For as long as there have been threaded fasteners, there have been challenges with ensuring they stay tightly locked and resist the self-loosening that can lead to costly failures and downtime.

That’s where threadlockers, or threadlocking adhesives, come into play. They eliminate the potential of loosening, leakage and failure by locking your fasteners in place. 

Successful application starts with knowing how to choose the right threadlocker for the task. There are various options in the LOCTITE® threadlocker range. Each has its own qualities and ideal application, so choosing the right one is important to ensure reliability in your assembly. 

Using the wrong type of threadlocker could lead to reduced reliability, difficulties with removal and improper curing. This may impact how well your adhesive locks assemblies in place, increasing the chance of loosening and failure.

Find out more about how to choose what threadlocker to use below, along with the key factors that determine which of the different threadlocker types is best for you, with our LOCTITE® threadlocker selection guide.

1. Need for Maintenance and Repair

You can rely on all LOCTITE® threadlockers to stay securely in place after application. But there are some assemblies where permanence isn’t required or could even be problematic. Maintenance, checks and repairs can mean there’s often a need to remove threadlockers to disassemble parts.

If you know which threadlocker to use, you can get the best of both worlds.  

The ease with which a threadlocker can be removed depends on its strength. 

  • Low and medium-strength threadlockers can be removed with standard hand tools.
  • High or permanent-strength threadlockers may require direct, intense heat application to disassemble.

For assemblies requiring regular maintenance and repair, low and medium-strength purple or blue threadlockers are the best choice. You should also choose these products for applications where heat could cause distortion or damage to sensitive materials, such as some plastics and elastomers.  

These threadlockers are easily removed with hand tools, which makes maintenance, repair and other ongoing work more efficient and safer, without compromising bond strength.

2. Use in High Heat Applications

Heat is one of the major factors that can impact the security and performance of any fastener. LOCTITE® threadlockers have a broad temperature resistance of -65°F to 300°F (-54°C to 149°C), making them suitable for use in most applications.

However, for applications where high temperatures are commonplace, choose a threadlocker with higher heat resistance, such as LOCTITE® 263. 

Using a product designed to withstand intense environmental conditions, such as high temperatures, means less chance of loosening in the thread. 

Our range of threadlockers is comprised of adhesives built to perform in any condition, including products that continue to operate efficiently in temperatures as high as 650°F (343°C).

3. Application Strength

In most applications, from heavy duty machinery to vehicle manufacturing, threaded assemblies are exposed to vibration and torque. 

For applications with a high risk of vibration or shock, choose red threadlockers. As the strongest grade of threadlocking adhesive, these provide the highest level of resistance to vibration, shock and torque. They hold firmly in place as a permanent solution. 

Our range of threadlocker strengths include:

  • LOCTITE® 222 – A low-strength purple threadlocker. Works on all metals and is especially good for applications that may require disassembly.
  • LOCTITE® 243 – A medium-strength blue threadlocker that offers a good general-purpose solution to seal and secure assemblies. 
  • LOCTITE® 263 – A high-strength red threadlocker designed for permanent locking and sealing of threaded fasteners. 

4. Assembly Type

The majority of threadlockers are designed to be used in fasteners at the point of application. In these cases, the adhesive is applied to the thread just before the fastener, locking it in place thereafter. 

This is ideal for use in manufacturing and maintenance of machinery. To choose the right LOCTITE® threadlocker, you can opt for either medium or high-strength options. 

In some preassembled applications, however, you’ll need to lock a thread after the fastener is in place. This can include electrical connectors and set screws.

Here, you need a wicking grade threadlocker that can work its way into the gaps between two bonded surfaces without the need for disassembly. Our green threadlockers, including LOCTITE® 290, are wicking grade, medium-strength threadlockers.

5. Thread Size

Before you choose your ideal LOCTITE® threadlocker, you need to consider the size of the thread. Getting it wrong can make servicing or disassembly more difficult.

Using a high-strength threadlocker, for example, in smaller thread sizes, can make it more difficult to remove the fastener without damaging the screw. On the other hand, using a low-strength threadlocker on a larger thread size can reduce the effectiveness of the adhesive.

Generally speaking, the larger your thread, the higher the strength your threadlocker needs to be. For example:

  • Small thread – LOCTITE® 222 is suitable for small threads up to a maximum size of M12.
  • Medium thread – LOCTITE® 243 seals and secures fasteners with a maximum thread size of M18.
  • Large thread – LOCTITE® 263 can be used with applications that have a thread size up to M20.

6. Application Area

When you need to apply a threadlocking adhesive overhead, regular products can drip down before they cure in place. One solution is to use a LOCTITE® stick, which has all the adhesive capabilities of other threadlockers, but comes in a semi-solid stick format. 

If you keep threadlockers in a toolbox for regular maintenance, a stick also prevents leakage, which can occur with liquid products. 

For overhead and other applications where dripping may be a challenge, there are various LOCTITE® sticks available, including: 

  • LOCTITE® 248 – The same performance as LOCTITE® 243 but in stick form, this is a blue, medium-strength threadlocking adhesive that works on all metals.
  • LOCTITE® 268 – A high-strength threadlocker stick suitable for applications requiring a stronger bond, though needs heating to 480°F (250°C) for disassembly.

Non-traditional Applications

If you require a threadlocker for non-traditional purposes, large scale use or a specific application, you may need a less standard option. 

Contact our Technical Information Services (TIS) for more information or get in touch with your local sales engineer to find the best threadlocker for your needs.

Explore the full range of LOCTITE® threadlockers to find the right threadlocker for any threaded fastener application, or find out more about the different types of threadlocker and their qualities.

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