Your right about needing a 'path' for the electrons to move. I just wasn't
going into details.
----Original Message Follows----
From: Mark <captainhoek@postmark.net>
To: "David A. Fox" <dafox1@hotmail.com>
CC: datsun-roadsters@autox.team.net
Subject: Re: electroytic metal erosion
Date: Fri, 25 Feb 2000 07:33:44 -0600
"David A. Fox" wrote:
>
> This concept certainly works for Marine aplications. Why not for cars?
> Actually I once had a mechanic suggest this to me when I was being
> reassigned overseas and my Roadster was going into storage for 3+ years.
> Didn't have the chance to get it done but what I'm saying is this isn't
the
> first time I've heard of this approach. The mechanic I mentioned
suggested
> putting a small block of magnesium in the trunk would work (outta sight).
>
No, just putting a chunk of magnesium in the trunk would not work. There
has to be an electrical connection between the sacrificial metal (magnesium
or zinc) and the metal to be protected. There ALSO must be a medium through
which the molecules of the sacrificial metal can move to the area of
corrosion. With marine application the "zincs" (as they are called) are
connected to the part to be protected and the medium for movement is the sea
water. In a radiator, it's the coolant, I suppose. This is an
electrical/chemical phenomenon, and you must have a complete circuit.
In expensive metal caskets (bronze, copper, or stainless steel) you may find
a piece of magnesium bonded to the bottom of the casket. The moist soil is
the medium through which the sacrificial metal moves. Dry soil? No
movement, but no corrosion, either. (This appplication may be more hype
than
substance, but it IS technically sound.)
--
Mark van der Hoek
Houston, for now
"They that can give up essential
liberty to obtain a little temporary
safety deserve neither liberty nor
safety."
-- Benjamin Franklin
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