LAPIDARY DIGEST
Administered by Hale Sweeny (hale2@mindspring.com)
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This list digest contains the following message subjects:

1. LapDigest News for Issue No. 118 - Wed 2/25/98
2. NEW: How Do I Cut A Cat's-eye Chrysoberyl
3. NEW: Criterion or Gemking Saw Blades
4. Re: Treating Bisbee Malachite-Azurite
5. NEW: Dopping Opals


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<MSG1>

Subject: LapDigest News for Issue No. 118 - Wed 2/25/98

Well, we thought we would take in the Jackson, Miss. gem
show this coming weekend, so we will be away for a few days.
This means that the next issue will probably be published
about one week from today. But the computer will be left on
so the archives are still available to you.

I don't know about where you live, but here it is sunny, 74
degrees, the daffodils and crocuses are blooming, and it is
beautiful outside.

Have fun!

hale
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<MSG2>

Subject: NEW: How Do I Cut A Cat's-eye Chrysoberyl

I am considering making a high-dome cab on a high quality
piece of cat's-eye chrysoberyl. I have experience working
with other types of stones, and have studied the mineralogy
of this material. I would very much appreciate any advice
and assistance in orienting the stone such that the
cat's-eye is centered as perfectly as possible when
completed.

I look forward to helpful techniques, this is my first
question to the group.

Thank you for your consideration and assistance.

Ian Beaty, age 15.
<dave@telonics.com>
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<MSG3>

Subject: NEW: Criterion or Gemking Saw Blades


Has anyone seen or used Criterion or Gemking saw blades? The
prices are low, and that makes me skeptical. The Criterion
24" blade is $226, and the Gemking 24" is $383.I have been
advised not to go below .105 thickness on the bigger
saw blades.The Criterion blade is .075.

Can anyone recommend a good 24" saw blade that is not too
expensive?

Wolfmann64@aol.com

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<MSG4>

Subject: Re: Treating Bisbee Malachite-Azurite

> From your favorite hardware store, get your self one kit of
> 330 water clear epoxy, the two part system, and one pint of
> acetone (very flammable). Mix the three components in a
> glass jar, taking care to be sure dissolving is thorough.
> Place material in jar, for one week. Turn material over and
> allow to soak for another week. Remove from jar, and let set
> for one more week before attempting to cut.

> <<There are several types of materials which (work) well for
> such.<<edit>>You may need to repeat the
> process a couple of times to make a complete cure.

Hi all,

Does this method works on any soft stone? I'm not sure I
know exactly what Bisbee Malachite-Azurite is. I've been
lurking, reading and saving all the digest issues for when
I have time to do more lap work. That time is just about
here and I have a lot of rough to play with, although some
of it isn't the best material (its just pretty). I will use
the cabs in jewelry, so I'm looking for different ways to
harden or seal the softer material.

Also, can you tell me what and where the KRE web site
mentioned above is and how can I find the rest of the edited
message from in the last paragraph?.

Thanks for any help and info.

Nancy
Nancy B. Widmer
nbwidmer@c-com.net
-------------------------------------------------------------
(Ed.Note: Nancy, the KRE website url is something close to:
<http://members.aol.com/vybtl/fischerstone.htm>; it is the
Web page of Vince King, who wrote the comment you cited.hale)
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<MSG5>

Subject: NEW: Dopping Opals

Recently, there was an exchange on Rockhounds about dopping
for Opals. I have copied most of the messages and have
received permission to publish them here. And have added some
comments, which I denote by starting with 'Hale:'.If you have
any comments, please send them in to be added to this thread.

Hale: It all started with a note from Mel Albright:
----------------------------------
How do you dop pure opal for cabbing? I normally use dop wax
and wooden dops. But, that requires heating the stone which I
don't think should be done with opal. So I don't know what to
do? HHHEEEEELLLLPPP!

"Mel Albright" <mela@galstar.com>
----------------------------------
USING WAX AND GENERAL TECHNIQUES

Hale: Several types of responses were printed; I have
collected them and arranged them according to the
recommendations. The first category suggests using waxes and
gives tips for using them:
----------------------------------
I assume (bad idea) that you're dopping Australian opal.
Suggest you look into the lower temp waxes. Check with your
local supplier to see what's available.

FWIsW: Have done a bit of faceting and cabbing of Opal,
Virgin Valley, Australian, Mexican, and Oregon. The last one
mentioned was the only one that'd ever given problems due to
it's water content. This is not suggest all of this type of
gem will fail, just an example of a bad episode.

If you'd allow the stone to rest out of water for a couple of
months, it will allow you determine it's stability. Any sign
of crazing suggests potential failure, which means that at
any moment it could go. The last alternative would be to use
epoxy.


Vincent King
Vybtl@aol.com
----------------------------------
Mel,
Don't panic. gently warm the opal sloooowly, might try a
little facetors trick and paint thinned shellac on side to be
dopped. The real trick is cutting & polishing without cutting
out all of the color. To remove the stone put it and 3 ice
cubes in small glass with a little water. Wait a few minutes
and the stone should pop off.

Earl
"Earl English" <ewenglish@blueridge.net>
----------------------------------
CYANOACRYLATE or SUPER GLUE

Hale: Most responders suggested super glues; I have deleted
all but those which also give tips for how to use super glue:
----------------------------------
Crazy glue works well. However there are a few tricks.

1st, use one of the cheaper glues. I use "crazy glue" the
brand, the original formula. I've glued a washer onto the
bottom of the base so that I can keep the tube in the base
and cover it after each application.

2nd I use a dowel for a dop. It needs to be prepared,
however. I find the best prep is to flatten it out on a high
speed sanding disk because this burns the wood a little.
That keeps the glue from soaking in and requiring repeated
applications.

3rd When you're finished cutting and polishing, cut the dop
off with a jeweler's saw and then drop the opal in a covered
container of acetone to remove the glue. the one drawback to
crazy glue is that left on too long, ie days it can remove a
hole from the back of the opal.

"Derek Levin" <stoneage@vermontel.com>
----------------------------------
For what it's worth. I have had good results with this
procedure doping opal.

Use a flat well polished agate slab and use hot wax to make
up dops in the size you need. Freeze them off. You can hand
sand them to suit your need.

I use one small spot of super glue to fasten the opal. To
remove be sure the stone is cool. I hold them under cold tap
water and then place in cooler a few minutes, they should
release on returning to room temperature leaving only a small
residue of the super glue which is east to remove.

I have damaged opal from HEAT but never from cooling stone.

Thomas W White <agatehead-kc@worldnet.att.net>
----------------------------------
I usually use cyanoacrylate (Crazy Glue) & dissolve it off
with acetone overnight. The pieces of opal I work are
generally small, say the size of a pencil eraser & smaller. I
dop 'em onto flatheaded wood screws. Usually the heads of
these mass-produced screws are not as flat as I'd like 'em to
be to get good contact, so they should be just touched up
lightly with a file. I prefer slotheads because the slot
gives the acetone better access afterward. If you're dopping
large opals (lucky you!!) you might try filing crisscross
grooves into the screwhead, again for better acetone access.

Another thing I do (and I know this sounds heretical) to
loosen the crazy glue, notably in triplets, is to heat the
screwshank with a mini torch about 1 inch below the stone,
obviously taking care to direct the flame away from the
stone. The screw with the stone on should be clamped in a
vise or something, then while you're heating it keep pressing
against the bottom of the stone with a screwdriver or
something similar. The crazy glue will soften, and the stone
pop off, without too much heat getting into it. But I do that
mainly for triplets.

Cheers
Hans Durstling
Moncton, Canada
sinico@nbnet.nb.ca (H.Durstling)
----------------------------------
I use a thick form of super glue it works very well . Use a
wooden dowel and just cut it off when you are done and sand
the residue off the back of the opal.

Mike
Mijo730@aol.com
----------------------------------
WHITE (WATER SOLUBLE) GLUE

Hale: A third set of recommendations suggested using water
soluble glues, commonly called white glues (like Elmer's):
----------------------------------
I was taught to use Carpenters' Glue - a yellow stronger
version of white glue. Try the hardware store. You work with
several stones at a time, rotating them so they get a chance
to dry out between sessions. It works quite well.

Karen
Karen Lechner <Lechners@compuserve.com>
----------------------------------
I've used Elmer's glue to dop them to either sticks or
roofing nails. The glue is soluble in water but the lag time
is enough to get the opal shaped and polished. Remove from
dop stick by soaking in water.

Roger K. Pabian
Roger Pabian <rpabian@unlinfo.unl.edu>
----------------------------------
EPOXY

Hale: There was only one suggestion involving epoxy:
----------------------------------
I use 2-part epoxy mix with dry cream of wheat for faceting
opals. Should work for cabbing too!

Debra
DMNajera@aol.com
----------------------------------
Hale: Cream of wheat? I was so fascinated by this response
that I wrote to Debra and asked her to amplify on it, and
this is what she said:
----------------------------------
"This came from the October 1995 issue of Columbia-Willamette
Faceter's Guild newsletter - Facets. It was an article
writing about cold-dopping for faceting -- "Adhesives and
Techniques for Cold Dopping" by Charles Covill. ..(snip)...
Here's the info:
-------------------------------------------------------------
"Because the Epoxy goes through some pretty severe thermal
changes as well as contractions and expansion while it is
setting up, I have been experimenting with several different
additives to try to keep the shock to the gemstone at a
minimum and to keep the culet intact. Currently I am using
NABISCO INSTANT CREAM OF WHEAT with good results."

"With a clean piece of paper I lay down a bead of Epoxy and
hardener side by side, then sprinkle on my cream of wheat.
Just shake off all that doesn't stick to the beads into the
waste basket. Next stir the mixture with a flat blade so
that you move all of it. Using a pointed instrument (tooth
pick) will result in an incomplete bonding because it is not
mixed thoroughly and can cause the stone to shift."

"I've used a tooth pick to mix with no problems at all. You
could probably use a popsicle stick! To get the stone off,
soak in nail polisher remover. I soaked a topaz for 3 hours
last night and that was enough time to dissolve the epoxy
mix. Hope that helps!"
----------------------------------
Hale: I contacted Charles and asked him for a copy of the
paper, and permission to reprint it here. He agreed, and is
sending a copy.
----------------------------------
NEW GLUE

Hale: Another respondent said that he had been using a new
glue from the Permatex Corp called Quick-Gel. He said that
he sanded a nail head flat, and applied a small amount of the
glue. He adds the stone and then adds a small bead of glue
around the edges after it's set up a bit; then let alone for
10 minutes. Soaking in acetone for a couple of minutes will
release the stone.
----------------------------------
MEL'S RESPONSE:

Thanks all for the recommendations on dopping opal.

In summary, the consensus seems to be
1. use super glue (or elmer's glue with water removal)
2. It requires a hard, smooth surface on the dop - i.e.
burnished wood, smoothed nailhead, screw with slots (slots
for easier acetone penetration), etc.
3. acetone removes it without harming the opal
4. If you leave it on too long, it can cause damage to the
opal.


Mel Albright
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