Re: [ATM] 5.3 kg Cu3Sn Protection

["Colton" <clnoble@email.arizona.edu>]

I don't know if this would be worth pursuing, but I think that it would be
possible to stop the tarnishing of a speculum mirror by attaching a
sacrificial anode to it.  A quick look in a chemistry book showed that
readily available materials such as zinc, magnesium, and sodium all had
lower redox potentials than the copper and tin.  This means that the
attached "sacrificial" anode would rust before the speculum, essentially
sparing the mirror.  Systems such as this are in existence, and are commonly
referred to as cathodic protection.  Large ships often have large pieces of
zinc bolted to their hulls to prevent the destruction of the hull, and many
natural gas lines have bags of magnesium attached to them so that the iron
pipes do not rust.  I would bet that it would be easy to wire such a metal
to the speculum to prevent it from rusting.  If nothing else, it might
drastically slow down the process enough so that they would not have to be
refigured so often.

Colton
----- Original Message ----- 
From: "Lawrence D. Lopez" <lopez@mv.mv.com>
To: <atm@atmlist.net>
Sent: Thursday, April 15, 2004 11:37 AM
Subject: Re: [ATM] 5.3 kg Cu3Sn


> Can you aluminize or multi coat a speculum mirror ?
>
> I'm not sure where this question is going but I suddenly realized
> it might not be impossible to stabilize the surface on a speculum
> mirror against corrosion or whatever requires you to repollish it
> periodically.
>

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