How Threadlocker Works

Threadlocker is an anaerobic adhesive — it cures in the absence of air, in the presence of metal ions. Apply it to clean threads, assemble the joint, and the liquid wicks into the gaps and hardens.

Blue (Loctite 242 / 243) is removable with hand tools — use it on bolts you'll service.

Red (Loctite 271 / 272) is permanent and typically requires heat to break — use it on bolts that absolutely cannot come loose.

Always degrease threads before applying. Oil and cutting fluid will keep threadlocker from curing.