What Is Thread-Locking Fluid?


Have you ever installed a fastener, such as a bolt or screw, only for it to wiggle its way out? Even if it doesn’t happen immediately, fasteners can and will loosen over time. This is especially true in applications involving strong and/or persistent vibrations. If you install a screw or bolt where it’s regularly exposed to vibrations, it may work its way out. It may not happen immediately, but over the course of many weeks or months, the fastener may loosen to the point where it’s no longer secure. The good news is that there’s a solution to prevent fasteners from loosening: thread-locking fluid.

Overview of Thread-Locking Fluid

Also known simply as thread-locker, thread-locking fluid is a type of adhesive that lives up to its namesake by “locking” fasteners in place. It’s applied around the threading of a fastener — the threading where the fastener joins a nut or object — at which point it hardens and cures to prevent the fastener from loosening.

Thread-locking fluid has origins dating back over a half-century. It was invented by American engineer and professor Vernon K. Krieble in the mid-1950s. After developing the innovative new adhesive, Krieble went on to found Loctite. Since then, many other companies have produced and sold thread-locking fluid.

How Thread-Locking Fluid Works

Thread-locking fluid is classified as an adhesive, and like all adhesives, it’s able to bind multiple surfaces to which it’s applied. Fasteners such as screws and bolts tend to loosen over time at their respective threading. If you drive a screw or bolt into an object, the fastener may loosen at the threading where it’s installed. Thread-locking fluid prevents this from happening by binding the fastener to the object. Even if the fastener is exposed to strong and/or persistent vibrations, it shouldn’t loosen thanks to the thread-locking fluid.

Most formulas of thread-locking fluid consist primary of methacrylate. As a result, it’s able to cure without the need for oxygen. Thread-locking fluid can be applied in deep crevasses where there’s little or no oxygen. Regardless, it will cure because of its anaerobic properties. It’s also worth noting that thread-locking fluid is thixotropic. In other words, its viscosity increases over time.

In Conclusion

Thread-locking fluid is an adhesive that, when applied to a fastener, prevents the fastener from loosening. It’s frequently used on bolts and screws that would otherwise loosen from vibrations. If you’re thinking about using fasteners in an environment where vibrations are problematic, you may want to lock them in place with the help of thread-locking fluid.