To ensure the tightness of joints and joints, a special silicone compound is often used. Its peculiarity is the ability to maintain its elasticity under different conditions. Due to this, damage to the connection does not appear even in the case of displacement of the elements. This is one of the advantages silicone joint sealant has . Next, we consider its operational characteristics in more detail. The article will also talk about the scope of application of the composition and application technology.
General information
Silicone sealant, the technical characteristics of which will be discussed below, is a viscous fluid composition. Its basis is special types of rubbers that can harden at room temperature. Universal silicone sealant is used to fill joints and gaps. It provides protection from the negative effects of certain factors. Transparent silicone sealant is also used to fix the elements and glue them together. For the first time, compositions began to be used in the sixties of the 20th century.
Silicone Sealant: Specifications
The composition has many useful properties. Silicone sealant, the characteristics of which determine the scope of its application, has:
- Water resistant.
- Elasticity.
- UV resistant.
- High adhesion to most materials.
- Resistant to aggressive environments.
- Longevity.
- High resistance to significant temperature extremes (from -60 to +300 degrees).
Classification
Silicone sealant for external joints can be one- or two-component. The first are the usual compounds in tubes. One-component sealants can be found in stores and in “foil bags” (special tubes made of film), as well as in larger containers. Hardening of the composition occurs under the influence of air and moisture. One-component sealants are considered the most extensive use of silicone in the world. The compositions reach full hardening at the time declared by the manufacturer when a layer of 2-12 mm is applied. Some manufacturers indicate 15 mm. Two-component sealants can harden in any volume. Such compositions, for example, include Vixint, TF-1, Elastosil, Pentelast. These sealants are less common and are used, as a rule, for industrial purposes.
One component formulations
These sealants come in two types: acidic and neutral. The former have a fairly strong smell of vinegar. Their cost is much lower than neutral compounds. Such sealants can provoke corrosion when applied to cementitious materials, metals, etc. Most of the poor-quality compounds are made acidic. This is due to the cheapness of the feedstock. Nevertheless, in many situations, the optimal solution to the problem is an inexpensive, but high-quality silicone acid sealant. The polycondensation mechanism of the composition is as follows: the terminal hydroxyl groups of polydimethylsiloxane interact in the presence of water with a curing crosslinking agent (for example, methyltriacetoxysilane), with the removal of the acetic acid to form a network structure. Neutral compounds have a faint odor and are more expensive.
Appointment
Silicone sealant for external joints can be construction, automotive or special. However, this classification is rather arbitrary. As a rule, the packaging indicates the main purpose of the composition. For instance:
- "Automotive".
- "Universal".
- "Aquarium". This composition is used for terrariums, aquariums and more.
- "Sanitary silicone sealant." It is used in bathrooms, showers, and bathrooms.
- "Low modulus". Such compositions are used to fill interpanel seams. They withstand varying degrees of deformation.
- "Insulating". This composition is used when working with electrical engineering.
The silicone sealants are not “heat resistant” or “high temperature”. Their main component is water glass (sodium silicate).
Fields of application
Silicone sealant for external joints is used for processing:
- The junction of structural elements.
- Perimeters of openings.
- Items subject to heat.
Many compounds are used for sealing joints of walls and showers, gluing mirrors, processing joints of water and sewer networks, adjoining plumbing objects.
Poor mixes
There are a lot of such compounds on the market today. Of course, manufacturers can also have defects in quality material. But among the total volume of production, its share is small. Manufacturers of low-quality goods reduce the cost of production by diluting the feedstock with any organic compound. They, for example, can be oil or kerosene. Along with this, the package may be written "100% silicone." When diluting and reducing the proportion of the main component, the operational properties of the products are significantly reduced. Elasticity, mechanical strength, resistance to temperature changes, water, ultraviolet are deteriorating. After application, shrinkage will appear over time. The composition itself will turn yellow or darken, lose shape. The durability of the seal is also reduced. In some cases, the composition does not harden. In this case, after any period, the sealant begins to "smear". This property is considered the norm for glass compositions, since the main component is constantly changing its shape in the frame. But this phenomenon is completely unacceptable for other sealants.
disadvantages
Many believe that silicone sealant for external joints is an indispensable composition, and its possibilities are unlimited. However, this is not quite true. There are a number of drawbacks that a sealant has. For example, most formulations are not intended to be applied to wet surfaces. High-quality sealants (undiluted with large volumes of organic compounds) cannot be painted with ordinary dye. Not very good adhesion is observed in the composition when applied to PTFE, polycarbonate, PVC, polypropylene, polyethylene. This problem is often solved by acquiring more expensive professional staff or by using “sublayers” that enhance adhesion before using sealant.
Instructions for use
As practice shows, there is nothing super complicated in the process of applying sealant. For convenient use of the composition, you should purchase a special gun. A tube with a sealant is inserted into it. The tip of the nose is cut with a knife. A special dispenser included in the kit is wound on top. It also needs to be cut off in a certain place so that it becomes possible to control the amount of substance supplied. Before applying sealant, the surfaces are cleaned and dried. Almost all formulations do not adhere to a wet base. In other words, applying to a wet surface is ineffective. If necessary, seal the joints in wet conditions, you should use special sanitary compounds. They will not lose their properties even in such conditions. Adjacent decorative surfaces should be protected with masking tape. The piston of the gun should be pressed gently, evenly distributing the mixture along the joint. The remainder of the composition is removed with a damp cloth. To clean your hands using ordinary soap. Removing excess sealant is best done before it hardens. Otherwise, a mechanical cleaning method will have to be applied.
Silicone Sealant "Moment"
This composition is designed to protect against draft and humidity. The joints and seams treated with this sealant look quite neat. The strength and elasticity of the composition remains for many years. The manufacturer claims that the durability of the seam is 10 years. The composition is harmless and able to maintain its operational properties at temperatures from -40 to +100 degrees. Full hardening occurs within 2-4 days. The composition provides a flexible and durable seal. The product is not stained. In this regard, to expand the scope of application, the composition is available in white and transparent. The first is recommended for sealing windows and white bathtubs. To fill the joints in sanitary ware of a different color, it is more expedient to use a colorless composition. Transparent silicone sealant is also recommended for bonding a variety of small elements including those that may come in contact with water.
The tube is equipped with a metering nozzle and a rotary key for economical and uniform extrusion. Sealant "Moment" is successfully used not only in apartment conditions. With its help, joints are processed in pools, greenhouses, greenhouses. The composition is also used in the repair of
garden tools made of solid polyvinyl chloride and
anodized aluminum.