A sealant is a material used to fill cracks and impart tightness. For the right choice of hermetic composition, you need to figure out exactly where it will be applied.
In general, sealants can be divided into silicone, acrylic and polyurethane. Which type to use in each case depends on a number of factors, such as temperature fluctuations, external influences, compatibility with the surface material and others. We will consider silicone sealants.
Due to the elasticity, silicone cannot be coated with paints and varnishes, but this is compensated by a fairly wide range of colors. There are transparent, black and colored silicone sealants.
Sealants can be divided into two groups.
- One-component compositions do not require additional actions. They are completely ready for use, so they are widely used in everyday life.
- Two-component sealants consist of a base and a hardener located in different vessels. They give a reaction only as a result of mixing. They are mainly used in industry.
One of the one-component sealants is silicone. It can be acetate and neutral.
In the first case, the material contains acetic acid, and in the second, alcohol. Due to this, acetate sealant should not be used with metal, stone and concrete, since acid can have a negative effect on them. Neutral sealant easily copes with such problems.
Due to chemical inertness, neutral silicone sealant can be used in various fields. It interacts well with metal surfaces and glass, is used at the joints of concrete and cement structures, and is used in shipbuilding and aviation.
Black silicone sealant is an indispensable tool for technical work with cars. The scope of its application in this direction is quite wide.
The composition is waterproof, well tolerates various automotive fluids.
The only exception is gasoline, its contact with the treated surface can adversely affect the properties of the material.
This type of sealant can withstand short-term exposure to high temperatures, which can reach 300 degrees. When applied, it does not flow; it is characterized by reliability and durability during operation.
You will learn more about the characteristics of silicone sealant by watching the following video.
How to choose?
Experts say that the quality of the sealant directly depends on the amount of silicone in its composition. One hundred percent silicone compound is considered the best. It does not shrink, has a long service life and can withstand mechanical stress. The disadvantage of this material is its rather high price.
The introduction of additives in the composition of silicone sealant can reduce its hermetic properties , so it is worth choosing a composition with a minimum number of additional components. The amount of additives can be determined by the weight of the product. A package of 85 g of pure silicone should not weigh more than 95 g. If the weight turns out to be more, this means the presence of fillers.
It will also be useful to determine whether a solvent has been added to the composition. This is revealed by applying silicone to polyethylene. If the composition is clean, the surface under it will not wrinkle and swell.
Features of work
Working with black silicone sealants does not cause any particular problems:
- for convenient application of sealant it is worth using a special gun;
- after opening the package, a dispenser is put on the remote tip of the nozzle, which must be cut off depending on the required supply volume of the product;
- dirt and dust must be removed from the surface, treated with sealant, and thoroughly dried;
- excess silicone should be removed from the coating before it hardens, after which it will be possible to clean it only mechanically.
Features and Overview
One of the most popular silicone sealants is Sikasil SG-20. It is used to repair and create tightness during construction work.
Sikasil SG-20 sealant is used for fastening facade elements, filling joints and cracks. He has established himself as a composition for window structures and structural glazing.
The material is packaged in a container of 310 and 600 ml, as well as 20 and 200 liters. It is ready to use, does not contain solvents, practically does not shrink. The temperature regime during work should be from 5 to 40 degrees above zero.
Sikasil SG-20 glue perfectly interacts with almost all types of surfaces , is characterized by moisture resistance and can withstand adverse weather conditions. During application, the sealant does not sag, is durable, tolerates the effects of ultraviolet rays and has an anti-corrosion effect.
Another popular brand is the black Abro silicone sealant , designed to repair gaskets in car engines. It tolerates the effects of specific automotive fluids, except gasoline. With it, you can work with a water pump, valve cover and drip tray.
High-temperature sealant is able to withstand temperatures up to +340 degrees, has an anticorrosive effect and is practically odorless.
Permatex Black Silicone Adhesive Sealant is a synthetic rubber compound that helps withstand temperature extremes from –60 to +260 degrees, does not dry out and does not crack during operation. The treated surface is flexible, but it is leakproof.
This material can be applied on both vertical and horizontal surfaces. It withstands the effects of water and is non-toxic. Adhesive sealant has a good bond with a variety of substrates, such as glass, wood, ceramic and metal surfaces, plastic and others. Full solidification is carried out in a day. The sealant withstands contact with automotive fluids.