Re: "Loc-tite" for electrically conductive connections

Any of these useful or adaptable?

In a threaded electrical connection, the current is carried entirely in the metal of screw and nut, and mating faces of terminals. These surfaces are very rough at the scale of interest, and it's the asperities that touch make the electrical (and mechanical) connection. The space between asperities can be filled with anything.

For battery terminals, being lead on lead, I would fill the gap with silicon grease and then install battery cable clamp on the post. The mating force displaced the grease, which filled the gaps and greatly slowed the entrance of sulfuric acid.

For a terminal, ordinary loctite will do the same.

Joe Gwinn

I think that could result in loctite fracture due to differential thermal expansion or shock and vibration, allowing gas ingress and moving some of those small asperites over non-conductive loctite. Better would be putting a listed conductor termination compound on the terminal mating surfaces - for copper or plated copper terminals Thomas&Betts Kopr-Shield is good, Burndy makes an equivalent also conforming to MIL-PRF-907E, and there are a multitude of compounds for aluminum. Put the loctite only on the threads of the screw, being sure that no termination compound gets in the nut threads, and of course always use a torque screwdriver to tighten to the correct torque. For better reliability in harsh conditions use a belleville washer between screw or bolt and terminal, this combo is commonly used in power distribution terminations but is trickier to design so that the spring exerts the correct force and operates near its constant force deflection.

Glen

I'd expect the regular Loctite to work fine. Try it.

The real nuisance is scruncing screws down into countersunk anodized holes. Undercut flathead screws seem to cut through the anodize and make a good connection.

Star lockwashers dig into metal pretty good too.

There is electrically conductive Loctite. It costs more than fine caviar.