Should the nuts and bolts be cleaned before using threadlocker MM115?

Permabond MM115 tolerates some oil on the nuts and bolts.  In most cases, it is perfectly ok to use Permabond MM115 on ‘as received’ nuts and bolts. We recommend testing, particularly if nuts and bolts appear heavily contaminated.

A couple of points to consider:

• Metal ions are needed for the MM115 threadlocker to cure. Too much contamination on the components can reduce the amount of metal ions in contact with the threadlocker. Thus causing the adhesive to cure more slowly and hindering the strength development.
• Threadlockers work by filling the microscopic voids in the metal surface, providing better surface to surface contact, stress distribution, and protection against moisture ingress. If these gaps are filled with oil and grease, then the adhesive can’t get in. This affects final performance.

If you always clean and degrease nuts and bolts before using Permabond MM115, you can be confident in achieving consistent bonding and sealing performance every time. If you don’t want to do surface preparation, consider a more oil–tolerant threadlocker. Permabond HM129 may be suitable but it depends on your requirements.

If you decide to clean components before bonding, a suitable degreaser would be acetone or isopropanol. Alternatively, use Permabond ASC10 activator as a cleaning agent on nuts and bolts and speed up adhesive cure.