On Tue, 18 Aug 2015 12:01:51 -0700 (PDT), whit3rd
wrote:

On Tuesday, August 18, 2015 at 8:20:56 AM UTC-7, Jeff Liebermann wrote:
On Mon, 17 Aug 2015 15:56:53 -0700 (PDT), wrote:

Battery and ground contact areas eg terminals, clamps, frame connection areas are coated with a thin film of [silicone grease]

suggested that he grease his sheet metal pieces before spot welding
... the grease exploded in the spot welder
and produced a rather wide black horizontal scorch line across his
clean white shirt.

Yes, grease is good, but not in the current flow.

There's formulations of grease that don't do that, of course; silicone takes high
temperature, and some greases are intended for electrical conduction in thin
films (they 'break down' at millivolts, and don't even get hot).
http://store.caig.com/s.nl/sc.2/category.185/.f
I've used this grease on rotating connections, at 40A it's just like
a solid wire connection.

Looks like aluminum dust, copper dust, graphite, and/or quartz(???).
No clue if it's graphite spheres or flakes. Ignoring quartz, the
others are not particularly great conductors because of the lack of
sufficient contact area between particles. It's much like the
conductive PCB paint used to "print" conductive traces. Even using
silver, it's not very conductive. Graphite flakes are tolerable
because the flakes overlap, but still produces high resistance
connections.

One your rotating joint connection, did you use brushes or a
commutator to make the connection? If so, the path of least
resistance is through these connections, not through the grease.
Grease will certainly help, but it works by burying any small arcing
under a layer of grease, which blocks oxygen to the arc, and therefore
reduces pitting and burning.

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558