Question: How do I disassemble nuts and bolts that have been assembled using anaerobic threadlockers, and then re-use the fasteners?
Answer: The problem in doing this is that the threadlockers are designed to be resistant to extreme operating conditions, such as high heat and immersion in aggressive solvents and fluids. In addition, they have high adhesive strengths, which prevent vibration loosening of the fasteners.
Threadlockers are generally of three common types. A low-strength version, which is intended for small screws, is usually purple in color from most manufacturers. A blue medium-strength version, the most widely used threadlocker, is designed for fairly high strengths on assemblies that might need disassembly for maintenance or repair. Lastly, a red version offers very high strength and is designed for permanent assemblies that would normally not be disassembled.
The low-strength version is very easy to disassemble, and the medium strength can usually be removed with normal tools. However, should it be necessary to disassemble assemblies using the high-strength threadlocker, this is more of a challenge. The secret to doing this is to destroy the adhesion between the threadlocker and the fastener with high heat. Once this initial bond is broken, the prevailing torque from the cured anaerobic will not prevent disassembly. Use a blow torch or other heating method to heat the assembly to 400-500ºF and disassemble while hot. If you want to reuse the fasteners, apply more threadlocker before assembly. However, for best results, the residue of the cured material can be removed. Either burn it off with a blowtorch or soak it in an aggressive solvent to soften it and then use a wire brush. Methylene chloride (which I call “old-fashioned paint remover”) is the best solvent for this.
Any views or opinions expressed in this column are those of the author and do not represent those of ASI, its staff, Editorial Advisory Board or BNP Media.
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