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. 116 - Friday 2/19/98
2. NEW: Expanding Drum Question
3. NEW: Expanding Drum Question
4. RE: Electroforming (Metal Plating) On Lapidary
5. RE: Electroforming (Metal Plating) On Lapidary
6. RE: Treating Bisbee Malachite-Azurite
7. RE: Treating Bisbee Malachite-Azurite
8. RE: Saw Oil and PCBs
9. RE: Saw Oil and PCBs
10. BIO: Paul Maloney
11. BIO: Kathrine Waters
12. FS: Supreme Gem Tech Unit


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<MSG1>

Subject: LapDigest News for Issue No. 116 - Friday 2/19/98

It is nice getting accolades. And we have received two of
them concerning the paper on plating. Lloyd Duncan wrote:

"A big THANK YOU to George Butts for taking the time to share
his knowledge with us. What a great job! Many questions
answered and required technical information presented in a
way we could all understand. I have watched for
'electroplating non-conductive surfaces information' for over
a year, and this is the most understandable treatise I have
seen on the topic."

And Vince King wrote:

"Wow!

George's paper is definitely one for the record books.
Thanks to you both, Hale and George for sharing this
knowledge! The pot bellied web glows bright tonight!"

Thanks, guys. I also thought George did a great job!. And I
was proud to include it.

The weather is changing... We have had almost a week of
beautiful spring-like temperatures and sunshine. I awoke
this morning to the sound of a mockingbirg singing. It's time
to come alive again and get out and LIVE!! Do it!! ..and
have fun!!

hale
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<MSG2>

Subject: NEW: Expanding Drum Question


I just completed constructing my Cabmate unit. I took great
care to ensure that the machine was quiet and as vibration
free as possible. I installed a 2 HP 100 volt DC motor with
infinite variable speed and feed back load sensing. It runs
great. I installed a new expanding drum to use with various
grit belts. The Drum vibrates like crazy, it is ~ 1/8" out of
round.

My question: is this normal for these expanding drums? It is
installed correctly & tight with the bushing etc. Or do I
have a defective drum, perhaps mismolded?

Chuck
ChuckSmy@aol.com
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<MSG3>

Subject: NEW: Expanding Drum Question


Possible reasons for vibration:
1. If you try to run the drum without a belt, it will do
crazy things. I don't for a minute suppose you are doing
this, but had to list it.

2. Perhaps you have mounted the drum back to front. The
slots through the drum should point away from you at the top
and towards you at the bottom.

3. Try rotating the belt about a quarter of a turn,
relative to the drum and make sure it is straight.

If this doesn't fix it, I suppose you must have a
defective drum and the supplier should replace it.

Good luck!

Goeff Haughton
<ghaughto@med.unc.edu>
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<MSG4>

Subject: RE: Electroforming (Metal Plating) On Lapidary

I was asked to expand on my saying not to use a variable
transformer having a common input/output line. My answer:

First of all, if you construct your own current regulator
and/or power supply, it is critical that you understand the
electrical principles involved. I HIGHLY RECOMMEND that
you include a "GFI" (Ground Fault Interrupter) in your
circuit. A GFI senses the equality of normal current in the
"hot" line compared to the current returned in the "neutral"
line. If there is an imbalance, it "assumes" a leak to
ground and cuts the electricity fast enough to protect a
person from accidental shock. If it weren't for the fact
that one side of our 117v AC supply mains is grounded, we
wouldn't care. As it is, full line voltage is presented by
the "hot" side to a "ground" like a water or gas pipe, a
conduit, damp concrete floor, etc.

My comment about a variable transformer should have been
clarified to say "do not use a variable transformer UNLESS
it feeds an isolating transformer". My concern is that if
someone builds their own system, it's real easy to use a
variac to get variable voltage without realizing that one
side of an auto-transformer connects directly with the
117AC. Worse, is the fact that a raw Variac, wound up too
high, will output lethal voltage in itself.

The purpose of an isolation transformer is to prevent any
electrical connection between the input supply lines and the
output use lines. The input-output energy coupled between
the primary winding and secondary windings is only by
magnetism.

Any transformer with two PHYSICALLY UNCONNECTED windings
will isolate the output from input relative to ground. A
standard step-down transformer is understood to be
"isolating" but not referred to as such since that's not
it's primary purpose.

An auto-transformer (viz, "VARIAC") is a three-wire device
where one side of the input line is also one side of the
output, connected commonly to the ends of BOTH the primary
and secondary. That is, an auto-transformer has three
terminals and one side of the output is, in effect, plugged
directly into the household socket.

Electrocution is by a flow of electrons (current) through
the body being "pushed" by the electrical force (voltage).
By keeping the voltage below that which will overcome body
resistance (at least under 50v and preferably below 30v) and
by isolating the plating leads from the household lines,
that source of hazard is eliminated.

Using an auto-transformer to feed a step-down transformer is
accepted practice for a plating variable power supply. The
auto-transformer provides variable voltage input and the
step-down transformer both isolates and sets a non-lethal
cap on the output voltage. Such a system, operating at
below harmful voltage and being electrically isolated from
the household mains, is basically safe from electrical
shock.


George Butts
<gtbutts@infinet.com>

(non-commercial republish permission granted)
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<MSG5>

Subject: RE: Electroforming (Metal Plating) On Lapidary


I have a little experience in semiconductor plating and this
is a guess.

The "brighteners" are organic ionic compounds. They are
added to electroplating baths in minute amounts to
counteract Coulombs Law. This is where the electric field
on a charged object is much stronger at sharp bends in the
surface. This is how lightning rods work. The sharp tip
builds up a strong enough field that the electricity bleeds
off before there is enough for a lightning strike.

The "brighteners" are drawn to the sharp areas and block
some of the flow of metal ions to there so that a more
uniform coat is achieved. This drawing to rough surfaces is
part of the reason preparing a smooth surface is so
important.

The organics used for this purpose in semiconductors have a
short life in the plating bath and are metered in carefully
during processing.

bobg@in-tch.com

"non-commercial republish permission granted"
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<MSG6>

Subject: RE: Treating Bisbee Malachite-Azurite

<<There is a gentleman named Jonathan(?) Starr, somewhere in
Arizona, who can stabilize anything.....>>


I'd be extremely cautious in sending anything off to Jonathan
Starr for stabilizing. I sent them some really nice fossil
ivory some time back, and it came back thoroughly
contaminated with the blue dye used for "enhancing" turquoise.
It also reeked of polyester resin, not my favorite perfume.
But if you want to turn stone into stinky blue plastic simply
by adding money, this might be the way to go...

Andrew Werby - United Artworks
drewid@lanminds.com
Sculpture, Jewelry, and Other Art Stuff
http://users.lanminds.com/~drewid
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<MSG7>

Subject: RE: Treating Bisbee Malachite-Azurite


<<He uses resins and first vacuum then pressure to drive the
material into the porosities in the rock.>>

There are several types of materials which (work) well for
such. Try "Wilco 55" for one -- it's a thin varnish compound
available through hardware stores. Another is sold by
"Z-Brick". For sealing the finished work, the sealant needs
to be thin and these work very well for the purpose and will
absorb into the mineral easily. You may need to repeat the
process a couple of times to make a complete cure.

Gil Shea
legal@mtaonline.net
non-commercial republish permission granted
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<MSG8>

Subject: RE: Saw Oil and PCBs

In following the discussion about cleaning the oil in
rock saws I might have a helpful solution.

OIL AND WATER DON'T MIX! (usually)

If you dumped your dirty oil in a plastic bucket 1/3 full
of water and let it sit, the oil being lighter than water,
would float on top of the water.

The sludge, rock chips, dirt, etc. should settle out of the
oil and sink through the oil and in to the bottom layer of
water. You can then pour off, decant, or siphon the clean
oil off the top of the water. All your sludge should be
laying on the bottom of the bucket.

I've used this same technique for a parts washer which has
cleaning solvent floating on top of water. I have used it
for 20 years to clean engine parts and bearings on our farm.
I have a submersible pump mounted in the layer of solvent
and it works great. Of course after a while you have to
empty everything out and dump the mud and sludge at the
bottom of the container.

Hope this helps.

Al
akalin@satcom.net
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<MSG9>

Subject: RE: Saw Oil and PCBs


<<Transformer Oil: NO, NO, a thousand times no!>>

I'm not real sure on this point, but I have constantly been
told that Transformer Oils generate PCBs through use also,
and that as such the "Used Oils" were the major problem,

<<They didn't do you any favors giving you that stuff>>

Especially Hazardous Waste, you could wind up in legal
hassles you don't want believe me. Once you're in possession
of it, you're liable for it, and for the proper disposal of
it, "Forever" under the law

Gil Shea
legal@mtaonline.net

non-commercial republish permission granted
-------------------------------------------------------------
(Ed. Note: There have been many statements made about PCBs
and I thought it was necessary to try to track down some data
about them and about their presence now in transformer and
other electrical equipment oils. I consulted four sources: a
former transformer design engineer, the internet, and two
engineers in power companies directly concerned with topics
like this. This is what I found:

1. Transformers without PCBs initially do not generate PCBs
through usage.

2. In a large power company, with several thousand
transformers in use, there may be a very few still in service
which have not been swapped out since the 1970s and which
could contain PCBs. As these fail they are brought back and
tested for PCBs and if PCBs are present, the oil is sent to a
licensed disposal facility. Otherwise, the used oil may be
sold. There is almost no chance that you could buy used
transformer oil from a power utility with PCBs in it today.

3. I do not know any of the characteristics of "transformer"
oils, and am sure that there are many different kinds of
transformer oils available. I do not know whether any of
them are good or bad for use in rock saws.

What are the physical characteristics of a good saw oil?
Bill Ritter, who was head of Contempo Lapidary, wrote a
paper entitled "My Saw Won't Cut", first published in
Eclectic Lapidary and republished in Issue 37 of LapDigest,
in which he stated: "We define the proper oil as one that
has a high flash point (remember that diesel and kerosene
are FUELS!), has no carcinogens, has a very low viscosity
(almost like water or a 3-in-1 oil), and has a low odor." I
am trying to collect these data on Pella, Almag, and several
others, including transformer oils, and RV antifreeze and
will present those data when they become available. They
should help answer the question about the acceptability of
various oils...hale)
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<MSG10>

Subject: BIO: Paul Maloney


Hi All;

I have been interested in Lapidary and have sold, cut and
been involved in the hobby for about 20 years. I have been
unable to do much cutting/collecting for the past 5 or 6
years because of other commitments, kids, work etc. but I am
trying to get going again. I have old Raytech equipment and
a Graves facetor as well as a 10" and 6" saws. I most enjoy
cutting opal and picture jasper.

For the past three years I have been editor/publisher of "The
Pick & Wheel", a small publication for the Westchester
Mineral & Gem Society in Eastchester, NY. Gives me another
excuse for having the expensive computer and printer
equipment.

Looking forward to reading and contributing when I can to the
Digest.

Paul Maloney
pemaloney1@aol.com
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Subject: BIO: Kathrine Waters

Hello Hale,
My name is Kathrine Waters from Ishpeming, MIchigan. I
am a member of the Ishpeming Rock & Mineral club and the
secretary. I'm just getting started in the learning process
of rocks and minerals, and an interest in carving.

I have a Foredom Series CC portable grinder. I have worked on
some talc that we have here locally. Also I bought some pink
alabaster from our annual rock show. I own an art studio,
selling my paintings, clay beads and art supply retail. I
would like to carve rock also and hope the Lapidary Digest
will be interesting and informative.
Thanks,

Kathy
<bwaters@nmu.edu>
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<MSG12>

Subject: FS: Supreme Gem Tech Unit


For Sale: Supreme Gem Tech Unit. Six wheels for grinding and
finishing plus leather buffer on end. Wheels are diamond.
Purchased in 1985 for $850.00 This unit resembles a "Pixie"
unit made by Diamond Pacific and will easily set on a kitchen
table.

Will UPS unit anywhere in USA for $450.00
More info call: 309-799-5734 9 AM to 8 PM CST.

Posted by:

Floyd Dopler, President Black Hawk Gem & Mineral Club
Rock Island, Illinois E mail: Fdopler@aol.com
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