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This list digest contains the following message subjects:

1. LapDigest News for Issue No. 93 - Mon 12/15/97
2. NEW: Stabilizing Turquoise
3. New: Polishing Ammonites
4. RE: Refurbishing Old Equipment, Revisited
5. FS: Books
6. FS: Bolder opal
7. BIO:Rose McAuthur


Subject: LapDigest News for Issue No. 93 - Mon 12/15/97

It has been a week since the last Digest was sent, and I am
sorry. It has been a hard week and it just was not possible
get it out. For those of you who have subscribed recently,I'd
like you to know that my wife has Alzheimer's, I am her sole
caretaker, and she comes first in my lifa, as she always has.
There are going to be times like these, and I ask you to bear
with me.

I was pretty happy with the two triplet/doublet issues, and
hope you were, too. However, there were very few responses
or new queries, so I am publishing a continuation of how to
refurbish old equipment, a topic we covered a coulple of
months ago. My interest in this topic stems from my feeling
that many neophytes to lapidary are young and struggling, and
have the best chance of getting good equipment by buying used
equipment and refurbishing it. This will be added to the past
thread and the whole will be summarized as a file in Archives.

It is 10 days till Christmas. And it has been 7 months and 10
days since the start of LapDigest. And now 93 issues have
been sent out, and our membership has grown to 680!! Amazing!
Lets all pat ourselves on the back for this - yes, you!! You
were the ones who raised the questions or answered others

So please don't foget to submit any questions you have, for
the next issue!!! List lapidary schools in your region. Send
in your favorite lapidary tip. Send in your biography. But
send in your messages to

Drive carefully, stay safe, and I hope your life is peaceful.
Don't forget to hug those you love, and enjoy every hug you


Subject: NEW: Stabilizing Turquoise

Does anyone know how to stabilize porous turquoise? Any help
on this subject would be really appreciated.
Pat Donnelly

-non commercial republish permission granted-

Subject: New: Polishing Ammonites

Hello, list members! I have some Russian ammonites that have
been polished on one side, and since the replacement mineral
is either pyrite or marcasite, the polished surface when I
bought it had a mirror finish. Since then, the surface has
tarnished to a gun metal grey color. Does anyone know of a
means to polish the surface back to the original finish,
without using diamond wheels? I have tried ultrasonic
cleaners to no effect. I have a clear coating to protect it
from re-tarnishing, but I need to get the shine back first.
Thanks for any help.

Vance McCollum

Subject: RE: Refurbishing Old Equipment, Revisited

This issue will include, again, advice on refurbishing old
lapidary equipment. We had an issue devoted to this some time
ago (in Issues 60,61,63,64,& 65), and my reason for interest
in this area is that newcomers to the hobby may not be able
to afford new equipment. Refurbishing second hand equipment
is a cheaper alternative and the equipmment WILL get the job
done. So here is more advice, which I hope will be useful to

I sent a note to several places on the web with the following
request included:

<<The question is: When you buy a piece of used equipment and
want to refurbish it, what is a good strategy to use? Strip
it completely apart? How do you deal with rust? How can you
tell if bearings are bad and need replacing? New belts? New
pulleys? What kind of paint will stand up to shop usage?
Would you please talk a bit about how you would go about
rebuilding equipment?>>,

and got the following replies:

Hale, I would check the bearing for looseness and smoothness
of operation before pulling them apart. If they are tight and
smooth running then leave them alone. You can only hurt them
by pulling them for cleaning. Most of those bearings are
lifetime lubed, so you can't do much with them anyway. If
there is a place to lube them just be sure you clean off all
the grit prior to pumping grease into them. You are working
with silica "saw dust" and it will do a job on bearings real

If there is play in the bearings, by all means pull them out
and replace with sealed, lubed, bearings. The body of the
grinder/saw will need to be cleaned of rust and repainted. I
use a small sand blaster to clean rust if its a big job.
Otherwise I just use my power wire brushes, scrapers, etc.,
to get down to clean metal. For most of my equipment I use
"Rustoleum" paint. I like the combination of the "Rusty metal
Primer" and immediately spray on the top finish coat on top
of the still wet primer. It is an almost bomb proof finish.
I had it on two tow hooks on my pick up that were exposed to
the fly grit and water from the tires and it lasted more than
ten years! The most important part is the prep of the surface
before painting. Get it clean and FULLY degreased.

If you have a really tough job for the paint, you might want
to think about something like "Amron" paint, but it is very
expensive and requires baking I believe. It is almost totally
impervious to everything though when properly applied. You
won't need to redo it in the future.

Other than that, I can't think of much else to add. You
might need to change out the split nut on the rock saw table
drive and/or the feed screw. By the way, it has been shown
that there is little or no advantage to using soluble oil in
your saws over clean water unless the screw feed requires it.
It shouldn't if the split nut is bronze or brass. The liquid
acts as a coolant, and not as a lubricant. As a geologist I
have had to maintain BIG rock saws on some of my jobs where
we had to saw lengthwise thousands of lineal feet of core we
had drilled. There was no advantage to oil in the tub. In
fact it just makes things messy to work with. We didn't use
an enclosed tub saw though, but a saw of the type brick
masons use, since the enclosed tub types are so horribly
slow. We needed production in our work. I had one young
fellow hired to do nothing but cut core all day...... talk
about a miserable job! :-(

The one nice thing about the equipment you are talking about
is that its all very low tech, and low precision. If you get
involved with laps and faceting arms and such that is a
different matter. A saw is a saw, and it is easy to maintain
for the most part, same with grinding arbors.

You are welcome to cross post this, but I doubt it has
anything worth the trouble in it. <grin>

I hope that helps.

Ron Reil
In rec.crafts.metalworking, under the title: cleaning
used machine tools, John Bing <> asked:

<I have a number of pieces of older machinery i.e. Bridgeport
Series 1 Mill, Southe Bend Lathe, etc. My question is what
is good for removing accumulated grime and crud? I have a
friend that soaks large assemblies in sodium hydroxide (lye),
but that is a little severe if it is not necessary. Also
what is necessary for prepping the surface, after cleaning,
for painting? What is a good machinery paint?>

Try Castrol SuperClean (available at K-Mart, Wal-Mart, etc.)
Spray it on, give it a couple minutes, wipe it off.
Dissolves old grease and oil better than anything else we've
tried. Beware - if you leave it too long it will attack the
paint (fades it quickly). Wash it off with water when you're
done. As far as paint goes, any good oil based paints will
work fine (try RustOlium in Machinery Gray). Poly paints and
epoxies are better but more expensive. Lacquer is OK (dries
really fast) but stains from some coolants. Surface prep is
always a pain. Clean, scrape, sand rough edges, prime with
high build auto primer, sand again, wipe down, paint twice.

Bob Bain
We are a small precision machining shop, and while we don't
use lapidary equipment, whenever we buy a machine, ESPECIALLY
if the previous owners used water or water soluble fluids, we
strip it down to the frame, or as close as we can get.

We use oils, kerosene, WD-40, or whatever is handy, and
steel wool, scotch-brite, or whire wheels to remove rust on
ways, ball screws, and working surfaces. We only replace
bearings when the machines run out of tolerance (check the
manufacturer for allowable specs).

Feel free to use this ;-)


Tom Accuosti
Precision Methods
Wolcott, CT
Regarding rust-
No matter how much you try to clean off rusty metal, "seeds"
of rust will always stay under your paint to fester. A number
of products on the market address this. One name that comes
to mind is "Extend" but there are others. You just remove the
flaky, loose rust and grease, dirt etc. and spray it on. It
chemically changes the rust to an inert black coating which
can be painted over and won't rust thru.

Carl S.
Still regarding rust -
Another such product is "Rust Converter" from Gempler's, an
agriculturally oriented calalog sales outfit in Wisconsin.
To quote: "Chemically converts rust to an inert, black,
protective barrier that you can then paint over." This stuff
works! It is also cheaper than some of the other similar
concoctions. It comes in larger sizes than others as well.
Quarts are $9.95, gallons are $34.95, and 4-gal cases are
$119.80. A gallon covers 500 sq ft. That's a lot of
blacksmithing gear, folks! Requires 2 coats if not to be
painted, though.

211 Blue Mounds Road
P.O. Box 270
Mt. Horeb, WI 53572


I have no association with Gempler's other than to have used
this stuff.

Glidden has Stuff called OSPHO, ( I think this is how it is
spelled ) does the same as is explained above but cost about
$16.00 a gal. I have used it and it does a good job.

Marrin Fleet
And from rec.woodworking, v. dickinson wrote:

<<Any suggestions on the best way to remove rust from the
surfaces of table saw, edge planer, etc.? Rust is caused by
a combination of lack of use and fumes from a kiln.>>
Chris Dickinson>>

The best all around tool is the "Fine" grit wonderbar. This
is like a large rubber eraser with a very fine grit embedded
into it. I think that Klingspor abrasives calls it a
Sandflex Abraser.

The grit is fine enough that it tends to put a smooth polish
on cast iron and steel rather than eroding the surface of
your table. It will actually improve the surface of most
tables with a factory ground finish.

Works great on rusty tools also--I use it as a hone to give a
quick edge touch up on my "rough use" chisels.

Cost is about $ 4.00. I have seen them in many woodworking
catalogs. They last nearly forever. Once you use one, you
can't live without it.

Nuf said...

K. Miller

Thomas Bunetta <> wrote:
<<I've been wracking my little old brain, but cannot remember
the name of the stuff, but any marine supply should carry
it. Paint it on, wait a while and where there was rust is
now a black coating that is supposed to be a protectant from
further rust. I don't think it would be a good idea to use it
on table saw tops and similar, but the bolts and nuts, etc.
of stands and enclosures might be good candidates.

I used to get a surface preparation called OSHPO from the
Sherwin-Williams paint store that did the same thing. It was
used as a surface preparation for clean or rusted ferrous
metals. It turned any oxidation black and the surface was
ready for painting. I don't know how it would work on cast
iron equipment but it was a great rust preventive.

Mark Middleton

Subject: FS: Books

We have the Opal Cutting Books:

1) Opal Cutting Made Easy- P. B. Downing $5.95
2) Opal Identification and Value- P.B. Downing $38.95
3) Opal Adventures- P.B. Downing $19.95

Go to BOOKS and then GEMSTONES, or write us at the
address given below.

Thanks BETTY and RUSS

Subject: F/S: Bolder opal

For sale: Bolder opal, have only one lot 148 grams. lot
consists of trimmed pieces in assorted shapes and sizes, all
are appox 3-6 mm in thickness,couple thicker.... all need
final polish and trimmed. Excellent for inlay, channel work
in rings earings etc... The lot for sale at $450.00 plus s/h
Thanks and best wishes

Gemstone Brokerage Associates Ltd. Telephone (518)438-5487
P.O. Box 8930 Albany, N.Y. 12208

Subject: BIO:Rose McAuthur

Hi; I am interested in all types of lapidary work. Rock
hunting was one of our chief forms of family recreation when
I was a teenager in Weiser, Idaho. Learned some lapidary on
a small Sears and Roebuck machine with a horizontal lap.
Majored in geology years ago, but had a couple of children
instead of finishing up my degree. After raising six
children, seven years ago my husband and I joined the San
Francisco Gem and Mineral Society. I became proficient
enough there to get my novice(?) certificate and became an
instructor in the shop.

When my husband retired three and a half years ago we moved
to Idaho and brought with us a ton of rock and a collection
of second hand lapidary equipment. The two biggest challenges
we face are finding the time to work with rock and keeping
our second hand equipment in running order. Right now we have
a flat lap that needs a split phase motor and a thirty year
old grinding unit that we are having trouble disassembling
to add a new 100 grit grinding wheel.

Looking forward to the digest!

Rose McArthur
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