Re: [ATM] Mirror Polishing

["Thomas Janstrom" <tomjan@ozemail.com.au>]

You really should alternate ToT (Tool on Top) with MoT (Mirror on Top),
that way you get a more even polish, ie the whole surface will polish at
a more uniform rate, that way you are less likely to get a fully
polished edge and partial center such as you describe.

To correct your surface you will have to work MoT for a while, being
careful to press regularly, and trying not to heat the edge of the
mirror too much, can you ware gloves? White cotton one's will help with
this, although if your work environment is a bit warm this may not be an
option. If this is the case don't work for long spells, do more short
ones (5 to 10 mins) with cold pressing between sessions (about the same
time frame), and aim for a 1/3 mirror diameter overhang, center over
center (CoC) stoke.

This should polish out the center of your mirror and bring the edge up,
it sounds like you have a turned down edge, although you haven't given
us too much info to work with.

BTW what are specs on the mirror you doing?

Clear Skies, Thomas.
www.tjanstrom.com
www.norsewines.com.au 

-----Original Message-----
From: atm-bounces@atmlist.net [mailto:atm-bounces@atmlist.net] On Behalf
Of Troy Madden
Sent: Wednesday, 26 October 2005 8:12 PM
To: ATM@atmlist.net
Subject: [ATM] Mirror Polishing

I am in the process of making my first mirror. So far it has been alot
of fun and quite the learning experiance! I have begun polishing and am
wondering if it is OK to begin polishing right after a warm press or
should one wait until the mirror and tool reach room temperature? I
warmed the mirror and pitch lap on a light table I made with a 100 watt
bulb  inside a 5 gal. bucket with plexi on top (I  used this to check
pits) and it gets fairly warm. Also the mirror seems to be polishing
from the outer edge in, almost no pits towards the outside, but still
quite a few towards the center. Is this normal? I threw together a
foucault/rochi tester today and the ronchi bands show the outer zone
lower than the center.
I have been polishing with lap on top, going to try mirror on top.

Thanks,
Troy
_______________________________________________
ATM mailing list http://www.atmlist.net/

-- 
No virus found in this incoming message.
Checked by AVG Free Edition.
Version: 7.1.361 / Virus Database: 267.12.4/146 - Release Date:
21/10/2005
 

-- 
No virus found in this outgoing message.
Checked by AVG Free Edition.
Version: 7.1.361 / Virus Database: 267.12.4/146 - Release Date:
21/10/2005
 

_______________________________________________
ATM mailing list http://www.atmlist.net/