Edited and Published by Hale Sweeny
Web Site:
Associate Editors: Geo. Butts, JR Shroeder, Steve Henegar
and Margaret Malm

This list digest contains the following message subjects:

1. LapDigest News for Issue No 237 - Fri 10/8/1999
2. NEW: Garnet Changes Colour
3. NEW: Tumbler Linings
4. NEW: Tumbler Linings
5. RE: Home-Built Tumbler
6. RE: Mineral Oil As A Saw Lubricant
7. RE: Notes from Lightning Ridge
8. RE: Need Help with Carving
9. BIO: Harry Bruntz
10. BIO: Wendy Ryder
11. BIO: Jack Nelson
12. BIO: Carl Mauritz
13. SHOW: Announcing the 1999 Jade Festival
14. FS: Cutting & Carving Material
15. WTB: Rough in Minneapolis


Subject: LapDigest News for Issue No 237 - Fri 10/8/1999

Cheryl Hahn of the Castro Valley club wrote saying that
their website is now up, and inviting all to come visit.
The URL is

Becky Salon ( writes that she would:
"be especially interested in hearing from women lapidaries
who read this publication!"

We received a number of messages this week which were out-
side the scope of the list, and which were sent back with
regrets. This Lapidary List will focus on the cutting,
carving, knapping, shaping, polishing and assembly of rocks
or minerals into cabs, special shapes, intarsia and channel
work pieces. Tumbling, slab and trim sawing, the properties
and types of materials used in our lapidary work, and the
treatments of these materials are all proper topics for
discussions on this Digest List. We also include & welcome
BIOs, FS (for sale), and WTB (want to buy) items. We now
have grown to almost 1800 members, and the queries and
responses have grown accordingly. Very soon, we may have
to reject some messages, as the Digest just gets too long.
So if yours is one of the rejected ones, I am sorry. If we
put out the Digest more frequently, we would not have to
reject any of them. The former editor of Facetor's Digest
tried putting out an issue every day, and he recently had
to give it up - I think the stress was too much for him
and I know it would be too much for me!! So we will stay
with two or maybe three digests a week, and if we have to
cut, we will cut the non-lapidary messages. So be it!

Have fun, guys!!


Subject: NEW: Garnet Changes Colour

Can someone please tell me if it is possible for Garnet to
change from its usual red brown to purple blue just by
being cut and faceted/made into a cabochon?


Subject: NEW: Tumbler Linings

>From time to time I have posted thoughts on tumbler linings.
My day job involves working with 2 component polyurethane's,
specifically elastomers (I'm an engineer working on the
design and development of metering and mixing equipment for
two part urethanes)

One of the industries I work closely with is the vibratory
finishing market. Mass finishers use for deburring/finishing
of about any thing you can imagine from arms suppliers,
automotive, industrial, medical, etc., etc., etc.

Some of these machines are in excess of 100 cubic foot
capacity, in addition we work with large tumblers, and
centrifugal machines. About 80% of these machine do use some
type of ceramic media that may be doped with AlO3 of SiC. It
is common for these machines to run in excess of 20,000
hours before relining. For the most part these machines are
just big rock tumblers and vibe finishers. It is amazing how
much more abuse a seemingly soft material can take over say
a steel bowl.

The state of the art for lining would be two part TDI and
MDI urethanes, In the old days it was very common to use
vulcanized rubber, i.e., neoprene. Commercially this is
applied at the compounder then Vulcanized at 260° F, 15 psi
steam for several hours. We still run across applications
that for what ever reason still perform best with neoprene,
and still have it applied from time to time.

So if I had to make a tumbler or need to reline my old
Scott-Murry I would use urethane (70-80 Shore A), but
unfortunately this is a commercial product. If anyone is
really interested in having a lining done drop me a line.

A low budget solution would be to build a metal tumbler with
octagonal internal sides and line the thing with neoprene. I
would buy sheet stock then glue it up with contact cement
(really clean up metal and roughen the neoprene with
sandpaper) then go back and caulk up the joints with RTV
silicone, be sure to overlap the joints with respect to the
rotation of the tumbler, to reduce lodging of materials in
the joints.

I hope that this may help to address some of the discussions
about building tumblers and wear rates of typical linings.

Jeff in Kalamazoo

Subject: NEW: Tumbler Linings

Hi Hale,

Teresa was asking about tumbler lining:

<<... take the tumbler to a shop that sprays "Tuff-Cote"
or similar bedliners onto trucks and ask them to line the
tumbler....>> (See Msg #88 in Issue 236)

I had the same thoughts about the resiliency of the material,
so I bought a quart of the stuff at an automotive paint
supply store. It is made by Morton, and is called urethane
truck bed liner. It cost about $70.00 for a quart with
hardener. You can spray it, roll it, or brush it. The thing
you can't do is breathe it. It can kill or do serious
nerve damage, neither of which sounds like fun.

I will test it over the winter and let you know...

Bob Braun

Subject: RE: Home-Built Tumbler

On is a tumbler with
specifications, built with a used car tire.

Good site.
Have fun!
Jan (swedish for John)

Subject: RE: Mineral Oil As A Saw Lubricant

Hale and Subscribers:

I have been reading with interest your comments on saw
lubricants. I need as much information as possible before I
try mineral oil in my 6" trim saw. When I purchased my Star
Diamond Combination Unit, the dealer gave me Pella oil for
the trim saw lubricant. I found that I couldn't tolerate
the smell of the Pella oil, which also ruined the clothes
and coverups I wore while cutting rock. This was a totally
frustrating experience.

I then tried olive oil, which didn't seem to be a good
lubricant from the standpoint that it heated up while
cutting through a stone. I left it in the saw tub for
quite a while and it didn't go rancid, mainly I think
because the machine sits in my cool basement, in a room
which has a dirt floor.

Since I don't think olive oil is a good solution to the
problem, I'm willing to try mineral oil. Has anyone tried
it? Will it work better than olive oil? How does it
compare with Peanut Oil? Will the cheapest SAE monograde
5 or 10 oil (non-detergent) you recommended facilitate
cutting without heating up? What kind of a product is this?
Would I find this at a Wal-Mart?

Becky Solon
East Stroudsburg, PA
Becky: For a trim saw of 6" or 8", unless you are cutting
very hard material, you can use water as a coolant safely.
Just don't force the material through the saw too hard. And
clean up every night to prevent rust. You can use a rust
inhibitor (see any good lapidary catalog) to help prevent
rusting. hale

Subject: RE: Notes from Lightning Ridge

hi hale and friends,

Today I remain on subject: cutting at the ridge. 95% of
commercial opal cut here is oval and cut with diamond
abrasives on large diameter shaft accurate twin 8" head

Polishing is on felt or chrome suede leather, and cerium
oxide on lapsa (50,000# cerium oxide) is the polish of

For boulder matrix, people use tin oxide or something soft
to avoid undercutting the opal at polish stage.

You can always tell a ridge cut stone because we dome the
backs. We do this because most of our stone goes to Japan;
they demand an open back setting. There is a little more
weight loss like this, but the setting becomes much easier
as will become evident below. A variety of cabochon
variations are cut here, but this slightly domed back is
our hallmark.

The latest talk at our last opal expo was free forms.
There are a lot of younger people in the industry now, and
our traditional market base is swinging away from Japan and
to North America. thus our style of cutting is starting to
be influenced by this. i must hasten to add that top gem
material has usually been cut free form in the past. it is
strange but true that carving style has only been widely
adopted in the past 3-4 years. While it is the norm for
Queensland boulder, here it was formerly put over the saw
to get 100% convex face for ovals.

A simple open back setting for opal: measure, cut, and hard
solder metal bezel sheet stock as for a box back setting.
Fit resultant oval ring onto a round mandrel. Note inside
diameter. Wind .7-1.2mm round wire to this id. Cut and fit
this wire bearing or seat to fit snugly inside the bezel;
sweat solder using minimal medium solder. Stretch the round
seat to oval from the id using round pliers; voila the stone
seat. If you are working in gold, this is very conservative
of material.

Once you make this style of stone and seat, you will never
use anything else. Stones do not rock in the seat when
setting, no fillers or backing are required and if the bezel
edge is a little higher, the additional protection is
welcome with opal and other soft stones. This is a very
secure setting.

Hope the foregoing is of interest to your members,

regards to all,

james dumar

Subject: RE: Need Help with Carving

Tam, you can get a nice set of polishing wheels from HiTech,
the diamond people. They are located in Simi Valley CA. You
get some arbors and a half dozen diamond pads per mesh. You
get four meshes from 250 to 14,000. I use the half inch size
for fire agate. The kit costs only $10.00 or more for
larger pads. BTW, you get a dozen of the final polish pads.

Their number is 805-522-6211

Peter Plantec
Creative Director
Virtual Personalities, Inc.
Beverly Hills, CA

Subject: BIO: Harry Bruntz

Hi everyone, I have been a rock collector and cutter for
the last 49 years. I currently live in El Paso, TX.,
originally from central NJ. My interests center in
collecting, cutting, carving and jewelry making, but if a
pretty rock, fossil, or mineral comes along, it will be
picked up. I have a collection that has outgrown my ability
to keep it and have a list of materials for sale. This
weighty collection is in the neighborhood of 40 tons. It
is the result of collecting, collection buying and trading.
It is less than a ton per year of acquisition, not too bad.

For a list email me.

Good hunting and cutting.


Subject: BIO: Wendy Ryder


I am a newcomer to the jewelry making business. So new that
I am still shopping for classes to take and tools to buy.
I am hoping that by subscribing to this digest I will gain
the knowledge I need to get started and to continue a career
in the business. I am very excited starting a career but I
do have one question....I would like to start out repairing
and making others design until I get really comfortable at
it. Would I be able to support myself financially by do
I would love to work for a jeweler now doing these kinds of
jobs. What is the career and financial outlook. I only ask
because I will know whether to keep my present job and just
work part-time or to make the leap to full time.

Thanks for your time and please place me on the mailing list.


Subject: BIO: Jack Nelson


My name is Jack Nelson and I live in San Cristobal de Las
Casas, Chiapas, Mexico. I own a tour guiding business here
and also export Chiapan amber. I have not been working the
amber up until now, just buying and reselling raw and
polished amber and amber jewelry, but I want to get into
the working of amber and because of that I have subscribed.

Jack Nelxon

FREE subscriptions to The Mexican Travel Newsletter
Mexiculture: Tours | Folk Art | Amber
Tel 011 (52) (967) 80101 (from the USA)
Fax (630) 839-4180 in USA; (967)80101 in Mex.

Subject: BIO: Carl Mauritz

Hello Every One,

I'm new to the list here . My Name is Carl Mauritz. I live
in Tigerton , WI.

I just bought a complete lapidary set up with materials to
cut and cab the material that I collected the past 6 years.
It came with a cab machine ( I haven't found the brand name
on it yet), two saws, a tumbler, ect. Lots of material too.
It cost me $1,500. for every thing.

Now my fun begins cabbing . Talk to you later.

Sincerely Yours
Carl Mauritz

Subject: SHOW: Announcing the 1999 Jade Festival

The Annual Jade Festival will be held at Pacific Valley
School on October 8, 9 & 10. Jade Festival hours are
Fri: 12 noon to 5pm, Sat and Sun: 9am to 5pm. Saturday
night will feature a party and live band. BBQ food is
offered each day so you do not have to pack a lunch or
dinner. There is no admission charge. Proceeds from the
BBQ go to the local community.

Pacific Valley School is one driveway north of Plaskett
Creek Campground. Plaskett Creek Campground is a National
Forest Campground and is located approximately 57 miles
South of Monterey on Highway 1. There will be signs on
Highway 1 so you can't miss it.

Carol Bova

Subject: FS: Cutting & Carving Material

I have the following for sale: Alabaster, Travetine, Fossil
Horn Coral in Gray Matrix, Selenite, Rhyolite, Pink Talc
carving material, uncut Geodes and Solid Geodes

Please email me for a complete list of prices & materials.

Harry Bruntz

Subject: WTB: Rough in Minneapolis

Dear Hale, I will be visiting Minneapolis next month and
will be looking for rock shops in the area. I have tried
looking through phone books at the library and haven’t found
any. Does anyone know of any shops or people in the area
with rough cutting material?
Suggest you check the 1999 Lap Journal Buyer's Guide, which
lists shops by geographical region. This should give you
a list of all shops in Minneapolis area, with some info on
each shop! Have fun!! hale
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