----- Original Message -----
Sent: Thursday, December 27, 2001 7:48
AM
Subject: RE: ATM alternative grinding
materials
Dennis:
A few years ago we hosted a
student from Tashkent for 1-year of secondary school study here in the
US. A few days ago he telephoned us that he is again in the US,
visiting. Presuming that I can contact him again while he is here, that I can
get some polishing materials to him, and that he would not have difficulty
getting it through airport security and customs, he may be able to hand-carry
some cerium oxide to you.
Richard Klappal
Hi All,
This is the first time I'm posting message to the list. And first of
all I would like to greet all of you. It's really so great when people share
their hardly won experience following the real ATM spirit.
In 1991 I was to pause my ATM practice due to specific economic
and social conditions (poverty and total disorder) in my country and
collapse of Soviet Union. I'm russian and I live in Tashkent/
Uzbekistan but still I call this country Russia mostly because of my
mind's inertia. Nowadays things are going beter, so good that I decided to
go on with telescope making. The first surprise is that there are
no abrasive vendors left on the local market. Briefly speaking I
can not find even a simplest emery.
I have experimented with the ordinary sand and found out that this kind
of material is absolutely insufficiend for glass grinding. It breaks down
after a couple of strokes and seems to do very poor work on a glass. My
next idea is to use silica. As I remember from the university
mineralogy course - silica is 1.4 times softer than emery, and 2
times softer than aluminium oxide. The difference is not too big.
I found out that the grit used in metalurgy for sand blasting and moulding
is almost pure silica. Now I'm almost sure that it will work
but before I try I'd be happy if anyone will confirm or deny this
idea.
The same story with polishing materials. I can not find either
cerium oxide or the red powder (sorry I dont know what is it in
English). The idea is to use green chromium dioxide(Cr2O3).
This stuff is used for polishing metals. I don't have a fine grinded glass
to try it but I polished a 100 years old copper kettle - the result is very
impressive. All comments are wellcomed.
By the way sorry if I'm rising theme which is chewed and swallowed many
times ago, but I haven't found anything on the subject in russian ATM
literature.
Best wishes, Merry Christmas to all.
Dennis Nikitin,
Tashkent/Uzbekistan.