[Mgs] Positive ground = more rust?

[Richard Gosling]

"...but if you reverse the polarity something else has to corrode, so what
that was going to be I can't recall..."

Well, that would make any live wire more vulnerable to corrosion, instead of
anything that was earth.  But since the live wires are pretty well protected
by their insulation, and are mostly copper or aluminium anyway (neither of
which corrode in a way that leads to failure), that isn't really a problem.

The dodgy bit of this whole theory is that, for electrolytic corrosion to
occur, current needs to flow through something that surrounds the metal.
Under water the current can flow through the water, particularly sea water.
Buried underground there is enough moisture around for the current to flow
through that.  But our cars are surrounded by air - except when it rains!
This is why the magic electronic devices that are sold to prevent rust are a
waste of time - they work well in demonstrations, because plenty of water is
involved, but unless there is a continuous path of water between the device
and every bit of metal on your car it's not going to protect your car.
Richard & Sammy ('73 Black Tulip BGT)