Mechanical locking devices (such as split ring washers, nylon insert nuts, and serrated tooth washers were invented to solve the common problem of loosening that happens in most threaded assemblies). However, the reality is that they don’t “lock” the assemblies and can’t maintain clamp load. These devices often loosen under vibration, thermal expansion, bending, and/or improper torque.

Threadlockers, or threadlocking adhesives, are the solution to this problem. Applied between two mating threads, these liquid threadlocker adhesives secure nuts, bolts, and threaded fasteners in place. They cure to form a strong bond that prevents loosening, ensuring assemblies retain clamp load over time.

Threaded fasteners, such as bolts and nuts, have a huge role to play in many industries. Their impressive clamp load means they are the ideal fastener for use across a wide range of manufacturing and maintenance applications. However, these types of assemblies can fail over time as they work themselves loose, thanks to vibration, bending, or thermal expansion.

Choose from a range of different strengths and application types and discover LOCTITE® threadlockers that:

  • Reduce downtime
  • Provide strong, long-lasting adhesive performance
  • Reduce the risk of loosening and leaks
  • Lower maintenance and manufacturing costs

Contact a member of our team today to find out more about our LOCTITE® threadlocker solutions.

To find out more about our LOCTITE® services and support, you can request a free LOCTITE® Consultation.

Benefits of LOCTITE® Threadlockers

LOCTITE® threadlockers are products you can trust for securing threaded fasteners in place. An industry-leading solution for more than half a century, they offer versatility, affordability, and reliability in your assemblies.

Threadlocking compounds can effectively reduce the impact of costly failures, repairs, maintenance, and downtime. Applied to one or two threads before assembly, LOCTITE® threadlockers push the air between the threads out as the fastener is tightened. The anaerobic threadlocker material cures in the absence of air to form a strong, thermoset plastic that locks threads and joints in place.

LOCTITE® threadlockers can also lower the effect of corrosion in threaded components and help to prevent leaks in your assemblies. Applicable across both maintenance, repair, and operations (MRO) and original equipment manufacturing (OEM), LOCTITE® threadlockers improve reliability, eliminate failure, and boost productivity in your operations.

Our threadlockers are single-component liquid adhesives that secure nuts, bolts, and threaded fasteners. They are designed to eliminate air gaps that, combined with vibration and shock, that allow for loosening in threads. This is achieved by forming a strong bond between the threads that holds everything tightly in place with a controlled strength thread lock.

All LOCTITE® threadlockers have a broad temperature resistance of -65°F to 300°F, while some threadlockers are designed for high temperatures up to 650°F. Threadlockers were LOCTITE®’s first product line. They combine a mix of complex chemistry and engineering. Simply put, this product is an anaerobic adhesive applied by drops to the threads of fasteners. It then cures to a hard thermoset plastic that locks the threads together. They are used only for metal-to-metal applications.

Choosing a LOCTITE® Threadlocker

Our products are available in many different grades to cater to a broad array of applications, from auto maintenance and boat maintenance to a wide range of household repairs. These different grades or thread lock types are color-coded to help you distinguish one threadlocker type from another. Our user guide contains a threadlocker chart that details the properties of each product. The color refers to the actual substance, but all the bottles are red in color. The red bottle is actually a LOCTITE® trademark. It’s what visually distinguishes LOCTITE® threadlockers from any other brand.

Choosing between a LOCTITE® red, blue, green, or purple threadlocker will depend on the specific needs of your project and the threadlocker strength you require. To find the right threadlocker for your task, key considerations should include:

  • Maintenance and disassembly needs
  • Temperature requirements of application
  • Application strength and vibration levels
  • Type of assembly
  • Thread size
  • Application area and location

Differences between Threadlocker Grades

LOCTITE® Red Threadlocker

LOCTITE® red threadlocker is the highest strength of threadlocker adhesive. This product cures fully in 24 hours and is available in both a liquid and as a semisolid anaerobic. The red high strength threadlocker products are so powerful they may require heat to be disassembled. A primerless grade red threadlocker is also available.

LOCTITE® Blue Threadlocker

LOCTITE® blue threadlocker is medium strength threadlocker adhesive. This product cures fully in 24 hours and can be disassembled with hand tools. Blue threadlockers are removable with standard hand tools on 6mm to 20mm fasteners, have fast fixture times, and are available in liquid, stick, paste and gel form. Moreover, there is also LOCTITE® QuickTape 249™ Threadlocker, the one and only of its kind globally. A primerless grade blue threadlocker is available as well. 

LOCTITE® Green Threadlocker

LOCTITE® green threadlocker is recommended for locking preassembled fasteners, e.g. electrical connectors and set screws, and prevents against loosening, rust, and corrosion. This wicking grade threadlocker is categorized as a medium-to-high-strength adhesive. Also available in a liquid form, LOCTITE® green wicking threadlocker cures in 24 hours and can be removed with hand tools and, in rare instances, may require heat to assist when threads have excessive engagement lengths.

LOCTITE® Purple Threadlocker

LOCTITE® purple threadlocker, also known as LOCTITE® 222™, has become one of our most successful products. LOCTITE® 222™ cures in 24 hours. This low strength threadlocker can be used on metals such as aluminum and brass and offers a lot of flexibility to the user.

LOCTITE® purple threadlocker has many uses, from carburetor screws to eyeglasses to small screws on laptops. Due to the threadlocker being low strength, it can be removed with the same tool used to put the project together. It is available in an easy-to-use liquid application, which makes the product especially efficient with very small screw applications, less than ¼ inches in diameter.

Compare Featured LOCTITE® Threadlockers

Find a solution for your application, from a permanent threadlocker for strong, long-lasting bonds in OEM applications, to removable products that allow for effective MRO strategies, with the range of LOCTITE® threadlockers: 


Discover the full range of threadlockers and download product specific technical data sheets (TDS), restriction of hazardous substances sheets (RoHS), and safety data sheets (SDS).

How to Apply Threadlockers

Depending on the assembly application, different forms of threadlockers can be used. The most common type are liquid threadlockers. However, threadlocker pastes, sticks, and tapes are also available. For overhead and pre-dispensed applications, threadlocker sticks and tapes are an easy and mess free way to apply threadlocker and provide the same excellent performance properties as our range of liquid threadlockers. LOCTITE® threadlocker pastes are packaged in convenient-to-use syringes and suitable for temperatures up to 650° F.

Our range of LOCTITE® threadlockers are easy to apply and use across your applications. However, for best results, follow our step-by-step guide to using threadlocking adhesives.

  1. Prepare both threads by cleaning to remove contaminants.
  2. Dry the threads fully before use.
  3. Apply a few drops of threadlocker to the thread.
  4. Slowly turn the nut to lock the fastener in place.
  5. Allow the threadlocker its full cure time (according to the technical data sheet (TDS)) before use.

For more information on threadlocker best practice, check out our in-depth threadlocker application guide.

Threadlocker Applications

Threadlockers can be used for a wide range of applications. For small fastener applications, a low strength threadlocker for small screws is the ideal solution. These are also an excellent type of threadlocker to use for aluminum, brass, and other low strength metal applications.

When it comes to automotive applications, it is important to use a threadlocker than can be removed using hand tools. While threadlockers are typically used for metal-to-metal applications, we have developed threadlockers designed for plastic-to-plastic and plastic-to-metal applications. It is important to note that threadlockers should not be used for wood-to-metal applications.

Find a LOCTITE® threadlocker for fittings of all shapes and sizes. As liquid adhesives, threadlockers are effective and suitable for any threaded application, including:

  • Through holes
  • Blind holes
  • Post-assembly
  • Overhead applications
  • Pre-applied applications

You can successfully deploy threadlocking adhesives to tackle any task, from improving the reliability of threaded fasteners in everyday applications, to ensuring strong bonds in industrial settings where failure is not an option.


How to Secure Threaded Assemblies

Threaded assemblies are present in most machines. Learn how they work and how to get your threads secured with LOCTITE®XPLORE, our new e-learning platform for Assembly, Maintenance and Vehicle Repair professionals.

Threadlocker FAQs

Further Resources

Learn how to effectively increase your threaded assemblies’ strength and reliability with threadlockers. Download our threadlocker MSDS and user guide below, or discover more about the LOCTITE® range of products with the threadlocker flyer and manual.


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Purple, red or blue? How to Choose a LOCTITE® Threadlocker

There are 3 things to consider when choosing a threadlocker and color is key, as it represents strength:

1. Strength

  •     Low strength (purple) - regular disassembly required
  •     Medium strength (blue) - suitable for most of the applications
  •     High strength (red) - disassembly only exceptionally necessary

2. Fastener Size

  •     From < ¼” (6 mm) fasteners on up, there’s a LOCTITE threadlocker

3. Application Methods

  •     Pre-Assembly: Most LOCTITE® liquid threadlockers are designed to be applied at the moment parts are assembled
  •     Post-Assembly: Wicking grade formula can be applied on parts that are already assembled


Learn More

Want to start making your equipment and end-product more reliable? Download the e-book to find out. Also consult the productflyer. 

LOCTITE Threadlocker Productflyer


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