[meteorite-list] Re: rust, cleaning, and silicone

From: magellon <magellon_at_meteoritecentral.com>
Date: Thu Apr 22 10:30:01 2004
Message-ID: <3F78110D.513CFEAD_at_earthlink.net>

Mark,
Actually you would want to do the reverse.
Pump the air OUT of the vessel.
This would cause the solution to permeate the meteorite immediately.
Best,
ken newton

mark ford wrote:
>
> Steve,
>
> Just a thought really, six months is a long time!, I was wondering if
> there would (in theory), be a way of speeding up the process? What about
> warming up the solution or putting the whole thing into a pressure
> vessel and pumping it up?
>
> could any of these idea's help the process to work quicker?
>
> Mark Ford
>
> -----Original Message-----
> From: Steve Schoner [mailto:steve_schoner_at_yahoo.com]
> Sent: 28 September 2003 16:52
> To: Stephen McMann; meteorite-list_at_meteoritecentral.com
> Subject: Re: [meteorite-list] Re: rust, cleaning, and silicone
>
> --- Stephen McMann <stephen_mcmann_at_hotmail.com> wrote:
>
> ---------------------------------
>
> Dear List,
>
> A quick question regarding rust. I have been mulling
> over a simple strategy for the long term care of my
> SAs (and other meteorites). Right now it seems that a
> good strategy is to give the SAs an alcohol and NaOH
> treatment to dispose of the Cl- from fingerprints
> etc., and otherwise keep them with VCIs and dessicant.
>
> A possible complication is that several of my SAs were
> once wiped with a silicone gun cloth (by me). However,
> for the alcohol and NaOH treatment to be most
> effective I assume that the silicone coating should
> go. What is a good method for removing such a
> coating? Will the alcohol and NaOH remove it? If
> anyone has some thoughts about this, I would be
> interested in them. Hopefully I am asking for
> information that is not just waiting in the archives.
>
> Sincerely,
>
> Stephen McMann
> ------
>
> NaOH with alcohol should remove it.
>
> Mix alcohol 70% with 40% or more of distilled water to
> avoid a layer of brine. If such a lay forms keep
> adding just enough water to eliminate that layer then
> the solution will be ready for soaking specimens.
>
> Currently, I am soaking several meteorites. A big 158
> lb Campo for Darryl Pitt, a small slice of Brenham, an
> end piece of Doronio, and a slice of Brahin for
> Matteo.
>
> All of these had advanced rusting problems. The large
> Campo has been soaking for 6 months in 25 quarts of
> solution, it should soon be ready for removal and
> drying in another month or so. If the flaking has
> stopped the specimen will be cured.
>
> The smaller pieces were treated with a coating, and
> the rust was quite bad. In fact two of the samples
> had fallen appart, and part of my process is to put
> them back together. Once the rusting is cured, after
> soaking these pieces for a month, reconstruction can
> be done with some patience. (Currently, at this
> point in my life I have lots of time).
>
> I will post the results.
>
> But again, yes, the NaOH will get through any coating
> that is on the specimen. In fact it will even soften
> a thick epoxy coating softening it like rubber which
> peels off.
>
> I have treated SA's before, and the fusion crust is
> not harmed other than the specific areas that are
> rusting with chlorides. These spots turn into dark
> brown oxides. But the oxide is very thin and
> superficial and with a tooth brush comes off to reveal
> the original surface underneath.
>
> Steve Schoner
> http://www.geocities.com/american_meteorite_survey
>
>
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Received on Mon 29 Sep 2003 07:01:33 AM PDT