Loctite Medium Strength Blue Threadlocker 242, 250 mL Bottle — Removable, Vibration-Resistant

Loctite 24241 Blue is a medium-strength anaerobic threadlocker in a 250 mL bottle designed to lock and seal threaded fasteners while still allowing removal with hand tools.

This liquid threadlocker from Loctite (Series 242) cures without air between metal threads to prevent loosening from vibration, seal against leakage and protect against corrosion. Supplied in a 250 mL bottle, the formula is blue, has medium bonding strength, and is engineered for fasteners with diameters from 1/4" (6 mm) up to 3/4" (19 mm). It offers a practical balance of holding power and serviceability: assembled joints resist vibration but can still be disassembled using common tools when maintenance is needed.

How quickly does this threadlocker set and fully cure?

Initial handling strength develops in minutes, with cure speed depending on the metal contact area and environmental conditions. Typical handling time is about 10 minutes and a full cure is achieved in approximately 24 hours under normal conditions.

• Initial set: ~10 minutes
• Full cure: ~24 hours
• Best cure where metal-to-metal contact is consistent and air is excluded

What fastener sizes and gaps is Loctite 242 suitable for?

Formulated for a wide range of common fasteners, this medium-strength threadlocker is optimized for bolts and screws from roughly 1/4" to 3/4" in diameter. It handles small thread clearances; gap fill capability is about 0.005 inches, so it works best on properly fitting threads rather than large, loose joints.

• Recommended fastener diameter: 1/4" to 3/4" (6–19 mm)
• Gap fill: approximately 0.005 in (0.13 mm)
• Not intended for large voids or heavily corroded threads

What temperature and chemical properties affect performance?

The cured adhesive remains stable across a broad working range, performing in environments from very cold to high heat. It is an anaerobic, liquid formulation with measurable viscosity and a flash point above 93.3°C for safer storage and handling.

• Operating temperature range: -65°F to 300°F (-54°C to 149°C)
• Specific gravity: ~1.1; viscosity: 1200–5000 cP
• Flash point: >93.3°C; chemical type: anaerobic

How do I remove fasteners if I need to service or replace them?

Because this is a medium-strength formulation, joints are serviceable and can be taken apart with standard hand tools or controlled heating if required. The product is designed to allow removal without damaging threads when proper techniques are used.

• Removable with hand tools under normal conditions
• Applying heat or penetrating tools can aid stubborn joints
• Avoid prolonged exposure to extreme heat that could alter properties

Who is this for: Loctite 24241 Blue 250 mL is intended for mechanics, maintenance technicians, builders, and hobbyists who need a reliable medium-strength threadlocker for machinery, automotive assemblies, household repairs and industrial equipment. Manufactured in the United States, it suits applications that demand vibration resistance and a balance between permanent locking and future disassembly.

• Adhesives & Sealants
• Country of manufacture: United States
• Manufacturer: Loctite