you need to process the joints. When loosening two links, it will be possible to crumble the sealant and separate the parts. If, however, the glued surfaces are smeared, then the structure will turn out to be almost monolithic, and it will not work to disassemble it without damaging it.
Heat-resistant silicone sealants have poor adhesion to smooth materials, so the surface must be treated with an abrasive before application, and then rinsed and degreased again. It is not necessary to wet the surface before sealing, and the wet composition can be removed with a damp cloth. Some compositions provide for the need to create special conditions. Thus, furnace sealants must dry for several hours at different burning rates. If you follow the instructions exactly, you will be able to get a tight connection or joint.
Description of KLSE silicone sealant for mold making
On sale you can find another type of sealant - heat-resistant silicone for molds. The received products can be operated at a temperature which does not exceed 400 °. If this threshold is higher, then after a while the form will lose its elasticity. The described sealant is a fluid composition that hasbrick color. It is sold as a base and has a catalyst included. Cures within 24 hours at room temperature, resulting in rubber-like products.
The surface of the original, from which it is supposed to remove the form, must be degreased, cleaned of rust and dirt, if the surface is porous, then it is best to use a separating composition. The mixture should be treated with the original product and left in this state for a day or less. If the ambient temperature is lower than recommended, the curing time may increase. It will be necessary to develop a compound in half an hour.
Alternative Silicone Heat Resistant Sealants
If you are looking for heat-resistant gasket silicone, you can choose "Pentelast-1110", which is used as a liquid gasket in joints and for sealing threaded pipelines. It is able to maintain performance at temperatures from -50 to + 250 °. Short-term exposure to high temperatures is also possible, but not more than 10 hours. In this case, the thermometer can rise up to 300°.
There are no toxic and acidic emissions during vulcanization. If necessary, you can also use RTV 118 Q food-grade heat-resistant silicone, which is colorless and is a one-component adhesive-sealant. It is applied at room temperature, and in its original state is a paste. Application can be carried out on horizontal and vertical surfaces. Working temperature rangevaries from -60 to +260°.
More offers
Sheet heat-resistant silicone is also popular when carrying out a certain kind of work. The dimensions of the plate can vary from 300x300 to 500x500 mm. Its thickness varies from 1 to 12 mm. This material is made of silicone and can be used in food equipment at temperatures from -50 to +250°. The products are safe, chemically stable, non-toxic and environmentally friendly. Silicone molding heat-resistant is used for the manufacture of gaskets. The latter can be used to seal fixed joints.
Heat Resistant Silicone Spray is an all-purpose lubricant that preserves and protects metals, rubber or plastics, and wood. With it, you can achieve the elimination of unpleasant sounds. The material creates a waterproof protective film that does not leave greasy stains.
