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.