LOCTITE® 243 Blue Medium Strength Threadlocker

Features and Benefits

LOCTITE 243 is a medium strength blue threadlocking adhesive that seals and secures metal nuts and bolts to prevent loosening due to shock and vibration.
LOCTITE® 243 is a general purpose threadlocker that provides a medium strength bond. LOCTITE 243 works on all metals, including passive substrates such as stainless steel, aluminum and plated surfaces. It is proven to be tolerant of minor contamination due to industrial oils, e.g., motor oils, corrosion prevention oils and cutting fluid.
  • Prevents loosening on vibrating assemblies, e.g. pumps, gear boxes or presses
  • Works on all metals, including passive substrates (e.g. stainless steel, aluminum, plated surfaces)
  • Proven to tolerate minor contamination by industrial oils, e.g. motor oils, corrosion prevention oils and cutting fluids
  • Permits disassembly with hand tools for servicing
  • P1 NSF Reg. No.: 123000
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Technical Information

Application method Dispense Gun, Dispense System, Manual
Application temperature -55.0 - 180.0 °C (-65.0 - 360.0 °F )
Applications Threadlocking
Breakaway torque, M10 Steel Nuts/Bolts ~26.0 N·m (230.0 in./lb. )
Color Blue
Cure type Anaerobic Cure
Fixture time 10.0 min.
Key characteristics Disassembly: Removable, Fluorescent, General Purpose, Oil Tolerant, Primerless, Strength: Medium Strength, Thixotropic
Physical form Liquid
Prevail torque, M10 Steel Nuts/Bolts 5.0 N·m (40.0 in./lb. )
Recommended for use with Metal, Metal: Passive Metal
Specific gravity, @ 23.0 °C 1.08
Viscosity, Speed 20 RPM 2150.0 mPa·s (cP)

How to

Step by Step Guide

1. Preparation - Cleaning

It is recommended to use LOCTITE® SF 7063, SF 7064, or SF 7070 to degrease and clean surfaces prior to applying threadlocker adhesive.

2. Preparation - Activation

If cure speed is too slow due to passive metals (stainless steel, aluminum and plated metals) or low temperature (below 5°C), use activator LOCTITE SF 7240 or LOCTITE SF 7649 (see cure speed vs activator graph in the TDS).

3. Application

Apply liquid threadlocker to the engagement area. For manual dispensing, the use of a peristaltic handgun or the LOCTITE® Pro Pump is recommended to ensure a consistent application volume.

4. Application - Through Hole

Insert bolt and apply threadlocker to the exposed thread. Assemble nut and tighten to the correct/specified torque.

5. Application - Blind Hole

Apply several drops of liquid threadlocker down the sides of the blind hole filling the lower third. Apply several drops to the bolt.

6. Assembly

Assemble and tighten. If several bolts are being assembled, torque them down to the correct value within the fixture.

7. Disassembly - Hand Tools

Disassemble with standard hand tools.


For the disassembly of corroded or seized parts use LOCTITE® LB 8040 Freeze and Release.

Frequently Asked Questions