Copper Compound

Copper grease, also sold as copper compound or anti-seize, is an assembly paste rather than a bearing lubricant. It carries fine copper particles in a grease carrier so that a protective solid film remains long after the carrier has burned or washed away.

It is used on exhaust manifold studs, brake caliper slides and pad backing plates, spark plug threads on some engines, flange faces and any fastener expected to come apart again after heat and corrosion have had time to work. The copper film stops threads seizing and galling, so the bolt undoes cleanly instead of shearing.

Two cautions worth knowing: keep it off friction surfaces, ABS sensors and rubber components, and avoid it on aluminium assemblies where copper can promote galvanic corrosion. A thin smear is enough, more does not help.