[meteorite-list] How I (mis)treated my Brahin

From: Göran Axelsson <axelsson_at_meteoritecentral.com>
Date: Fri Jun 17 07:21:51 2005
Message-ID: <42B2B34E.6080806_at_acc.umu.se>

I bought a Brahin slice about eight months ago. When I got it it was already
rusty even though it was sealed. The rust were everywhere under the lacquer
and had even seeped through and stained the paper it was wrapped in.
It was also broken in three pieces in the freight.

The seller told me it wasn't rusty when he sent it. It was hard to belive
but I let it rest and thought it was what you had to pay to learn.

What to do? Well, I stripped the lacquer on a test piece by sanding it. Then
I polished it again by hand (in isopropylic alcohol) and dried it in the
oven
at 70 degrees celsius for a couple of hours.
It's now been without any protection on a shelf for over six months, handled
by hand (showin it to friends and at the club) and doesn't have a trace of
rust yet. It's just a 20g piece so I'm using it to see how sensitive it is.

The bigger piece was stripped of the lacquer by CRC sealant stripper!
It worked a lot faster than sanding it down. Then I gave it a quick polish
and it too haven't had any problem.

I use isopropylic alcohol before I cut meteorites as I have access to a
rock saw with water based coolant. It goes into the pores and stops
the water to go deep into it, it's so much easier to dry it afterwards.

So far it's been working for me, but your mileage may vary.

To form rust you need two things, oxygen and a media for the wet
chemistry process to work in. If you could take away one part of
the equation you could stop the rust forming.
So either an inert atmosphere (nitrogen, carbon dioxide, neon... ),
vacuum or absence of water will protect a specimen.

The problem is to remove the water if there is any iron chloride
salts present. That will work as a dessicator, drawing the humidity
from the air and creating a perfect environment for rusting.
The chloride irons also add to the process as a catalyst.
My next step is to try to treat a piece of Brahin electrolytically
to draw out the chloride. I'll come back later to report how it went.

I do also belive in the preservation of Brahin is possible with
the right treatment. I'm not giving up on this yet.

Now I'm off to a mineral fair i Kopparberg. No, no Ensisheim for
me, it's too far away.

/G?ran

Jim Strope wrote:

> I agree with Matteo. You get what you pay for. Esquel, Imilac,
> Albin, Glorietta, and a few others are investment quality pallasites.
>
> Brahin, Brenham and Admire have always had a bad reputation in general
> although there are some speicmens that have lasted for years with no
> traces of rust. I do believe that Brahin CAN survive with the proper
> cutting and preparation, however.
>
> Jim Strope
> 421 Fourth Street
> Glen Dale, WV 26038
>
> http://www.catchafallingstar.com
>
>
Received on Fri 17 Jun 2005 07:26:06 AM PDT