[meteorite-list] RE: RE: Polishing slices?

From: mark ford <markf_at_meteoritecentral.com>
Date: Mon Mar 21 13:24:54 2005
Message-ID: <6CE3EEEFE92F4B4085B0E086B2941B31244D8C_at_s-southern01.s-southern.com>

Yes, I'd like to add to that, always wear a mask when sanding rocks!!!
 - 10,000 miners can't be wrong (mainly because they are dead from
silicosis).


In my experience once you have achieved the desired result, it is VERY
important to clean the surface of the rock, since dust sits in the
crevices and hides the detail. I have often wiped specimens with an
alcohol soaked cloth that have supposedly been prepared by the 'experts'
and found the cloth turned black with preparation dust, only to reveal
much unseen detail on the slice!, so its worth taking the trouble to
clean the rock well after sanding....


Best,
Mark Ford




-----Original Message-----
From: Martin Altmann [mailto:Altmann_at_Meteorite-Martin.de]
Sent: Tuesday, March 08, 2005 12:33 AM
To: Christian Anger; meteorite-list_at_meteoritecentral.com
Subject: Re: [meteorite-list] RE: RE: Polishing slices?

And addition:

Don't forget to clean your fingernails too, if you switch to the next
higher
grid.
A single remaining grain from the coarser powder could disturb the
result of
the next polishing round.
Control with a good magnyfying glass from time to time whether marks
from
the antecedent coarser grains are visible,
if not anymore, you can go on to the next finest grain.
I use also the sand papers dry, but for cleaning the slices between the
switching to the next grid,
I use water or alcool for the more sensible stones.
If water, add a little drop of dish-liquid, and use a toothbrush from
downwards to the specimen - so the loose grindiding grains and the dust
will
fall out and easily sink away from the piece. Dry it shortly.
This wet cleaning is not so problematic, if you continue immediately
with
the grinding as the water will fastly volatilize.
After the last grinding a good test to see, whether there ist some dust
left
in the slice is to wipe the surface with some pressure over your leg,
which
should stuck in a black jeans. You'll see immediately whether it has
some
dust left or not. But don't tell to mommy...

With dry polishing you should use a mask against fine dusts. Cosmic dust
in
the lungs in not so agreeable, especially not the nickle from the iron
meteorites. Those masks aren't expensive and should be found in each
DIY
store. Don't mix them up, with those for only hygienic purposes, those
are
not suitable.

All in all a hard work, but by hand one can produce a perfect polish
with
small means.

Happy working!
Martin

----- Original Message -----
From: "Christian Anger" <christian.anger_at_aon.at>
To: "'Meteoryt.net'" <marcin_at_meteoryt.net>;
<meteorite-list_at_meteoritecentral.com>
Sent: Tuesday, March 08, 2005 12:47 AM
Subject: [meteorite-list] RE: RE: Polishing slices?


> Disagreement !
>
> I also lay the sanding papers on a flat glass which has the same
effect of
> producing a flat surface on the sample. I do not have rounded edges on
my
> specimens.
> Also it is wrong to move the face of the probe in circles.
> You have to describe an "8" when moving the sample across the grains
or
> paper - that's the real polishing technique.
>
> I also do NOT produce scratches. You have to take care not to withdraw
> grinding material from the coarser grinding papers to the next lower
> grinding grain size paper. Keep your sanding papers clean. Store every
> sanding paper extra, be careful and make the job with patience and
love.
>
> I do not have the difficulties what Marcin is talking about.
> And diamond powders or pastes are expensive too.
>
> The technique I use only takes time. I own years of experience in
polishing
> by using sanding paper and I also use it DRY - without any fluid
(water,
> alcohol etc...) - I think nobody expected this - but that's my
experience
> and it works - works very well and I have best results - without any
> scratches. You just have to learn it. Experience is all.
>
> It is a lot of work, for sure, but this belongs to curating a
collection
> too, for me, at least.
>
> Cheers and good night,
>
> Christian
>

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Received on Tue 08 Mar 2005 04:25:01 AM PST