How Threadlockers Work
Threadlockers cure after assembly to create a solid polymer inside the threads, helping lock the fastener, seal micro-gaps, and reduce loosening under vibration.
-->
Suggested scene: liquid on bolt threads → assembly squeeze-out → oxygen excluded → cured layer fills gaps.
Curing process (4 steps)
-
1Apply liquid to threads
Dispense a small bead onto the male threads (and/or inside the nut for larger sizes).
-
2Assemble & distribute
As the fastener is tightened, the liquid spreads across engaged threads and gaps.
-
3Oxygen is excluded
Inside the joint, air is blocked; the adhesive is confined between metal surfaces.
-
4Cures & fills gaps
The adhesive polymerizes into a solid layer that helps lock, seal, and resist loosening.
LOCTITE Threadlockers are trusted worldwide to secure threaded fasteners against vibration, shock, and environmental stress.
They cure anaerobically to form a solid thermoset plastic between metal threads—eliminating loosening, sealing against corrosion, and ensuring long-term reliability in any industrial environment.
What Is a Threadlocker?
A threadlocker is a specialized anaerobic adhesive designed to lock and seal threaded fasteners.
When confined between metal surfaces and deprived of air, it cures to form a durable polymer that bonds the threads together, preventing loosening and leakage caused by vibration, impact, or thermal expansion.
Unlike mechanical locking devices such as lock washers or split pins, LOCTITE threadlockers create a 100% contact bond that resists even the most demanding conditions.
How Threadlockers Work?
LOCTITE Threadlockers fill the microscopic gaps between threads.
Once assembled, the absence of oxygen and the presence of active metal ions trigger the adhesive to cure.
The result: a tough, thermoset polymer that holds fasteners in place and protects against vibration, shock, and corrosion.
Curing process:
Liquid threadlocker is applied to the threads.
The fastener is assembled and tightened.
Air is excluded, curing begins.
A strong, durable bond forms—locking and sealing the joint.
Common Applications
LOCTITE Threadlockers are used across industries where safety, precision, and reliability matter most:
Automotive: engine bolts, transmission assemblies, brake components
Industrial equipment: pumps, compressors, gearboxes, motors
Aerospace and defense: critical vibration-resistant fasteners
Electronics: circuit board screws and miniature components
Maintenance & repair: reassembly of worn or vibrating machinery
Prevent costly downtime—once applied, your fasteners stay locked and sealed for the life of the assembly.
Why Choose LOCTITE Threadlockers?
LOCTITE invented the original anaerobic threadlocker technology—and remains the global standard today.
Compared to traditional mechanical locking methods, LOCTITE provides superior reliability and simplified assembly.
| Traditional Methods | LOCTITE Threadlocker |
|---|---|
| Lock washers loosen under vibration | Forms a 100% contact bond |
| Threads corrode or seize | Seals against moisture and contaminants |
| Uneven stress and fatigue | Distributes load evenly |
| Frequent retightening required | Maintenance-free for the product lifetime |
| Limited temperature resistance | Up to 230 °C, depending on grade |
Key Benefits
Prevents loosening due to vibration or impact
Protects against corrosion and leakage
Reduces need for re-tightening
Works on all metal fasteners and thread sizes
Simplifies inventory—one product replaces many mechanical devices
How to Choose the Right Threadlocker
Selecting the correct grade ensures proper performance and disassembly when needed:
| Requirement | Recommended Grade |
|---|---|
| Small screws / adjustable parts | LOCTITE 222 |
| General maintenance / medium bolts | LOCTITE 243 / 248 |
| Permanent assemblies | LOCTITE 262 / 263 |
| High temperature | LOCTITE 272 |
| Pre-assembled fasteners | LOCTITE 290 |
How to Apply Threadlocker
1. Prepare the threads
Clean with LOCTITE SF 7063 or an equivalent cleaner to remove oil and dirt.
2. Apply the adhesive
Apply a few drops to the bolt threads or into the nut.
3. Assemble and tighten
Tighten to the manufacturer’s torque specification. The adhesive spreads evenly as the fastener is tightened.
4. Allow to cure
Fixture time is typically a few minutes; full cure occurs in 24 hours at room temperature.
Use LOCTITE SF 7649 activator on inactive metals or at low temperatures.
5. Disassembly
Use standard hand tools for medium-strength grades.
For high-strength grades, heat the joint to ~250 °C before disassembly.
Easy to use
Effective anti-loosening
Heat resistant up to 220°C
Rust and corrosion resistant
Easy to disassemble
Reduces inventory costs
FAQs
Q1: Can LOCTITE Threadlocker be removed?
Yes—use heat or tools depending on grade. Medium-strength products can be removed with hand tools.
Q2: Does it work on stainless steel or plated parts?
Yes, but using a primer or activator improves curing on passive metals.
Q3: Can it fill gaps or worn threads?
Small gaps are filled effectively; for large clearances, use LOCTITE Retaining Compounds.
Q4: What’s the difference between 243 and 248?
Same medium strength—248 comes in a convenient stick form.
Q5: How long does it take to cure?
Fixture strength in 5–15 minutes; full cure in 24 hours.