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 <meteoritem...@gmail.com>
To: Count Deiro <countde...@earthlink.net>
Cc: meteorite-list <meteorite-list@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
--
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Galactic Stone & Ironworks - Meteorites & Amber (Michael Gilmer)
Website - http://www.galactic-stone.com
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On 10/28/11, Count Deiro <countde...@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@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
--
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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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On 10/28/11, Ed Deckert wrote:
Hi Mike,
Perhaps the Hupé'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
-------------------------------------------------------------------------
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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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