Re: [ATM] Polishing staining

["Scott Milligan" <starzkey@charter.net>]

Thoughts:

1. Hard water, or dissolved iron, manganese, etc. maybe accelerating
chemical attack during polishing.  Plate glass has a much higher content of
relatively active (chemically speaking) ion-forming constituents, such as
sodium oxide.  Using distilled water for polishing could help here, but I
have occasionally come across these kinds of problems even taking this
precaution.
2.  Clean the work thoroughly immediately after each spell, don't let the
ceo + water solution dry on the surface, or leave a film.
2. After the fact, try dissolving some fine precipitated calcium carbonate
in water, flood the mirror with water, and using a fresh, wet cotton ball,
gently swirl the calcium carbonate solution across the surface, working the
entire surface evenly.  Calcium carbonate is much softer the CEO, and while
I've never observed this process to change a surface figure or cause
scratches, it has rescued more than a few cases of stubborn staining in my
career.  You can buy the stuff at any decent chemical supply house without
needing to show 1207 forms of picture ID.

Hope this helps,

Scott Milligan, Owner
Astroverted Optics
10 Woodview Drive
Hubbardston, MA 01452
978 820-1011 (Voice)
978 978-4834 (Fax)
www.astroverted.com

-----Original Message-----
From: atm-bounces@atmlist.net [mailto:atm-bounces@atmlist.net] On Behalf Of
Douglas Arion
Sent: Thursday, January 17, 2008 10:37 AM
To: atm@atmlist.net
Subject: [ATM] Polishing staining

Hi everyone,

I'm doing my bi-annual ATM class here...and having a
problem I've seen once before that seems to be
inexplicable: Polishing plate glass 6" blanks on Gugolz 64
using CeO from Salem, several of the students get a thin
filmy coating on their mirros which seems to be removable
with acetone and hard, and I mean hard, rubbing (we're
using surgical cotton), which does optically affect the
glass (which is then polished out with the next session).
Any ideas what's causing this? Was to eliminate it? Not
everyone gets it (I have fifteen mirror makers at the
moment), and no one who gets it sees it all the time, just
intermittently.

Thanks,
Doug

 
 

_________________________________
Dr. Douglas N. Arion
Hedberg Distinguished Professor of Entrepreneurial Studies
Professor of Physics
Head Coach, Ice Hockey
Carthage College
2001 Alford Park Drive
Kenosha, WI 53140
262-551-5864
262-551-6208 (Fax)
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