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Equipment for Polishing opal


#1

I recently bought a lot of Lightning Ridge Black Opal rough and
would like to experiment with cutting, polishing, shaping and possibly
inlay. I have searched the web and thumbed thru all my tool catalogs.
I am not happy with the equipment that is available because of quality
vs. price. I am completely new to lapidary, the processes and
equipment. Can anybody make any recommendations on the type/brand of
equipment that I should be looking at. I have not ruled out making my
own equipment since I am a tool and die maker by trade. I would just
need a rough plan or concept preferably for a versatile piece of
equipment. I should also point out that I am waiting for 2 books
recently ordered, Black Opal - A Comprehensive guide to cutting and
orientating and Opal Cutting Made Easy, hopefully they will shed some
light as well. A thanks in advance and overdue thanks to all orchidians
for your generous sharing. Steve D.


#2

Steve, If I were starting out and wanted a good machine that would
come close to doing it all, I would buy one of Diamond Pacific’s
machines. The 6 inch machine, Genie I think, is probably the best
one to go with. The machine comes equipped with all the wheels
necessary to do opals and most other Draw backs are
expense and wheel life. For opals the machine should last a long
time. If you start doing agates, jaspers, or jade you will wear out
the wheels very quickly.

Gerry Galarneau


#3

Steve D. There is a very compact unit by Hi Tech of Simi Valley, Ca.
called the “All You Need” that is perfect for Opals as well an most
other stones. It comes in both 6 and 8 inch sizes. You will find it
very compact and easy to use wherever you may want to work stones.

There are several flat laps of varying diamond grit which are very
easy to change. The cost is realistic. There is an 800 number, and
usually an ad in Rock and Gem magazine.

As it is basically a flat lap, it is easy to get a level surface for
setting and/or quartz capping.

Hope this helps, the Opal classes I took were using this machine.
Teresa


#4

Both excellent books for gaining insight into cutting opal! But some
basic hands on experience wouldn’t hurt either. You might check out a
local lapidary club to see if they have a workshop or a member or two
who could show you the various basic equipment in action, and give
you a chance to try it out yourself. For an intro to cabbing, check
out Dick Friesen’s article in the archives of the Eclectic Lapidary.
http://www.bovagems.com For more info on opal, check out the American
Opal Society’s website: http://www.opalsociety.org

HTH,
Carol

Carol J. Bova
@Carol_J_Bova
Laguna agate and other lapidary rough
http://www.bovagems.com The Eclectic Lapidary


#5

In my early 20s I started messing with opal rough, and have continued
now for many years. When I was young and broke, I worked opal in
extremely low tech ways.

If you have a flex shaft machine, you can use a diamond or corundum
cut-off wheel to cut stones to approximately the shape you want.

Mount the piece of rough on the end of a length of 1/4" dowel. You
are supposed to do this with dop wax, available through a jewelry
supply, but failing that you could use sealing wax of the sort often
sold in craft stores.

Using the dowel as a handle the stone is easy to manipulate and you
can cut it and shape it with the cut-off wheel. A word of caution:
opal is a silicate, so you don’t want to be breathing the dust. Keep
the work wet so there is no dust and wear a mask anyway. Keeping the
work wet will also keep it from getting too hot which can easily
damage the stone.

Once the stone is roughly the shape you want, you can continue
shaping and polishing using wet/dry sand papers. Start with 180 or
240, and work your way stepwise to worn 600 grit. If you are able to
get 5 micron or even .5 micron abrasive sheets you will be able to get
a much higher polish than with 600 grit.

This is a low tech, slow speed method, more suited to hobbyists than
production work, but it will allow you to start on a minimal budget
and give you the opportunity to get a feel for what you are doing. If
you are pleased with doing it you can work your way up to less labor
intensive but more expensive methods. I would also strongly recommend
looking at Lapidary Journal. Every once in a while they have an issue
devoted to opals and in general they have lots of good info.

Hope this helps. MP


#6

Dodge, Steven M. wrote: I recently bought a lot of Lightning Ridge
Black Opal rough and would like to experiment with cutting, polishing,
shaping and possibly inlay… . . Can anybody make any
recommendations on the type/brand of equipment that I should be
looking at.

yes: I started cutting opals approx 20 years ago. I think there are
two ways to go. I love my genie (Titan) if you are sure you will cut
a lot of stones. (Pixie if you aren’t sure, or can’t afford one of
the larger machines.)

the other way is an arbor with a grinding (diamond) wheel and an
expandable drum (one or more) used with diamond belts; and polish
with diamonds.

good luck. like anything it is easy to do; hard to do well.
gregor


#7

Steve, I think the advice in the previous letters is all good,
however, since you are new to the lapidary side of things, I would
advise this: before you start grinding away on your lightning ridge
rough, learn to cut a cheap stone first. cut a few agates, turquoise,
jaspers, etc. Learn the proper sanding sequence and how far to go
with each grit, how to eliminate “flats”, how to put a polish on a
stone while keeping it cool,(wet).i.e. the “basics”

While opal is not difficult to cut, it is very easy to waste.Although
you may still come out with some good stones, you will probably not
get as good of return from your parcel as you could.Being a
"dyed-in-the-wool" opalholic myself, I hate to see good rough wasted.
Lightning Ridge can sometimes be rather tricky to cut- study each
piece carefully before putting it to the wheel. Many times the best
color is just under the potch. As far as equipment goes, the "pixie"
and the “genie” are both good machines. The “All-u-need” by Hi Tech
Diamond is what I use to cut flat backs and pieces for intarsia and
doublets. For most of my cutting I use a Highland Park 6 in. combo.
It was a sad day in lapidary when they closed down. If you can find
one used - JUMP ON IT - it is one of the best machines ever built!
enough of this rattling on , if I can be of service contact me off
list. Later,

Mark Thomas Ruby
SunSpirit Designs


#8
    In my early 20s I started messing with opal rough, and have
continued now for many years.  When I was young and broke, I worked
opal in extremely low tech ways. 

I just want to add to Michael post. I use his method to teach any one
that want to cut and polish any stones and who do not want to invest
in lapidary equipment. I have not found a stone that it does not work
on, but I believe it is one of the best way to cut opals, if your
cutting them for yourself and not mass cutting.

I also teach to just use a grinder from the hardware store for
grinding nearly every stone, including opal, to shape before going to
the sandpaper. YES, a water system must be used, I have my way of
doing this, but nearly everyone can figure out a way to put some sort
of water drip system on the wheels for safety and for keeping the
stones cool. Wear a good dust mask too, if you wish, or for sure if
you smoke.

To put a good polish on opal, and even chip inlay, I teach use a
piece of leather (A belt blank from a leather store is great, but any
unfinished leather piece is ok.) to polish. It is so simple that it
really upsets the students that have thousands of dollars in equipment
at home. Especially those that have cut a lot of opal, because it does
not have any chance of heating the opal, or putting a "egg shell"
finish on it and other softer stones. It works great with jade too.

Just soak the leather in water for about five minutes, then wet and
dip you finger in Linde A (a polish compound that is available from
nearly every lapidary supplier) and apply it to the leather. If your
afraid of getting stuff on your fingers, wear a rubber glove, no
problem. Use the smooth side, not the suede side. I am not that
familiar with leather terms, and do not care to learn, but there is a
smooth side and rough side, use the smooth side. It is a powder and
you should add enough to form a light paste on the leather.

Then just take you dopped stone and start rubbing it back and forth.
You will be amazed at how fast this method works. I thought that it
would take forever, when I first came up with it. The first time I
tried it, was actually during a class for my silver students. I told
them it was an experiment, and that it would most likely take a lot of
time, but better than spending hundreds for a lapidary unit if they
were not seriously interested in lapidary. I told them check with me
as they progressed to a polish, if there was a polish. In just a few
minutes, less than five, one student brought up their opal. I said,
“No you will need to work on it longer than that!”. She said, “Well,
just look at it!” I was shocked to see one of the best polishes on
opal than I have seen with any ones method and thousands of dollars
worth of equipment.

Give it a try, it will only cost you about $8.00 for the Linde A and
about $2.00 for the leather! I have not tried tin oxide, but I bet it
will do the same. My students have had great success with opal,
malachite, turquoise, petrified wood, dinosaur bone, sodalite, lapis
(great polish!), blue lace agate, tiger’s eye, and leaverite.
Leaverite is those stones you find that you should just leave right
where you find it! But they had fun cutting them.

Don
http://www.frii.com/~dnorris