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

Loctite 242 Blue is a medium-strength anaerobic threadlocker in a 250 mL bottle designed to lock and seal threaded fasteners from 1/4" to 3/4" while remaining serviceable with standard hand tools.

Engineered for general-purpose industrial and maintenance applications, this Loctite 242 Medium Strength Threadlocker cures in the absence of air and on metal surfaces to prevent loosening from vibration and leakage from fluid exposure. The blue formulation balances secure locking with disassembly capability, fully curing in about 24 hours and offering operating performance from -65°F up to 300°F. Supplied as a liquid in a 250 mL bottle, it has a viscosity range of 1200–5000 cP and fills gaps up to 0.005 inches.

How quickly will Loctite 242 set and when is it fully cured?

Initial handling strength develops within approximately 10 minutes after application, allowing assemblies to be handled. Full cure typically completes in 24 hours under normal conditions, though cure speed depends on metal contact area and temperature.

• Initial handling time: ~10 minutes
• Full cure time: ~24 hours
• Cures anaerobically—requires confined metal surfaces and absence of air
• Faster cures on larger metal contact areas and at warmer temperatures

What range of fastener sizes and environments is this threadlocker suitable for?

Loctite 242 is formulated for fasteners with diameters from 1/4" to 3/4", providing medium-strength locking for bolts, nuts, studs and similar hardware. Its operating temperature span makes it suitable for many indoor and moderate-temperature outdoor applications.

• Fastener diameter suitability: 1/4" to 3/4"
• Service temperature range: -65°F to 300°F
• Gap-filling capability: up to 0.005 inches
• Removable with standard hand tools when disassembly is required

What are the physical and handling properties I should know?

The product is an anaerobic liquid with a specific gravity of about 1.1 and a viscosity between 1200 and 5000 cP, making it easy to apply from a bottle while staying in place on threads. It has a flash point over 93.3°C and is manufactured in the United States by Loctite for consistent quality.

• Physical form: liquid in 250 mL bottle
• Viscosity: 1200–5000 cP for controlled flow
• Flash point: >93.3°C for storage and safety considerations
• Made in the United States by Loctite (Henkel brand)

How do I remove or replace fasteners treated with Loctite 242?

Because this is a medium-strength threadlocker, treated fasteners can be disassembled with conventional hand tools. If a stronger bond or damaged threads are encountered, heat or dedicated threadlocker removers can assist removal.

• Removable using hand tools for typical maintenance tasks
• Extra assistance: controlled heat or chemical removers if needed
• Always allow sufficient cure time before applying disassembly torque
• Inspect threads for damage before reuse

Who is this for? Loctite 242 Blue Medium Strength Threadlocker suits technicians, maintenance crews, mechanics, fabricators and DIYers who need a reliable, removable locking solution for machinery, automotive assemblies, HVAC components and general equipment. It’s ideal when you want dependable vibration resistance and fluid sealing but also need the option to service or replace parts using standard tools.