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

From: Michael Gilmer <*meteoritemike_at_meteoritecentral.com*> Date: Fri, 28 Oct 2011 23:02:35 -0400 Message-ID: <CAKBPJW9hBgmcZJz=Y4Mws_BSUAY-KipeR0FnY=Uj51dAM9+5gQ_at_mail.gmail.com> · meteoritemike_at_meteoritecentral.com

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Galactic Stone & Ironworks - Meteorites & Amber (Michael Gilmer)
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On 10/28/11, MexicoDoug <mexicodoug at aim.com> wrote:
> Hi Mike,
>
> Trade secrets to sanding?  Maybe you mean just the experience of
> knowing each meteorites favorite way to be sanded.
>
> It's kind of silly not to use deionized water to wet sand the specimens
> that you've determined look better that way unless we're talking about
> a stone that's never slept outside over night, if you can dry them
> after quickly enough.
>
> I appreciate your perfectionism of not wanting to allow water to touch
> your meteorites, but stony meteorites are like sponges anyway and soak
> up water.  Dew tends to form on them inside your house if you're not
> careful or outside and they are porous, and once out of the oven will
> always be picking up water - they absolutely don't stay dry.
>
> All of the desert specimens which have been in the desert got tens,
> hundreds and thoudands of years have the unstoppable phenomenon of
> terrestrialization; that is dew cycles more than half of the nights,
> each night, every day of every year.
>
> The desert is especially prone to dew on meteorites, even though it is
> so arid it is another of those conundrums - why so much dew in the
> desert?  Simple ... the meteorite is cold as stone in the morning and
> that is the time everything is the desert has most likely settled down
> in terms of winds which are what would normally wisk away the humid air
> before it cooled enough to deposit its dew.
>
> The core of the meteorite continues cooling the immediate air around
> the meteorite (this is infrared heating/cooling) faster than the
> radiative heating of the Sun can warm, so the go dew-dew on the
> meteorites all the time.  This is accentuated by passing through the
> dew point of the air almost always in the desert due to the extreme
> day/night temperature variation, remembering even the dryest desert in
> the world has a lot of water still in it.  The result is drplets of
> water all over the meteorite which collect and rust below it sometime
> for a long time.
>
> People in some places supposedly in the Atacama in prehistoric times
> used to pile up rock just to collect the water in them.  Stone castle
> walls can have the same effect.  In China, desert farming is
> accomplished by scattering gravel on the ground to take advantage of
> this and no additional irrigation is necessary in some cases.
>
> If you really are making a business of this and find yourself
> evaluating a capital purchase of costly equipment or holding off for
> the time being - and as posted want "diamond" sandpaper without having
> to buy a motor and disk or ready to use laping machine, and to do it by
> hand, there is no reason that you can't put nearly an equal finish on
> it over glass while purchasing the same polishing grit for the final
> step and impregnating it on some sort of shammy that you can be sure is
> clean of prior hard particles, exactly as you have been doing, wet or
> dry whichever works best for the piece.  Of course 3360 rpm of a 6"
> diameter wheel at the edge will be traveling exactly a mile a minute
> worth of arm strokes.
>
> Kindest wishes
> Dioug
>
>
>
> -----Original Message-----
> From: Michael Gilmer <meteoritemike at gmail.com>
> To: Count Deiro <countdeiro at earthlink.net>
> Cc: meteorite-list <meteorite-list at meteoritecentral.com>
> Sent: Fri, Oct 28, 2011 5:55 pm
> 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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