[meteorite-list] surface treatments/ oils...

From: Michael L Blood <mlblood_at_meteoritecentral.com>
Date: Wed, 28 Mar 2007 09:28:47 -0700
Message-ID: <C22FE5CF.34834%mlblood_at_cox.net>

on 3/27/07 9:47 AM, drtanuki at drtanuki at yahoo.com wrote:
> The abrasion tool that I have seen can be used to
> remove soil or rust from the Gaos and other
> meteorites. It is basically a sandblaster that has a
> stylus like a pen. I don`t know what a "bead blaster"
> is.
Hi Dirk and all,
        In a "sand blasting" unit, one can use any number
of materials for cleaning. You can see the same thing
in "tumblers" in the rock trade.
        One can use sand (Si02) which is a hardness of 7
on the Mo's scale down through cork, which is under
a hardness of 2. Some even use lead beads.
        For meteorites, a decent choice is tiny glass beads
with a hardness softer than the fusion crust (man made
glass is approximately a 5). However, even with glass
beads, care must be taken to keep from "blasting off"
parts of the fusion crust, since the force of the unit can
do that - much like a tornado can rip off the roofs of
buildings. In addition, even with softer material, the
"peeks" of fusion crust can be rounded off - highly
undesirable in my opinion. So, how far one holds the
tip of the "sand blaster" from the stone, the amount of
pressure used in the unit, How long the material is exposed
to the treatment, etc, all play into being able to remove
rust and/or dirt without harming the fusion crust.
        A skilled hand and fine eye can, with experience,
remove rust from most meteorites without damaging
the fusion crust - depending on many factors.
        So, to say blasting does or does not alter the fusion
crust is na?ve. Some times it does not - many times it
does. Going very slowly and checking closely to exactly
what is being removed and or altered is a requirement
of the person using the blaster. Use of a microscope
greatly aids in this, but increases the time by many
factors - and I believe most dealers do NOT
have a clear understanding of the intricacies of the
process and/or take sufficient care in their work to
insure fusion crust is left unaltered.
        Best wishes, Michael

--
"What fits your busy schedule better, exercising one hour a day
or being dead 24 hours a day?"
----Anon
--
Fighting for peace is like screwing for virginity.
---Graffito: The Bayou, Baton Rouge , LO
--
  

Received on Wed 28 Mar 2007 12:28:47 PM PDT