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All you need to know about plane sealing

What is a plane sealing product ?

Plane sealing products, such as silicone-based and anaerobic sealants, are designed to prevent leaks of liquids or gases between two contacting surfaces. These solutions are crucial for maintaining the integrity of assemblies in a variety of environments.


These products, made of silicone polymers, are exceptional for their performance under extreme conditions. They withstand high or low temperatures, humidity, and UV rays well. Frequently used in construction and industry, they ensure sealing around windows, doors, and in bathrooms, as well as for industrial components exposed to harsh environmental conditions. Their flexibility, durability, and ability to adhere to various materials make them indispensable for many applications.


Anaerobic sealants, which cure in the absence of air and in the presence of metals, are ideal for mechanical applications where space is limited. They are particularly used to seal threads, bolts, and other metal assemblies, thus preventing leaks and loosening due to vibrations. These products fill gaps and irregularities between surfaces, offering durable sealing without the need for external pressure. They are also appreciated for their ability to handle tolerances in assemblies, avoiding the need for costly or complex surface finishes.

These two types of sealing products offer specific benefits depending on the application. Silicone products are chosen for their resilience in harsh environments and their adaptability to many materials, while anaerobic solutions are preferred for their efficiency in confined spaces and their resistance to vibrations and corrosion. The choice between silicone and anaerobic depends on the specific requirements of the application, including the need for resistance to temperatures, humidity, and chemicals.

How to choose a plane sealing product ?

Choosing between a silicone sealing product and an anaerobic product depends on the application, the type of materials, the usage environment, and the physical properties required for the seal.

The use of a plane sealing product helps to avoid various causes of joint failure or leakage such as relaxation, displacement, bulging, or deformation of the joint.

These products allow for increased reliability of the installation, improved safety, reduced costs, and time savings.

The choice of sealing product depends on the type of joint: machined rigid joint planes or flexible joint planes.

For a machined rigid joint plane, an anaerobic is preferred, which allows for almost no gap between the two metal pieces.

For a flexible joint plane, a silicone sealant is advised. This material allows for greater tension and can fill larger gaps.

Silicones cure by reacting with the moisture in the air, while anaerobics require the absence of air and the presence of metals to cure. Silicones are more versatile in construction and industrial applications for their physical properties, while anaerobics are specifically designed for metal assemblies and mechanical applications.

The Loctite range

Loctite stands out in the sealing market with its innovative solutions, especially in the field of plane sealing.

Within this range, two products stand out for their efficiency:

  • Loctite 518, an excellent example of anaerobic sealing.
  • Loctite SI 5910, representative of silicone sealing.

Loctite 518

Specifically formulated for machined rigid joint planes, Loctite 518 is placed between two metal surfaces without requiring external compression to seal effectively. Its anaerobic composition allows it to cure in the absence of air, offering a perfect solution for assemblies requiring almost no gap.

Ideal for sealing gearboxes, pumps, and housings in the automotive and heavy industry, it allows for total sealing, rapid polymerization, and easy disassembly if necessary.

Loctite SI 5910

For flexible joint planes requiring greater adaptability, Loctite SI 5910 offers a versatile silicone solution. This product cures by reacting with the moisture in the air, thus filling larger gaps and adapting to various materials.

Used in construction for expansion joints, sealing around windows, doors, and in bathrooms, as well as in the industry to protect components against severe environmental conditions.

It exhibits excellent resistance to extreme temperatures, humidity, and UV rays. It adheres to a wide range of materials, offering flexibility, durability, and effective protection.

The choice between Loctite 518 and SI 5910 will depend on the specific application, the type of surfaces to be joined (rigid or flexible), and the conditions of use. Loctite 518 is preferred for metal assemblies where precision is crucial, while SI 5910 is ideal for scenarios requiring greater flexibility and resistance to the elements. Each product is designed to maximize the reliability of the installation, improve safety, reduce costs, and save time.