You’ve successfully disassembled a component, but now you’re faced with the next challenge: a stubborn, flaky, or powdery residue of factory-applied threadlocker coating the threads of your screws and the interior of the bolt hole. You know you need to reapply your own adhesive for a reliable bond, but cleaning off the old stuff is proving difficult.
This scenario is extremely common in maintenance, repair, and overhaul (MRO) tasks. Failing to remove that old residue is one of the quickest ways to guarantee your new threadlocker, like the high-performance Incure Re-Lok™ series, will fail.
Why Old Threadlocker Must Be Removed
The entire principle of anaerobic threadlocking relies on the adhesive having direct contact with clean, active metal surfaces. When you apply new liquid threadlocker over old, cured residue, the following problems occur:
1. Weak Bond/No Cure
The old, cured threadlocker acts as an inert barrier. Your new liquid adhesive only bonds to the old plastic residue, not the metal. The cured material is often a porous or passive surface that does not provide the active metal ions needed to catalyze the anaerobic reaction, leading to a weak, partial, or failed cure.
2. Reduced Engagement
Dried threadlocker residue takes up space, effectively changing the thread geometry. This reduces the metal-to-metal engagement between the screw and the hole. When you re-insert the screw, you are essentially tightening it onto a brittle cushion of old plastic, which compromises the fastener’s fit and reduces the clamping force.
3. Contamination
Old, broken-down residue can sometimes mix with your new liquid threadlocker, compromising its chemistry and reducing its final strength.
The Thread-Cleaning Protocol: How to Prepare for Incure Re-Lok™
To ensure your Incure Re-Lok™ adhesive achieves its full, rated strength, thorough thread cleaning is non-negotiable. This is a multi-step process involving chemical action, mechanical action, and final degreasing.
Step 1: Chemical Attack (Soaking and Softening)
The cured threadlocker is essentially a thermoset plastic, making it difficult to dissolve. However, certain solvents can soften it for easier removal:
- Soak Fasteners: Place the removed screws into a small container of Acetone or a specialized adhesive remover/stripper (avoiding plastic containers for Acetone). Let them soak for 15-30 minutes to soften the residue.
- Wipe/Brush: After soaking, the softened residue will be much easier to remove.
Step 2: Mechanical Abrasion (The Necessary Scrape)
Chemicals alone are rarely enough. You must physically remove the old material from the thread roots.
| Component | Tool Recommendation | Technique |
| Male Threads(Screws/Bolts) | Wire Brush (Brass or Nylon), small die, or even a paper towel tightly held. | Wire Brush: Use a small, firm brush to aggressively scrub the residue from the threads. Towel Method: Tightly pinch the threads with a paper towel and “unscrew” the bolt from the towel to scrape out the residue. |
| Female Threads(Holes/Nuts) | Correctly Sized Tap or Thread Chaser | Tap: Use the correct size tap to clean (not re-cut) the threads, pushing out the debris. DO NOT use a tap if you are unfamiliar with thread pitch/size, as you risk damaging the threads. Alternatively, use a small, stiff-bristled brush (like a dental brush or pipe cleaner) with solvent. |
Step 3: Final Degreasing and Application Prep
Even after scraping, there is often solvent residue or fine debris remaining.
- Final Wipe: Clean both the male and female threads one last time with a residue-free solvent like Acetone or Isopropyl Alcohol (IPA) to ensure the metal is clean and ready.
- Incure Re-Lok™ Application: Immediately apply the appropriate Incure Re-Lok™ product (e.g., B43 Blue for standard duty) to the clean threads and assemble the component.
By dedicating the time to properly clean off factory and old threadlocker residue, you eliminate the “ghost bond” and guarantee that your new Incure Re-Lok™ adhesive can make direct, secure contact with the metal, giving you a reliable and lasting lock.