Re: [a/s] Rivets Rivets Rivets

[Susi and John Burchard <saluqi@xxxxxxxxxxxxx>]

As a marine biologist I have had to devote quite a bit of my time to boats and
their logistics in the marine environment.  Galvanic corrosion is, as you say, a
nightmare.

There are, however, many different kinds of stainless steel, with different
positions in the "electromotive series" -- and some of them when properly
"passivated" are almost compatible with certain aluminum alloys.  It's been
quite a while now and I no longer remember all the details (marine engineers
have handbooks for this sort of thing).  One of the problems there is that
anything which has undergone any kind of surface treatment may change its
electrical characteristics when something disrupts that surface ... for
instance, when you scrape it by going aground.

In the marine environment, the way to get around most of this is an "impressed
current" cathodic protection system, which has a sensor (platinum electrode) to
detect the electromotive potential actually generated by the structure (boat) in
question, and a solid-state controller to apply just the right counter-voltage. 
But that would not work on a trailer where the different parts are not
"immersed" in the same liquid.

John