In many industrial settings, keeping threaded fasteners secure is more challenging than it first appears. Machinery assembly, maintenance, and repair often take place in environments where oil, grease, or cutting fluids are present on metal surfaces. While these lubricants are essential for equipment operation, they can seriously compromise the performance of traditional threadlocking solutions. This is where LOCTITE 243, a medium-strength, oil-tolerant threadlocker, has become a trusted choice for engineers and maintenance professionals worldwide.
This article explains how LOCTITE 243 improves fastener reliability in oily environments, what makes its technology different, and why it is widely used across manufacturing, maintenance, and industrial assembly applications.
The Challenge of Threadlocking in Oily Conditions
Threaded fasteners are exposed to vibration, thermal cycling, and dynamic loads during operation. Without proper threadlocking, bolts and nuts can loosen over time, leading to:
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Equipment failure
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Increased maintenance downtime
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Safety risks
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Higher repair costs
In ideal conditions, fasteners are cleaned thoroughly before applying a threadlocker. However, in real-world production and maintenance environments, complete degreasing is not always practical or economical. Oil residue on metal threads can prevent many threadlockers from curing properly, resulting in reduced bond strength and unreliable performance.
An effective solution must be able to cure and perform even in the presence of oil—without adding extra preparation steps.
What Is LOCTITE 243?
LOCTITE 243 is a medium-strength anaerobic threadlocker designed specifically to deliver reliable performance on metal fasteners, including those with light oil contamination. It belongs to the threadlocker product category and is based on acrylate technology with anaerobic cure.
Key product characteristics include:
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Oil tolerant formulation
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Primerless curing on active and passive metals
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Removable (medium strength) performance
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Fluorescent for inspection and quality control
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Thixotropic liquid to prevent dripping or migration
These features make LOCTITE 243 suitable for both production lines and maintenance operations.
How Anaerobic Cure Technology Works
LOCTITE 243 cures through an anaerobic reaction, meaning it hardens when air is excluded and the adhesive is confined between metal surfaces. Once applied to a bolt or nut and assembled, oxygen is displaced, and the adhesive polymerizes to form a strong, durable bond.
This curing mechanism provides several advantages:
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No curing until parts are assembled
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Uniform curing throughout the thread engagement
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Resistance to vibration and shock
Importantly, LOCTITE 243 is engineered to cure even when light oil is present, which is a critical advantage over conventional threadlockers.
Reliable Performance on Oily Fasteners
Oil Tolerance Without Compromising Strength
One of the defining advantages of LOCTITE 243 is its ability to tolerate oil on fastener surfaces. In many applications, fasteners are pre-lubricated to prevent corrosion or are exposed to oils during machining and assembly.
LOCTITE 243 maintains consistent performance on lightly contaminated threads, helping to:
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Reduce preparation time
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Eliminate the need for aggressive cleaning
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Improve consistency in real-world conditions
This makes it particularly valuable in maintenance, repair, and overhaul operations, where fasteners are rarely perfectly clean.
Consistent Torque Performance
Fastener reliability is often measured by torque values. LOCTITE 243 delivers balanced performance with:
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Breakaway torque (M10 steel): ~26 N·m
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Prevail torque (M10 steel): ~5 N·m
This medium-strength profile ensures that fasteners remain secure during operation but can still be disassembled using standard hand tools when maintenance is required.
Designed for Practical Assembly and Maintenance
Fast Fixture Time
With a fixture time of approximately 10 minutes, LOCTITE 243 supports efficient workflows. Assemblies can be handled or lightly loaded shortly after installation, helping to maintain productivity on the shop floor.
Wide Operating Temperature Range
Industrial equipment often operates under varying thermal conditions. LOCTITE 243 performs reliably across a broad temperature range, from -55 °C to 180 °C, ensuring stability in both cold starts and high-temperature operating environments.
Thixotropic Liquid for Controlled Application
As a thixotropic liquid, LOCTITE 243 stays where it is applied. This prevents adhesive from running or migrating into unwanted areas, which is especially important in precision assemblies or vertical applications.
It can be applied using:
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Manual application
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Dispense guns
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Automated dispensing systems
This flexibility makes it suitable for both small-scale repairs and high-volume production lines.
Improved Reliability Means Lower Maintenance Costs
Fastener loosening is a hidden cost driver in industrial operations. Every loose bolt can result in:
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Unplanned downtime
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Additional inspections
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Component wear or damage
By ensuring consistent locking performance—even on oily fasteners—LOCTITE 243 helps reduce these risks. Over time, this leads to:
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Fewer maintenance interventions
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Longer equipment service intervals
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Improved operational safety
The result is a more reliable fastening system without added process complexity.
Applications Across Industries
LOCTITE 243 is widely used in industries where oil exposure is common, including:
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Industrial machinery assembly
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Automotive and transportation equipment
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Pumps, motors, and gearboxes
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Maintenance and repair operations
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General metal fastening applications
Its compatibility with active and passive metals further expands its range of use.
Quality and Support from Wuhan Hualiwei New Material Co., Ltd.
As a trusted supplier of advanced adhesive solutions, Wuhan Hualiwei New Material Co., Ltd. is committed to delivering reliable, eco-friendly products that meet the needs of modern industries. The company focuses on low-carbon adhesive technologies and provides customized bonding solutions for industrial, pharmaceutical, and hygiene applications.
All products undergo rigorous testing and comply with international standards such as ISO 9001, REACH, and FDA requirements, ensuring consistent performance, safety, and environmental responsibility. In addition to supplying high-performance products, the technical team offers one-on-one support, from formulation optimization to on-site production guidance.
For detailed technical information about LOCTITE 243 and its applications, visit:
https://www.hlw-adhesive.com/loctite-243-threadlocker-medium-strength-oil-tolerant-for-metal-fasteners.html
Conclusion
In real industrial environments, perfect conditions are rare. Oil contamination on fasteners is common, and fastening solutions must be designed to perform reliably under these conditions. LOCTITE 243 addresses this challenge through its oil-tolerant, anaerobic curing technology, delivering secure, medium-strength threadlocking without adding complexity to assembly or maintenance processes.
By improving fastener reliability, reducing loosening, and lowering long-term maintenance demands, LOCTITE 243 remains a practical and proven choice for engineers and technicians seeking dependable performance in oily environments.
www.hlw-adhesive.com
Wuhan Hualiwei New Material Co., Ltd.
