Today, not a single construction site or repair can do without sealants. They are simply necessary in cases where you need to seal the joints at the joints of concrete slabs, or you need to achieve impermeability of various joints. Sealants are used both on large-scale construction projects and at home.
There are a lot of types of sealants. Let's consider today one of the types - thiokol sealant and try to figure out what it is, what are its strengths and weaknesses.
Features of the
Thiokol sealant is a vulcanizing paste made of two or sometimes more components. Such materials are considered the most reliable due to their special adhesion strength. This sealant is based on liquid thiokol, similar in properties to polysulfide rubber.
Therefore, thiokol sealants are also known as polysulfide sealants. In addition to rubber, various fillers can be added to the thiokol paste: plasticizers and structuring materials, polymers and coloring pigments. The paste is usually gray or black in color.
After mixing all the components, a kind of elastic paste is obtained at the exit, designed to protect the surface from moisture and other negative phenomena.
Positive qualities of thiokol sealant:
- non-flammable, oil-resistant;
- not subject to oxidation and alkalinity;
- does not change its properties with prolonged exposure to direct sunlight;
- does not collapse at high and low temperatures, is able to withstand temperature drops from -55C to + 130C;
- provides good adhesion to wood, metal, glass and other hard surfaces;
- not afraid of moisture, therefore it is ideal for sealing external and internal cracks in buildings for domestic and industrial purposes.
Scope of application
Thiokol sealant has a wide range of applications.
- In aviation - sealing of fuel tanks, technical compartments, windows, sealing of an electric cable, when laying the runway at airfields.
- In shipbuilding - sealing the cable box, eliminating cracks and holes in wooden surfaces (decks, wooden frames, etc.), sealing pipe connections, protecting steel parts from erosion.
- In the automotive industry, they provide the strength of fastening of auto glass, protect metal parts from corrosion and abrasion, and seal welded seams.
- In the electrical, technical and food industries - sealing tanks for storing food liquids, filling cable soldering points, fastening parts that cannot be soldered, since they cannot withstand high temperatures or the surface can be damaged. The sealant is used in the assembly of household appliances - refrigerators, washing machines and others.
- In the space industry, they are used as protection against ultraviolet radiation, exposure to oxygen, and provide a vacuum.
- In medicine, imprints for dentures are made from thiokol mastic.
- In construction, polysulfate-based sealants are widely used to eliminate cracks and impermeability of building wall joints in order to protect them from moisture ingress and to avoid heat loss.
Among the disadvantages of thiokol materials, several factors can be noted
- Not suitable for plastic surfaces. The solvent contained in the sealant has a negative effect on it.
- When mixed with a hardener, thiokol paste must be used within a few hours, after which the material is unusable.
- The sealant is toxic and can cause allergies and even pulmonary edema. Therefore, when working with it, it is necessary to observe safety measures and use protective equipment - gloves and a respirator.
- Higher cost compared to other types of sealants.
- Difficult to work with. Unlike other types of building pastes, which can be packaged in convenient tubes, thiokol mastic is sold in a wide container, which creates some difficulties when applying a uniform layer.
When studying the technical characteristics of this material, several main brands of thiokol sealants can be distinguished.
U-30M. Density 1400 kg / m2. The tensile strength is 2.6 MPa. It is widely used for products that have constant contact with air, since it is resistant to natural atmospheric aging. It is also used to create flexible waterproof coatings. This brand has proven itself well in contact with gasoline and other petroleum products. But it is not recommended to use this sealant on silver, brass, bronze, as well as copper surfaces that have not been previously treated with anti-corrosion varnish - this brand has poor adhesion to them
UT-32 used in electrical equipment with metal elements - rivets, plugs, bolts and other parts. The technology of applying this brand of sealant does not require preliminary application of an adhesive layer
Like the previous brand, UT-32 is highly resistant to engine oils and gasoline. And she also cannot contact with brass, copper and silver.
At the same time, it has a higher density than U-30M (1700 kg / m2), and withstands the temperature range from 60 C to +130 C. Tensile strength 1.27 MPa.
- U-30MES5M. In addition to traditional use in various fields, the sealant can also be used as an adhesive for the installation of individual assemblies and parts. It can function as a protective layer against corrosion and weathering. It can be used for interior work, as well as for joining elements of various equipment.
- UT-34. It is used in engineering, aviation, electrical, technical industries, in the construction of tanks, shipbuilding, in the construction of civilian facilities. The density of this sealant is 1600 kg / m2. It can be operated at temperatures from -60 C to +150 C.
- VITEF-1NT recommended in cases where contact with aluminum and magnesium alloys, as well as cadmium steel, is expected.
Due to its wider range of applications, it is especially popular with buyers. The density of the sealant is 1600 kg / m2, and the tensile strength is 1.76 MPa.
For information on how to choose the right sealant, see the next video.