What Is Retaining Compound?


Bearing Retaining compounds are a type of anaerobic adhesive that is critical for the accurate assembly of both press-fitted and slip-fitted parts in mechanical equipment. It’s used to fill spaces and gaps between various components so that the parts sit flush with each other, minimising movement and maximising stability, especially during periods of high vibration. The solution that makes up retainer compounds cures to form a powerful bond with the metal, creating a stronghold of components and allowing high-load transmission without the use of air, and preventing deterioration over time.

Industrial & Automotive Parts is an industry equipment supplier specialise in providing parts and resources to ensure your vehicle operates at its best and preserves its components, including many different adhesives and sealants. Here we answer the question, ‘what is retaining compound?’ in more detail, as well as explore why it’s used and provide variables to consider when choosing a product.

What is a retaining compound?

As mentioned above, bearing retaining compounds bond active metal surfaces together where there’s no oxygen present. This makes them excellent at binding the metal components of vehicles and machinery, but don't perform well with other materials, such as rubber, plastic or glass. Curing to form strong bonds, the compound delivers precision in the joints between car components to manage well in challenging environments, like high-vibrational equipment. Ultimately, sealed components will continue to handle high-strength requirements and temperature resistance whilst encountering various substrates.

Retaining compound vs. thread locker

Retaining compounds and thread lockers are both adhesives used in mechanical equipment, but they generally have different applications.

Retaining compounds are used to bond compounds together, such as bearings, cylinder liners, and shafts, in order to achieve greater strength and resistance to high temperatures.

In contrast, thread lockers are a fluid applied to fastener’s threads to prevent loosening, leakage or corrosion. They hold tools like nuts, bolts and screws in position whilst under stress, performing a similar function to washers and fasteners. Thread locking fluid is also an anaerobic chemical, meaning it will not require oxygen to cure.

As such, you must recognise your desired application and substrate before choosing between a retaining compound vs thread locker. For example, if your objective is set towards high strength bonding, a retaining compound will be the option to select.

What is Retaining Compound Used For?

Retaining compounds have many various applications because of their strong bonding capabilities. As they fill the space between components while bonding them together, they allow for a much larger transmission of loads, which makes the entire machine run more efficiently and smoothly.

Industrial applications include:

Preventing Fretting Corrosion

As high loads are applied under recurring surface motion, fretting corrosion can occur and wear away the metal. Retaining compounds can be used to create a barrier between the two metal surfaces, preventing them from coming into direct contact, which is especially important for minimising the oxidation of exposed surfaces.


A selection of bearing retaining compound will likely be utilised within a single manufacturing facility. They are best applied in machinery and components holding an assortment of sleeves, bearings, and pins, in addition to slip fit, close fit, shrink fit and press-fit applications. Essentially, retaining compounds can be utilised where any form of flexible and reliable adhesion is required.

General Maintenance, Repair & Operation of Machinery (MRO)

Retaining compounds offer fast and efficient repairs to key areas of machines utilised in a variety of industries, keeping them in working order for longer periods of time and improving wider productivity.


High temperatures are a common aspect of machinery in the automatic industry, making retaining compounds an effective gap-filling solution for components. They can also offer alternatives to save on wider costs, such as shaft repair, rather than replacing the whole component.

Types of retaining compounds

To cater for the various applications and components, there are many types of retaining compounds that serve various needs of different industries. These products can come with qualities such as high strength, high-temperature resistance, low viscosity, fast cure speeds and effective gap filling. Industrial & Automotive Parts provides high-quality retainer compounds designed for these specific applications:

  • General-purpose and tight gaps
  • Large bond gaps
  • Easy disassembly
  • Worn and damaged parts
  • Contaminated surfaces

How to choose the appropriate retaining compound

The key to determining the right retaining compounds for your needs is to assess the function and application to be bonded. These applications include:

High Strength Retaining Compounds

Retaining compounds created to have high strength are commonly used for components that are to be permanently bonded together. In these situations, retainer compounds securely cure the two parts together and reduce the abrasion between metals, even while components endure consistent movement.

Permanent bonds include components that aren't to be separated for the entire duration of the machinery’s useful life, and a high strength compound will ensure they don't come apart. For components that will need to be taken apart, such as during service maintenance or when replacing components in the joint, a compound with a lower strength is preferred for easy disassembly.

High-Temperature Retaining Compounds

High temperature retaining compounds are available in a selection of different formulas and hold various characteristics, yet each with superior handling of higher ambient temperatures. These options are best suited for automotive and MRO applications, given a high thermal operation of components can be expected.

Gap size

Adhesives typically come with different viscosities as thinner compounds can fit into tight gaps, while thicker ones can fill more space. Large gaps often need to be filled in mechanical equipment as it’s difficult to perfectly fit parts. Retainer compounds that seal large gaps have a high viscosity, usually above 2,000 mPA.s and can bond parts with a gap larger than 0.15 millimetres.

Compounds with lower viscosity can fill smaller gaps between parts effectively. General-purpose and tight gap retainer compounds are critical for parts that are in close contact, as these compounds are thin enough to enter these gaps while sealing the joint and reducing damage.

Cure speed

Typically, when applying adhesive to vehicle parts, cars are unavailable and parked so there is enough time for compounds to cure. Fast curing speeds are often used in production lines and industrial equipment that doesn't allow much downtime, so parts can be serviced quickly. These compounds turn into a solid quickly and secure the joint in minutes.

Vehicle components typically benefit from higher strength compounds with longer curing times. For industrial equipment, you can minimize downtime by selecting a fast-curing speed for bonding parts together, however, ensure it also has high strength and temperature resistance if required.

Review our wide selection of bearing retaining compound, electric motor suppliers or ball bearings online available, or for more information on what a retaining compound is and retaining compounds vs thread locker, contact us at Industrial & Automotive Parts today.