I've seen this a few times. I never knew exactly what it was but it
usually comes off but there is staining left over. Here are a couple of
explanations from Google.
*White rust* is a *white* powdery deposit formed from a natural *corrosion*
process that can occur on any new zinc coated steel product. It is damaging
to the appearance of the steel, not to mention to the anti-*corrosion*
layer of zinc that protects the body of the steel.
Galvanized *metals* also *rust*, but they do so at a slow rate unless the
galvanized coating has been damaged. Brass, silver, and bronze tarnish as
they interact with the atmosphere. Aluminum oxidizes into a *white powder*,
although the *powder* binds chemically to the *metal* beneath, blocking
further *corrosion*.
On Fri, Dec 8, 2017 at 6:09 PM, Adrian Stoness via cctalk <
cctalk at classiccmp.org> wrote:
water get sprayed on it?
On Fri, Dec 8, 2017 at 5:06 PM, dwight via cctalk <cctalk at classiccmp.org>
wrote:
Could be the zinc plating?
Dwight
________________________________
From: cctalk <cctalk-bounces at classiccmp.org> on behalf of Sam O'nella
via
cctalk <cctalk at classiccmp.org>
Sent: Friday, December 8, 2017 2:46:40 PM
To: General Discussion: On-Topic and Off-Topic Posts
Subject: Types of corrosion on computers
I've seen rust and dust, but there's an old vaxstation II at Goodwill
Computers in Austin right now (very cheap, anyone welcome to buy it and
get
it off my mind) but as most things, I checked out
the back and see some
circles of white corrosion on the back where the cards? are contacting
the
case.
I don't really have room or time but I don't own anything that uses QBUS
or
is almost related to some of the neat iron some
of you all collect (I've
mostly collected way too many home computer history items).
Anyway, what is that type of white corrosion on metal? Would one
probably
assume this means any bus would be corroded and
this wouldn't be a
computer
for the faint of heart hobbyist? I've only
seen that maybe from batteries
but it's in an unusual place and pattern (I think).