[meteorite-list] question on cleaning irons

From: Galactic Stone & Ironworks <meteoritemike_at_meteoritecentral.com>
Date: Sun, 27 Sep 2009 16:55:42 -0400
Message-ID: <e51421550909271355y5a303774pd15a38a36085dab_at_mail.gmail.com>

Hi Jason and List,

I concur with Jason here about flowlines on a Nantan.
Oxidation/weathering is a replacement process - any oxide "rind" that
is on the specimen is representative of lost mass and surface area.
Since flowlines reside in the outer millimeter or so of the crust, any
such flowlines on a Nantan (or similar iron) would have been
eradicated by mother nature long ago. No amount of mechanical or
chemical cleaning will restore that lost mass.

But I do agree that a vigorous mechanical cleaning will yield pleasing
results with almost any ugly corroded iron. :)

Best regards and clear skies,

MikeG


On 9/27/09, Jason Utas <meteoritekid at gmail.com> wrote:
> Hello Guido, All,
> Regardless of how well you cleaned your Nantan, whatever you found
> under the surface was not flow lines. The material you removed from
> the surface of your iron was a good portion of the exterior of the
> meteorite itself; you were likely centimeters below the original
> surface of the iron. Some Campos still have fusion crust, though it
> is very uncommon. At least many of them haven't been corroded badly
> enough to drastically alter their morphology. Nantans have been so
> weathered that there's not much of a trace of their original surface
> shape remaining, to say nothing of fusion crust.
> Regards,
> Jason
>
> On Sun, Sep 27, 2009 at 8:59 AM, <countdeiro at earthlink.net> wrote:
>> Mike in Co & List,
>> Good question Mike. I have a big ugly Nantan of about 2000 gr. that was
>> covered in concretions and rust. I ended up high pressure sandblasting it
>> and ended up with a very even grey patination. I then struck it with a
>> hammer and it cleaved along natural lines. When I blasted these interior
>> surfaces I got the same dark grey color. Interestingly, the sanding did
>> not remove metal, and flow lines were revealed. Deciding that this
>> abrasive removal was acceptable, I took a 600 gr. rusted Campo and tried
>> stainles steel wire brushing with a hand held Dremel tool. This also
>> resulted in an overall dark grey patination with all of the aerodynamic
>> and melt features still present.
>>
>> I would ask the List for a discusion on, not only your interst in
>> electrolysis for removing non-meteoric material, but the wire brush
>> technique also,
>>
>> With regards to all,
>>
>> Guido
>>
>> -----Original Message-----
>>>From: Michael Murray <mmurray at montrose.net>
>>>Sent: Sep 27, 2009 9:49 AM
>>>To: Meteorite-list at meteoritecentral.com
>>>Subject: [meteorite-list] question on cleaning irons
>>>
>>>I'd like to try cleaning a small suspect iron so that I can see what
>>>it looks like without all the rust and other buildup. Anyone have
>>>experience with using an electrolysis bath on an iron to clean it up?
>>>If so, another question...Will it remove the black oxide?
>>>Mike in CO
>>>______________________________________________
>>>http://www.meteoritecentral.com
>>>Meteorite-list mailing list
>>>Meteorite-list at meteoritecentral.com
>>>http://six.pairlist.net/mailman/listinfo/meteorite-list
>>
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Received on Sun 27 Sep 2009 04:55:42 PM PDT