Do you want red or blue Loctite?

You would think getting this wrong once would be lesson enough, but apparently, I needed a reminder as to which thread locker is which: blue is for parts that will need to come off again. Red is intended to be permanent.

Not using Loctite on one of my projects is a surefire way to ensure I find screws or bolts missing later. Using the wrong Loctite ends up in stripped threads and real trouble. Loctite offers this unmemorable rhyme: "Blue, easy to make new. Red, full strength ahead!" I am trying to remember that Red serves as a warning I'll need help to remove it.

What's the difference between red and blue Loctite threadlocker?

Loctite threadlockers are primarily designed to prevent fasteners from leaking or loosening from vibration. The difference between red and blue threadlocker is a matter of strength and removability. Loctite threadlocker blue is designed to easily be replaceable with common tools, whereas red is a more permanent fix. If you have trouble keeping it straight, here's a helpful rhyme to jog your memory: "Blue, easy to make new. Red, full strength ahead!"

For a hold that can be easily removed, Loctite Threadlocker Blue 242 is the hero. It's perfect for motorized and nonmotorized parts that need occasional servicing, like car parts (oil pans, water pumps, etc), or even motorized yard equipment, bicycles, furniture and much more.

For parts that need a more permanent hold, like structural bolts in a home, auto suspensions and frames, or any other heavy machinery, Loctite Threadlocker Red 271 is the answer. This industrial grade threadlocker packs a stronger punch than the blue and can only be removed by heating the parts to 500F.

Loctite

If you really hate reading:

Remember: Loctite makes a myriad of other things as well. Do not mistake super glue for threadlocker.

Previously:
These guys tested which construction adhesives work best