Thread-locking fluid

Thread-locking fluid or threadlocker is a single-component adhesive, applied to the threads of fasteners such as screws and bolts to prevent loosening, leakage, and corrosion.

Most thread-locking formulas are methacrylate-based and rely on the electrochemical activity of a metal substrate to cause polymerization of the fluid.

Working temperatures for threadlocked fasteners are typically limited to 150 °C (300 °F), which is below the softening point of the methacrylate polymer.

In the case of less electrochemically active metals such as the normally oxidised surface of aluminium, an additional step of priming is required for full strength results.

[5] Lock washers, locknuts, jam nuts, and safety wire may be used in conjunction with thread-locking fluid to prevent loosening of bolted joints.