Searching for "lock tight"? You're looking for Loctite, the threadlocker brand from Henkel. Loctite threadlockers are color-coded by strength: purple is low, blue is medium, red is high, and green is a wicking grade for parts that are already assembled. Pick the wrong color and you either get a bolt that vibrates loose or one you can't get off without a torch. This guide shows which Loctite to use, how to apply it, and how to remove it. Loctite Threadlocker Color Chart Color Strength Common g …