What are Threadlockers?

What are Threadlockers?

What are threadlockers? Lockfast threadlockers are anaerobic adhesives used to lock threaded fasteners.



What has exercise got to do with it?

Absolutely nothing! Exercise is commonly associated with the term aerobic (with oxygen). Anaerobic means without oxygen, which is the opposite of aerobic. Anaerobic adhesives cure via a free-radical process, and they will not cure in the presence of air. The reaction begins with metal ions present, followed by air being locked out. As a result, it is well suited for locking threaded fasteners such as nuts and bolts.

Reactive chemistry

Since anaerobic adhesives are 100% reactive, their initial fixing time can vary depending on the substrate. As a result of the presence of more metal ions, more reactive substrates, such as copper, brass, bronze, iron, and mild steel, can be fixed in a shorter period, compared to “passive” substrates such as stainless steel, aluminium, galvanized, zinc phosphate, silver, oxide films, chromate finishes, anodic coatings, plastics, and ceramics. They may take longer to fix, but they are still fast. It is always within 24 hours that ultimate strength is reached.

Fixture time vs substrate reactivity graph

Fixture time vs substrate reactivity graph

(The graph depicted above is not scientific and is for illustrative purposes only.)

Why is the bottle only half full?

To inhibit the reactive curing process, threadlockers are stored and packaged with air. Because half of the bottle contains air, and the other half contains thread locker, it may look like the bottle is underfilled, but Lockfast is packaged in larger bottles to allow for this so a 10ml thread locker is packaged in a 20ml bottle. Air can also penetrate the bottle because it is made from LDPE (low-density polyethylene), which can help preserve the products shelf life.

Thread Locker Inside the Bottle - Illustrated.

Threadlocker Inside the Bottle – Illustrated.

Why choose anaerobic adhesives over mechanical methods?

As Lockfast anaerobic threadlockers replace the need to hold a variety of types and sizes of traditional fasteners, such as lock washers, split pins, and nylon lock nuts, holding a few grades can be less expensive. There is only a need for a few drops per application (depending on thread size).

Thread Locker application - Illustrated.

Thread Locker application – Illustrated.


What are the physical benefits?

Lockfast threadlockers cure in the joint, so they are clean and easy to use. By filling the gap between the mating threads, they provide vibration-proofing and shock resistance, as well as preventing leaks and galvanic corrosion. UV light can also be used to identify most products.




Threaded fastener vs thread locker gap fill - Illustrated.

Threaded fastener vs threadlocker gap fill – Illustrated.


Breakaway and prevailing torque

Two indicators of strength are breakaway and prevail, both measured in Newton-metres (Nm). It is the breakaway force that causes the bond to break, and it is the prevailing torque that causes the thread to unscrew. Higher strength threadlockers (STUDLOCK) will typically have a higher prevail than breakaway strength.

Thread locking grades explained

There are three main categories in the Lockfast range.


A low strength threadlocker that can be disassembled with hand tools.

These are also more suited to weaker metals to prevent substrate failure.


Are medium strength threadlockers.


Are high strength threadlockers.

Lockfast Thread Lockers Strengths

Lockfast Threadlockers Strength Categories.

These are also colour coded, green, or red typically represents a higher strength product, blue medium or medium to high, and purple low.


For further technical information or if you have a different question please contact us.

Published by Matthew Cox – 06/09/2022

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