The science behind the working of a threadlocker is quite complex. The fluid uses electrochemical activity to form a very strong bond between the two metal surfaces. In other words, the fluid reacts with the metal surface and undergoes polymerization. The process of polymerization leads to formation of a very strong bond that can handle great forces. The thread-locking fluid has other numerous functions apart from creating a stable lock between fasteners. It is used to create an airtight condition hence preventing leakage of fluids where fasteners are used in reservoirs.
The threadlocker comes in two main versions. These are the permanent and temporary versions. The permanent version is applied once throughout the lifetime of a component and is used to form permanent joints. In other words, once the bond is formed, the fastener cannot be screwed out of place for repairs to be conducted. The permanent type can withstand shear forces of up to 21 MPa. This is an equivalent of 3000 psi shear force. The temporary type on the other hand can be removed easily when need arises. In most cases, bond breaking is done by heating the joint at high temperatures.
Permanent locking of fasteners using a threadlocker is not completely effective when the component is exposed to very large forces. A backup plan should be used to ensure that the fastener remains locked at all times. Therefore, most engineers design machine parts that are compliant with the thread-locking fluid coupled up with jam-nuts, locknuts, lock washers, or safety wires. These tools ensure that the bond formed cannot fail in the occasion that shear forces exceed the maximum stress that the thread-locking fluid can withstand. With a combination of the two locking mechanisms, a very stable joint is formed.