[Scooby Steve]

The blue is semi-permanent. Also found this by using Search:

Originally Posted by Darklen

Sounds like locktite 222. I use many locktites on a daily basis for breathing air equipment (aka Scott packs). While I don't use the 262 mentioned above, we use:

222 - milky purple in color, low strength, for when you don't want the screws to vibrate out on their own

242 - milky blue in color, high test version of 222. takes a bit more to remove so use it in more high vibration situations or where more strength is needed

271 - clear red, high strength thread lock. basically use where you never want to take it apart again.

One thing I don't see mentioned, and maybe I'm one of the few that comes across this, is do not use locktite thread retaining or locking compounds on plastic parts. It doesn't melt or craze them but it does weaken the plastic over time, causing it to crack. So if your using say 242 to secure your grip into your new AR gearbox, put the screws on a paper towel or tissue and put a small drop of locktite on the screw. Allow the excess locktite to be absorbed into the towel, then screw int the gearbox. Remember, locktite is a retaining/locking compound, not stickum glue. A little goes a very long way.

Edit: LOL you're fast Darklen.