[meteorite-list] Hard to Polish Meteorites - Any Ideas? (diamond grit sandpaper?)

From: Count Deiro <countdeiro_at_meteoritecentral.com>
Date: Fri, 28 Oct 2011 15:26:47 -0700 (GMT-07:00)
Message-ID: <19628540.1319840807935.JavaMail.root_at_wamui-hunyo.atl.sa.earthlink.net>

Hi Mike and List,

Purchase the diamond polishing blocks online at:

http://www.contractorsdirect.com/Tile-Tools/Polishing-Pads-Buffing-Compounds/Diamond-Hand-Pad-Polishing

These are easier to use than the individual grit blocks and they are the same price. $100.00 I use a shallow plastic tray with a 1/2 inch, or so of distilled water and place the block in the bottom and move the meteorite by hand. Larger examples I hold on the bottom of the pan and move the block instead. Just enough water in the bottom to sluice off the block every few strokes.

I find the argument that distilled water is bad for anything other than a pristine specimen undergoing scientific study unconvincing. I have had no incidents of accelerated deterioration, or rusting, with a specimen that has dried and stored properly. Just think how much water the stone has been subjected to in the hundreds to thousands of years prior to being found. (new falls excepted). Ambient high humidity locations subject your stones to water no matter what.
I'm fortunate to live in the desert.

Best regards,

Count Deiro
IMCA 3536

-----Original Message-----
>From: Michael Gilmer <meteoritemike at gmail.com>
>Sent: Oct 28, 2011 2:55 PM
>To: Count Deiro <countdeiro at earthlink.net>
>Cc: Ed Deckert <edeckert at triad.rr.com>, meteorite-list at meteoritecentral.com
>Subject: Re: [meteorite-list] Hard to Polish Meteorites - Any Ideas? (diamond grit sandpaper?)
>
>Hi Count and List,
>
>You are fortunate to work with Adam firsthand and watch him work his
>magic. It's no secret in the collector world that the Hupes do some
>top-notch preparation work for all of their specimens. When I
>purchase a meteorite from Adam or Greg, I know I am getting some of
>the best preparation available, even if the specimen is a small micro.
> I wouldn't expect them to divulge their trade-secrets for
>preparation, but I was hoping for a couple of pointers on how to
>polish these hard to polish types.
>
>The responses I have received in public and private have been valuable
>and I am very thankful for the advice.
>
>It seems part of my "problem" is dry sanding and part is the fact that
>I don't have a lap-polisher. I guess I could do some wet-sanding,
>using distilled water, but I don't like introducing moisture into a
>specimen unless it is absolutely necessary. That is why the specimens
>I prepare are stable and free of oxidation. The only water my
>specimens see is during cutting (which is unavoidable) and then they
>go straight into a hot waiting oven for 6-10 hours to purge all
>remaining water. I use distilled water during cutting. Once the
>pieces are dry, I don't like getting them wet again. But, I will try
>some wet-sanding tonight and see how it goes.
>
>Does anyone know if/where I can purchase some diamond grit sandpaper
>for hand-sanding? I have been using the typical carbide sandpaper
>from the local hardware store - 100, 200, 320, 400, 600. I purchase
>higher grits online because they are hard to find locally without
>paying an arm and leg - 800, 1000, 1200, 1500. But I don't recall
>seeing any sandpaper with diamond-based grit. I'd like to locate some
>if I can.
>
>Right now I am polishing a gorgeous IMB meteorite for another dealer.
>This meteorite takes a great polish, unlike the CR2 I am also
>preparing. I'll be busy polishing most of the night and my right-arm
>will be tired to the point of fatigue. I should have an incredible
>Hulk right arm by now. On the bright side of hand-polishing - I am
>learning to use my left hand/arm to good effect, once my right side
>tires out. LOL
>
>Best regards,
>
>MikeG
>--
>---------------------------------------------------------------------------------
>Galactic Stone & Ironworks - Meteorites & Amber (Michael Gilmer)
>
>Website - http://www.galactic-stone.com
>Facebook - http://tinyurl.com/42h79my
>News Feed - http://www.galactic-stone.com/rss/126516
>Twitter - http://twitter.com/galacticstone
>---------------------------------------------------------------------------------
>
>
>
>On 10/28/11, Count Deiro <countdeiro at earthlink.net> wrote:
>> Hi Peter, Ed, Mike and List,
>>
>> I have spent a few days cutting and polishing dozens of various types with
>> Adam Hupe'. With his guidance I set up my own shop with 6" and 8" saws and
>> table and hand mounted polishing equipment. Basically, Adam uses quality
>> diamond blades and arbor free polishing discs. Inspection cuts and slices
>> are made with as fine a blade as will do the material in order to keep the
>> kerf as thin as possible and reduce loss.. and at the same time eliminate
>> the deep saw marks left by cheaper, thicker, blades.
>>
>> Polishing is accomplished with diamond impregnated discs both powered and in
>> hand held blocks. He is a virtuoso with being able to turn our nice even,
>> polished slices by hand. But, I never saw him dry cut or polish anything. He
>> uses distilled water. This could be the secret, because when I used the same
>> equipment dry, I couldn't get the same results until I added water for
>> cooling and cleaning. The water also adds a fine abrasive sedimentary
>> element to the polishing mix that I think is overlooked in it's ability to
>> take up minute imperfections.
>>
>> Because of the fine (max.018) cut of his blades, I rarely found that I had
>> to use coarser grained material to start polishing. Oh! Yes! It's really
>> important to dress and clear the saw blade between cuts by running it
>> through a piece of hand held common red brick. I could get by starting with
>> 600 grit on small samples of friable material and move right into 1000 and
>> then go on up. Bigger, harder, meteorites, or where I may have gotten ham
>> handed with the saw, required 300 to start. Remember these are diamond
>> impregnated polishing discs and hand held blocks like the type used by
>> masons to finish counter top granite and marble. They can be bought in sets
>> on eBay. I learned from Adam how to hand hold specimens safely while cutting
>> and polishing. We both agree that there is something to feeling the pressure
>> through your fingers on the stone.
>>
>> All of this seems, I'm sure, very ordinary and it isn't rocket science, but
>> the key info here is to use the best diamond abrasives and the smallest
>> diameter blades... and work by hand...and use water to carry off the removed
>> material from the surface. Dry them out in the oven and fine finish wit
>> ultra fine jeweler's non-resin cloths.
>>
>> P.S. Watch out for Urelites...they eat polishing discs.
>>
>> Have fun,
>>
>> Count Deiro
>> IMCA 3536
>>
>>
>>
>> -----Original Message-----
>>>From: Michael Gilmer
>>>Sent: Oct 28, 2011 9:34 A>Cc: meteorite-list at meteoritecentral.com
>>>Subject: Re: [meteorite-list] Hard to Polish Meteorites - Any Ideas?
>>>
>>>Hi Peter, Ed, and List,
>>>
>>>I know that the Hupes have a powered lap-polisher that most likely
>>>uses a diamond grit. I need to break down and buy a lap-polisher
>>>(flat lap). But I typically don't sand enough material to warrant the
>>>expense of a flat lap. Also, I enjoy hand-sanding and find it to be a
>>>zen-like relaxation exercise when combined with the right music. :)
>>>
>>>But, every now and then I run across a meteorite that is stubborn and
>>>won't take a polish. This is to be expected from friable types likes
>>>LL6, most carbonaceous types, etc. But I know CR2 types are quite
>>>hard and robust (also most CV3), so I expected this CR2 would be easy
>>>to polish. Thus far, it has resisted my efforts to beautify it. It's
>>>taking the polish, but the detail is becoming muddy and lost. I
>>>thought it might be because I dry sand and powder from the sanding was
>>>getting embedded in the matrix. So I tried giving the slice a quick
>>>bath in alcohol, which removed most of the powder, but didn't improve
>>>the appearance.
>>>
>>>I have some 1200 and 1500 grit sandpaper, and I tried going straight
>>>to those (skipping 400-1000), but the result is the same - muddy
>>>matrix and subdued chondrules.
>>>
>>>Best regards,
>>>
>>>MikeG
>>>--
>>>---------------------------------------------------------------------------------
>>>Galactic Stone & Ironworks - Meteorites & Amber (Michael Gilmer)
>>>
>>>Website - http://www.galactic-stone.com
>>>Facebook - http://tinyurl.com/42h79my
>>>News Feed - http://www.galactic-stone.com/rss/126516
>>>Twitter - http://twitter.com/galacticstone
>>>---------------------------------------------------------------------------------
>>>
>>>
>>>
>>>On 10/28/11, Ed Deckert wrote:
>>>> Hi Mike,
>>>>
>>>> Perhaps the Hup?'s "trade secret" is using diamond polishing media at a
>>>> much
>>>> higher/finer grit than you are using? It may be worth a try.
>>>>
>>>> Adam & Greg, can you share your secret?
>>>>
>>>> Ed
>>>>
>>>> ----- Original Message -----
>>>> From: "Michael Gilmer"
>>>> To:
>>>> Sent: Friday, October 28, 2011 9:06 AM
>>>> Subject: [meteorite-list] Hard to Polish Meteorites - Any Ideas?
>>>>
>>>>
>>>>> Hi List,
>>>>>
>>>>> Some meteorites are hard to polish or just won't take a proper polish.
>>>>> Allende is one example that comes to mind readily.
>>>>>
>>>>> I've got an endcut of NWA 801 CR2 that came from the Hupe Collection.
>>>>> It has a wicked glossy polish on it that accentuates the chondrules.
>>>>>
>>>>> I'm working on some CR2 slices that need polishing and they won't take
>>>>> a decent polish. I can get the saw marks out, but beyond that I can't
>>>>> get a polish to take. The more I try, it just muddies up the matrix
>>>>> and subdues the features. The metal fleck and rings around the
>>>>> armored chondrules come out nicely, but the rest of the specimen
>>>>> becomes muddy and the chondrules fade into the matrix. What am I
>>>>> doing wrong? This particular CR2 is similar to NWA 801, but a little
>>>>> more weathered. Could that have something to do with it?
>>>>>
>>>>> Do the Hupes have some magic trade-secret technique? Or am I
>>>>> overlooking something obvious?
>>>>>
>>>>> I started out with 320 grit and then progressed to 400, 600, and 800
>>>>> grit - hand sanding, dry, on wet/dry sandpaper.
>>>>>
>>>>> Best regards,
>>>>>
>>>>> MikeG
>>>>>
>>>>>
>>>>> ---------------------------------------------------------------------------------
>>>>> Galactic Stone & Ironworks - Meteorites & Amber (Michael Gilmer)
>>>>>
>>>>> Website - http://www.galactic-stone.com
>>>>> Facebook - http://tinyurl.com/42h79my
>>>>> News Feed - http://www.galactic-stone.com/rss/126516
>>>>> Twitter - http://twitter.com/galacticstone
>>>>> ---------------------------------------------------------------------------------
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>>>>
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Received on Fri 28 Oct 2011 06:26:47 PM PDT