I cannot get an assembly apart where a threadlocker was used. What solvent will break the threadlocker down?
No solvent will wick into the joint to break the threadlocker down. This is either hand tool removable at room temperature or if not, it requires high temperatures of 450-600°F to separate parts. The products are thermoset plastics in the cured state that soften at higher temperatures. Thus, you need to disassemble while at the higher softening point temperature. Do not let this cool down first. Otherwise, it will resoldify. Solvents like methyl ethyl keytone and methylene chloride can be used for clean-up of residue only after disassembly.