[meteorite-list] Need some help with chondrite preparation.

From: Kevin Forbes <vk3ukf_at_meteoritecentral.com>
Date: Thu Feb 23 03:05:04 2006
Message-ID: <BAY113-F3813F1A400C21815CC123099F20_at_phx.gbl>

Gday Mike, probably what you want, is the same as what I want, a flat lap,
this is a disc that rotates like an old vinyl LP. You can get them from eBay
in various grades of diamond grit, you of course need the flat lap machine
to drive them, or make your own. When you are done grinding out all the
cutting and other marks down to say a 3000 grit, then change to a polishing
lap and use tin oxide or cerium oxide powder, or use a special diamond
polish lap pre impregnated with diamond dust.

Failing having a flat lap machine, try what I use at the moment. I used to
have jars of loose grit and use them on a sheet of thick glass, start with
the coarse first and work your way finer and finer, every time you change
grits, everything must be scrubbed like in a hospital to make sure NO coarse
grains are left to scratch your next stage finer grind or polish, otherwise
its, back one step and then continue. Scrub the stone you are polishinng,
the glass and your finger nails too.

I ran out of loose grit a while ago, I am unable to source any more, so, I
am using at the moment, Wet and Dry paper with the sheet of glass
underneath, I don't know if it has the same name overseas, grit paper maybe,
it comes with all the various sized grits impregnated onto it. Used mainly
in the automotive paint industry. Sizes of grit, e.g. 80, 120, 240, 300,
600, 800, 1200, 1600, 2400, 3200 etc, etc 80 is very, very coarse, 3200 is
super fine, pre polish size grit. Try not to jump too far between grades as
it will take longer to polish out the scratches from the previous step. If
you can't find tin oxide or cerium oxide from any lapidary suppliers (rock
polishers) try good old toothpaste, for a polish paste, or a substance known
as rouge, which is basically Iron Oxide. When moving the stone over the
glass with the grit or polish. Also, when moving the stone over the grinding
medium, move it in a figure eight (8) otherwise you will end up with bevels
on your supposeddly flat stone. If you move it in figure eights, it will
come out dead flat. One more thing, while doing it all manually, put some
elbow grease into it, press hard, make sure it is wet. Some people use oil
instead of water, up to your preferences.

I hope that has been of some help mate.

Good luck. Yours faithfully, Kevin Forbes. VK3UKF.




> Hello all, I am working on some slices of the new Arizona meteorite. Warm
>Springs Wilderness, it is an H4-6 genomict breccia S2 W1. I am cutting the
>slices with a small diamond blade, but do not know how to sand them to get
>the interior to look its best. I would like to hear about how your
>procedures to get them prepared for viewing. Thanks for your help
>
>Mike Miller // E-Bay flattoprocks
>Website // www.meteoritefinder.com
>
>Mike Miller 230 Greenway Dr.. Kingman AZ 86401
>
>
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Received on Thu 23 Feb 2006 03:04:57 AM PST