[meteorite-list] Cleaning a 13kg "Bessey Spec"! :-)

[Jerry]

Thanks for the information Graham, I especially appreciated the link to th e 
galvanic process.
Jerry Flaherty
----- Original Message ----- 
From: "ensoramanda" <ensoramanda at ntlworld.com>
To: "dean bessey" <themeteoriteshop at yahoo.com>; 
<Meteorite-list at meteoritecentral.com>; <gianpgg at hotmail.com>; 
<meteoritekid at gmail.com>
Sent: Tuesday, October 23, 2007 7:17 PM
Subject: [meteorite-list] Cleaning a 13kg "Bessey Spec"! :-)


> Hi Dean, all...
>
> Many thanks to all those who replied to me with tips on cleaning caliche 
> from meteorites and to you, Dean, for my 13kg "spec" which has become the 
> subject of several hours of careful cleaning.
>
> The monster before cleaning, below...showed great potential even though 
> quite weathered....but most was hidden under 2/3rds caliche. The exposed 
> area had some fusion crust but most had been scoured away and polished by 
> the sand and wind. Lovely thumbprints though.
>
> http://i117.photobucket.com/albums/o43/LaburnumStudio/13kgNWA/DSCN0009.jpg
> http://i117.photobucket.com/albums/o43/LaburnumStudio/13kgNWA/DSCN0008.jpg
> http://i117.photobucket.com/albums/o43/LaburnumStudio/13kgNWA/DSCN0007.jpg
> http://i117.photobucket.com/albums/o43/LaburnumStudio/13kgNWA/2080_1.jpg
>
> Looking closely when it arrived I could see tantalizing glimpses of what 
> appeared to be flow lines, lips and bubbly fusion crust in some thinner 
> areas of caliche. So I decided to brave it and set to work cleaning. 
> Because of the delicate features I wanted to preserve I did almost no 
> mechanical scraping or wire brushing but used brick cleaner (dilute HCl 
> acid) and small stiff paint brushes to gradually dissolve the caliche and 
> I was surprised how well it worked.
>
> I regularly washed the acid away with deionised water and bicarbonate of 
> soda to try and stop too much acid penetrating too deep. After a while 
> some of the well preserved fusion crust was revealed. Some areas almost 
> look fresh with bubbling and very thick accumulation. Remnants of flow 
> lines and roll over lips too....
>
> I did try some rust removers on some of the rust spots too....but they 
> seem very difficult to remove...nothing really worked ...infact I had to 
> reuse the brick cleaner to remove residues that were left.
>
> Once I was satisfied I could reveal no more without damaging the meteorite 
> I decided to make sure I had removed all the acid and chlorides left which 
> might cause future problems and used the galvanic method described here...
>
> http://www.alaska.net/~meteor/Galvanic.pdf
>
> I used the less agressive washing soda method in a large bucket with 
> plenty of  perforated aluminium foil wrapped around the meteorite to allow 
> circulation and electrolosys to work overnight.  I did this twice until 
> the bubbling reaction stopped.
>
> Finally I rinsed well again with plenty of dionised water and left the 
> meteorite to dry thoroughly in the oven on a low heat for a couple of 
> nights. It remains to see how stable this meteorite is over time...we will 
> see.
>
> I know many collectors like to leave pieces as found without tampering 
> with their looks....but in this case I felt that the exercise was worth 
> it.  There was so much hidden away under all that caliche.
>
> Take a look here and see what you think of the cleaned up result!
>
> http://i117.photobucket.com/albums/o43/LaburnumStudio/13kgNWA/IMG_4198b.jpg
> http://i117.photobucket.com/albums/o43/LaburnumStudio/13kgNWA/IMG_4170b.jpg
> http://i117.photobucket.com/albums/o43/LaburnumStudio/13kgNWA/IMG_4177b.jpg
> http://i117.photobucket.com/albums/o43/LaburnumStudio/13kgNWA/IMG_4189b.jpg
> http://i117.photobucket.com/albums/o43/LaburnumStudio/13kgNWA/IMG_4195b.jpg
> http://i117.photobucket.com/albums/o43/LaburnumStudio/13kgNWA/IMG_4194a.jpg
> http://i117.photobucket.com/albums/o43/LaburnumStudio/13kgNWA/IMG_4199b.jpg
>
>
> Please be aware that these methods are probably risky and who knows what 
> the long term effects may be...so I would advise caution to anyone trying 
> this with acids etc.(The troilite and probably other surface minerals in 
> the meteorite will obviously be changed to some degree, as evidenced by 
> some sulphurous smells during cleaning) Different meteorites may react in 
> different ways and some deposits may not dissolve away.  So please don't 
> try this on something you may regret ruining. I would not like to be held 
> responsible for that. I was more interested in the aesthetic external 
> qualities in this case...so was willing to take the risk....although I may 
> polish a window in an uncrusted area next...just out of curiosity! :-)
>
> Regards
>
> Graham Ensor.
>
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