Quick Tip: The When, Where and What of Threadlockers

In this Brownells Quick Tip, Caleb and Steve take a closer look at something every builder and gunsmith eventually runs into – threadlocker. It’s a simple product, but using it correctly can mean the difference between a solid build and a frustrating repair. In this guide, they explain how to choose the right compound, avoid common mistakes, and keep your firearm secure.

What You Will Learn

In this video, viewers will learn how to choose the right type of threadlocker for different firearm applications, how to apply it correctly, and when it’s best to avoid it altogether. 

Benefit

By understanding the proper use of threadlocker, viewers can avoid common gunsmithing mistakes that lead to loose parts, stripped threads, or difficult repairs. This quick guide arms both new and experienced builders with the knowledge to build safer, more reliable firearms that hold up over time.

Intro and vibration-related thread issues

Steve kicks things off by explaining how vibration is the enemy of fasteners. On firearms, particularly semi-automatic platforms like the AR-15, screws and bolts are constantly under stress. Without the right treatment, they’re bound to back out over time.

Low-strength threadlocker use cases

Caleb points out that low-strength threadlocker, usually purple, is ideal for small screws and parts that need to be removed frequently. He recommends it for things like optic screws, where you want holding power but also the ability to take things apart later without damage.

Better thread fit means less need for compounds

If threads are properly cut and fit, you may not need threadlocker at all. Steve explains that a precise mechanical fit combined with correct torque often eliminates the need for adhesives. It’s not always about more products—it’s about better assembly.

Risks of overtightening and stripped threads

Threadlocker isn’t a substitute for proper torque. Caleb reminds viewers that overtightening screws can easily strip out threads, especially in aluminum receivers. Always follow manufacturer torque specs and use torque tools when possible.

Medium threadlocker recommendations

The most commonly used threadlocker in gun work is the medium-strength blue variety. Caleb recommends it for securing scope mounts, base screws, and other parts that should stay put under recoil but can be removed later with hand tools.

Cleaning and degreasing before application

Before applying any threadlocker, it’s critical to clean and degrease the threads. Oil or debris can prevent the compound from curing properly. Steve suggests using denatured alcohol or a dedicated degreaser to prep the surfaces before applying any adhesive.

High-strength threadlocker and when to avoid it

Red threadlocker is considered high strength and should be used with caution. Caleb explains that it often requires heat to break loose, which can damage finishes or even parts. Avoid using red on anything you may need to service later.

High-temp ceramic compound for muzzle devices

For muzzle devices or suppressor mounts, Caleb introduces a ceramic-based high-temperature compound. It holds under extreme heat and pressure but isn’t as difficult to break loose as red threadlocker. It’s a smart choice for high-temp applications.

Why threadlocker is bad for gas block screws

Both Caleb and Steve strongly advise against using threadlocker on gas block screws. These parts are exposed to high temperatures and carbon fouling. Threadlocker may not hold, or worse, it may fail under heat. They suggest other options for securing gas blocks.

Pro tip on pinning your gas block

The preferred solution for securing a gas block, especially on hard-use rifles, is to pin it. A properly installed pin won’t back out under heat or vibration, and it offers long-term durability far beyond what threadlocker can provide.

Viewer comments welcome

Caleb wraps things up by encouraging viewers to share their experiences and ask questions in the comments. Whether you're a new builder or a seasoned gunsmith, the right application of threadlocker can improve the reliability and longevity of your firearm.

Using the correct type of threadlocker—and applying it properly—is a small step that can prevent big problems. From mounting optics to securing muzzle devices, understanding how each product works helps you build smarter and safer.

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