Loctite 242 vs 222: Which Threadlocker Should You Choose?
Loctite 242 is a medium-strength blue threadlocker rated for 1/4″ to 3/4″ bolts; Loctite 222 is a low-strength purple formula designed for small screws up to 1/4″.
Garage pros grab the familiar blue bottle for suspension bolts, then panic when tiny eyeglass screws snap off. That’s why the purple label gets overlooked—until a costly mistake teaches the difference.
Key Differences
242 cures to 180 in-lb breakaway torque, removable with hand tools; 222 yields just 55 in-lb and comes off with a jeweler’s screwdriver. Temperature ceiling: 300 °F vs 300 °F, yet chemical resistance favors 242.
Which One Should You Choose?
Use 242 on lawnmower blades, brake calipers, mountain-bike crank bolts. Reserve 222 for electronics, RC cars, or scope rings—places where future micro-adjustments matter more than brute holding power.
Can I use 242 on my laptop screws?
Yes, but you’ll risk snapping the tiny threads; stick to 222.
Is purple Loctite weaker than nothing at all?
No—55 in-lb beats vibration, yet yields easily when you need it gone.