Question: what is the difference between blue and red loctite?
Answer: Permabond Blue Threadlocker MM115 is a Medium strength Medium viscosity threadlocker. Blue threadlockers are often called removable threadlockers as they can be disassembled with hand tools. Permabond Red Threadlockers HM118, HH120, HM128, HM129 and HH131 are all high strength threadlockers.