I had this idea for displaying my jewelry using slabs of rock and
so I bought a few. But they were not polished. Can anyone walk me
through how to hand polish these few slabs effectively and
semi-efficiently. My equipment consists of a Foredom and hand
tools. And please, tell me if it cannot be done.
Your fordom is useless for this with any sort of slab bigger than
about an inch and a half or so in size. And even then, won’t do a
good job, since usually one want’s such things reasonably flat.
So you’re doing it by hand. Use successive grits of silicon carbide
wet/dry paper or cloth to sand them smooth, then smoother, then
smoother still. The grade you start with will depend on how flat the
saw cuts are to start. Most likely, you’ll need to start with a 120
or 220 grit. Tape the sheets down to a flat surface to work on. Use a
little water as lubrication, which washes the grindings from the
paper surface keeping it cutting. You’ll need to use successive grits
(ie, 120, 220,320,400,600, etc) all the way down to perhaps a 600
grit. Worn 600 grit is better, and finer grits still, would be even
better than that, if you’ve got it available. Note that this is time
consuming to do by hand. I’d guess that to fully hand sand a normal
sized slab to a reasonably smooth pre-polish might take at least an
hour. Maybe more. Each sanding stage should be done in a direction 90
degrees or so to the previous one, so you can be sure all traces of
the previous step have been sanded out.
Polishing is done on a felt, leather, or even canvas surface, also
affixed to a flat surface. You may need to use contact cement to keep
it stuck down. Use a slurry of water and cerium or Tin Oxide. Not too
wet. Just damp. Again, it can take some time and effort.
Somewhat faster polishing might be achieved with diamond compounds.
Use a canvas surface for the paste polishing compounds. You’ll have
to, as with the wet/dry paper, use successive grit sizes to work up
to a polish. 8000 grit will give an acceptable polish. 14,000 will be
better. Once you’ve got a halfway decent polish started with the
lower grits, finer and finer ones take less time, so it’s worth it.
Now, after you’ve read all the above, and considered that you’ll
have most likely spent two or three vigorous hours on each slab, you
just might wish to consider a much faster, and perhaps acceptable
Go to the hardware store and buy a can of spray clear plastic
coating like Krylon spray. Get the gloss finish, not the matte. Be
sure the slabs are clean, oil free, and dry before you spray them.
The end result will be hard to tell, at least from display case
viewing distances, from an actual polished surface, and it takes
minutes, not hours, to do.
Oh, and in case the above isn’t clear, I’d strongly recommend the
spray. But you asked how to actually polish the slabs, so if you
want, there’s the basic procedure. It does work. Just time consuming
and calorie burning. The larger the flat surface, the harder it is to
polish, so any by small slabs would be a royal pain in the backside
to polish fully by hand. But it IS possible if you want.
The final method might also be worth considering. Find a local rock
shop or lapidary hobby group or some individual lapidary artist or
hobby worker who has a vibratory flat lap polisher. These, like
vibratory tumblers for jewelry items or tumbled stones, polish flat
surfaces with a succession of finer and finer grits, and then a
polishing agent. Every bit as slow, or slower, than doing it by
hand. But the machine can do several slabs at a time (depending on
size), and you don’t need to be there wearing out your arms and
fingers… If you’ve got lots and lots of these things to polish, and
anticipate doing yet more on an ongoing basis, then spend the couple
hundred dollars to buy your own machine. Small slabs (1 to 2 inch
sort of sizes) can be polished in lapidary vibratory or rotary
tumblers as well, if they fit the barrel or tub of the machine. That
then polishes and rounds off the edges and corners as well as the