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This list digest contains the following message subjects:

1. LapDigest News for Issue No. 76 - Thur 10/23/97
2. NEW: Feathering Glue
4. RE: Vertical Flat Lap Problems
5. RE: Vertical Flat Lap Problems
6. BIO: Comments on- Raymond Rodebaugh
7. FS: Moonstone Rough

Subject: LapDigest News for Issue No. 76 - Thur 10/23/97

Two more thread files are now in the Archives; they are:

I sent the thread on leaking lids to Lortone in hopes that
they can shed some light on why pressure or vacuum can occur
in a tumbling run, and how to alleviate these conditions.

Also a list of all of the information files in the Archives
has been put in a file named ListOfInfoFiles.txt, and is in
the Archives.

Received a letter from Jeremy Condliffe, who said that all
Compuserve members also have large files turned into files
which must be read by word processors. If this is happening
to you, please write and tell me so I can get some idea how
large this problem is.

The last word on putting quartz next to a computer is given
below. The LAST word!!! (grin)

It is turning colder day by day. We had 29 degrees this
morning. So the end of field trips is approaching and we can
think more and more about doing inside lapidary work. Think
SAFE at the same time, and above all, think FUN!!


Subject: NEW: Feathering Glue

-- Greetings All. To Russ and others who may be interested...
The proper name is actually that I have it in front of
me....Feathering Disc Adhesive NO.80416. The 150 ml tube I
have is black with yellow printing and is made by 3M. 3M is a
Canadian Company in London Ontario, N6A-4T1... but I'm sure
you can also buy it in your neck of the woods :)

It's main use is in autobody shops for attaching sanding
discs to orbital sanders. It's a glue that never hardens, but
holds papers and leather discs to wheels solidly. I have
never had a disc move on me since I started using this
adhesive 5 years ago. I highly recommend it. Just make sure
when you are done using your wet/dry paper or
peel it off the lap and store it. The glue still attached to
the paper and to your lap makes it neccessary to store them
grit down, but that's not a problem for me. Once applied to
your lap, it rarely has to be replenished, if it feels tacky
to the touch, it's still good...great stuff!

Dave Daigle, Edmonton, Alberta

The Edmonton Tumblewood Lapidary Club


I think what Russ is looking for is Feathering disc adhesive.
It is available at any automotive supply shop and is similar
to contact cement in that you should coat both the paper and
lap surface. I don't think it would work well to dop up your
opals with because it is a pain to try and remove it from
things. Have you tried double back tape? Woodworkers use it
to turn small objects so it must hold fairly well.


Non-commercial reprint use permitted

Subject: RE: Vertical Flat Lap Problems

When trying to preserve a glue joint on a dop, what I do when
facetting is to, after the glue is set, paint over with clear
fast drying nail polish. This is available for about a
dollar from any drugstore (there will also be $3.00 versions-
- bypass these).

Should work for cab laps also. The point of doing this in
facetting is to protect super glue dops from the water. So it
should work on the Waterglass also. Let me know if otherwise.

Fred Gillis

Non-commercial republish permission granted.

Subject: RE: Vertical Flat Lap Problems

<< First, I procured an IV drip system from one of our
veterinarians. This consists of a bag which holds maybe a
pint of water and a very narrow hose about 3 feet long.>>

Howdy !

When I purchased my first faceting machine (an old
Taylor) it had an I.V. bag drip system. I found the bag too
small and difficult to refill so, borrowing on some
experience raising tropical fish,I cut the bottom off a 2
liter coke bottle(even leaving a couple of 'tabs' through
which I melted holes with a soldering iron for hanging) then
drilled a hole in the cap through which I ran the I.V.
tubing, caulked in place and VIOLA! (voila' ;-) ) a nice
drip tank.

1 Lucky Texan

Subject: Comments on BIO: Raymond Rodebaugh

Dianne Karg wrote:

<<I was told by my network administrator that putting quartz
near your computer is an absolute no-no! Apparently the
vibrations of the quartz (even ones as small as in quartz
analog watches) can cause distortions on your hard drive.
Has anyone else heard of this? >>

Some network administrator is either pulling, very hard, on
someone elses leg, or has so little understanding of
electronics that one wonders how he/she ever became a network
admin. Quartz does not have vibrations. Period. Thats true
for all crystals or materials at rest. What quartz DOES
have, in common with a number of other materials, is a
property called piezoelectricity. This means that when you
apply a voltage across a quartz crystal, it will expand or
contract, just a hair. Applying pressure to the crystal, the
reverse of the above, generates a voltage. Quartz is
normally a very good insulator, and does not pass an electric
current. But just like a bell has a resonant frequency (it's
tone), each quartz crystal also has such a resonant
frequency, at which, when struck, it will tend to vibrate
(just like a bell) If an alternating current is applied to
the crystal which is at this frequency, then because of the
interaction between the voltage and the fact that this
voltage can cause the crystal to physically contract or
expand, and in reverse, that same contraction and expansion
can cause a voltage to be generated, then although the quartz
crystal is still an insulator, an alternating frequency at
exactly the right frequency, can pass through the crystal.
Nothing is being "emanated" or "radiated" by the crystal.
All it is is a filter, which can be made to only allow a very
precise frequency of an alternating current to go through it,
while any other frequencies are blocked. To the other
frequencies, the quartz crystal is like a cut, open wire. No
circuit. To the right precise frequency, it's a conducting
wire. When the crystal is ground to just the right size to
be resonant in this way at some desired frequency, and is
then placed in a circuit that is trying to generate an
alternating current, the crystal can be used to control
exactly what frequency the current alternates at, since only
that one exact frequency can pass through it. Again, I'd
stress that this is a passive role, and only in an electronic
circuit. A single quartz crystal sitting on a shelf is doing
exactly nothing. If you hit it hard in certain directions,
you'll generate a very short high voltage static pulse, but I
doubt that this is so dangerous, unless you're in the habit
of hammering your quartz crystals while holding them in
electrical contact with your computer. Quite a number of
other materials, including notably tourmaline, and even some
plastics, will do the same thing... The most common place
most of us will have seen this effect is when grinding
quartz. In some cases, when ground dry, you'll see bright
flashes of light coming from the quarz as its ground. This
is actually a slightly different property, but it's closely

But perhaps your net admin instead had meant to say, Don't
bring any magnets near your hard drive. If he'd said that,
then he would have been very correct. Hard drives, and discs,
and tapes, all use magnetic recording techniques, and even a
little refrigerator type magnet, carelessly placed on a
diskette, can destroy it. A hard drive is a bit better
shielded, and is inside your machine, but still, it's
vulnerable if you bring strong magnetic fields near it. One
possible mistake here can be using the wrong type of speakers
on your audio card. Those made for computers should be
magnetically shielded. But some other types are not, and if
placed near disks or a computer, the magnetic field from the
speakers can cause damamge. The same can be said of many
types of electric motors, which all operate with magnetic
fields. If the motor isn't properly shielded magnetically,
then the motor's field can damamge data... Think "desk fans"
and "electric pencil sharpeners" and the like, here...

And now, I think, perhaps it's time to get back away from the
voodoo crystal vibrations myths and instead, go back to nice
friendly lapidary subjects...

Peter Rowe
(Ed. Note: OK, gang, that is the last and the authoratative
word on effects of putting quartz crystals next to your
computer. So go to Mt. Ida, collect large clusters, put them
where you wish, but NO MORE letters, please!!! As Peter (who
you can see is taciturn to a fault!) says, lets get back to
lapidary! (smile) .. hale)

Subject: FS Moonstone Rough

Moonstone assorted colors... good cabbing rough
Have about 20 pounds... $10.00 per pound plus shipping
Best wishes

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