On Feb 4, 12:47*am, Keith P Walsh <keith.p.wa...[at]btinternet.com>
wrote:
- quote -

It was not dereacted or dedissolved.

- quote -

a composite

- quote -

More unhappy than, say, piezoelèctric chewing effects within the CEJ?

-Aut

On Feb 3, 1:50 am, Keith P Walsh <keith.p.wa...[at]btinternet.com> wrote:
- quote -

whether or not = whether or not whether

- quote -

Is human tissva a superconductor--in the relevant band? That is, not
in the picovolts-microvolts of the nuclear radio and aqveose ionic
background, but in the millivolts of lone metals, which the human body
is not?

- quote -

Yes. And reception doesn't happen either.

- quote -

That's a cretinose argument for thome who can't add. If there's a
damping mekanism for stronger signals, the output still must show up
somewhere.

- quote -

A static magnetic field is itself born of elèctric currend, and would
need to feed another body to make another, and no longer stay static.

- quote -

Which I like to call IC (AC + DC), intermittent currend, with one sign
and on one side of the baseline.

[snip]

- quote -

It was pap.

[snip]

-AutOn Feb 3, 1:50 am, Keith P Walsh <keith.p.wa...[at]btinternet.com>
wrote:
- quote -

whether or not = whether or not whether

- quote -

Is human tissva a superconductor--in the relevant band? That is, not
in the picovolts-microvolts of the nuclear radio and aqveose ionic
background, but in the millivolts of lone metals, which the human body
is not?

- quote -

Yes. And reception doesn't happen either.

- quote -

That's a cretinose argument for thome who can't add. If there's a
damping mekanism for stronger signals, the output still must show up
somewhere.

- quote -

A static magnetic field is itself born of elèctric currend, and would
need to feed another body to make another, and no longer stay static.

- quote -

Which I like to call IC (AC + DC), intermittent currend, with one sign
and on one side of the baseline.

[snip]

- quote -

It was pap.

[snip]

-Aut

On 7 Feb, 15:06, Mark & Steven Bornfeld <bornfeldm...[at]dentaltwins.com>
wrote:

- quote -

Like I said, it's a common misconception.

Keith P Walsh wrote:
- quote -


Take it up with Webster:

http://www.merriam-webster.com/dictionary/amalgam


- quote -


--
Mark & Steven Bornfeld DDS
http://www.dentaltwins.com
Brooklyn, NY
718-258-5001

On 6 Feb, 14:27, Steven Bornfeld <dentaltwinm...[at]earthlink.net> wrote:

- quote -

How about mercury amalgams?

Do you use them?

(And remember, it's NOT a pleonasm.)

Keith P Walsh

Keith P Walsh wrote:
- quote -


(snip--sorry).

I'm sure it's possible. I've watched for years as the denizens of
sci.materials and perhaps sci.physics have encouraged you to conduct
your tests.
You can try it with plutonium, for all I care. I'm not using gallium,
and I'm neither a physicist nor a metallurgist. And I'm not going to
use gallium "alloys" in my practice.
You should know though that I'm the type of guy who tests 9-volt
batteries by touching them to my tongue. Maybe that's my problem right
there.

Steve

On 5 Feb, 16:13, Paul O <first.d.l...[at]company.com> wrote:
- quote -

You're beginning to sound desperate Paul.

The reason why I keep returning to these newsgroups with the same old
questions is because those questions have never been answered.

I recognise that people like you and Jim Pennino are able to convince
yourselves that you have answered my questions, but you are mistaken.
All you ever do is simply make up excuses for ignoring them because
you don't know what the answers are.

Olin Perry Norton even appeared to have convinced himself that he had
conclusively dealt with my questions by asking me one of his own which
I couldn't answer!

How obtuse is that!?

Some of the earliest questions I posted to sci.med.dentistry were
concerned with the physical properties of dental amalgams, and why it
appears that properties such as their electrical conductivity and
magnetic susceptibility had ever been measured. And those questions
are still not resolved today.

I still bother to check. (I doubt very much whether any of you guys
ever do.) And on a recent search I found a paper with the following
title:

"Magnetic susceptibility and electrical conductivity of metallic
dental materials and their impact on MR imaging artifacts"

- the summary of which can be seen at:

http://www.demajournal.com/article/S...199-6/abstract

I was sufficiently interested to pay the online fee to buy the
complete article (see, I'm not such a cheapskate after all!), and do
you know what I discovered? I discovered that the "amalgams" which the
paper claims to have tested were not amalgams at all. They were simply
samples of the various ALLOYS which are supplied to dentists for
mixing with liquid mercury to form amalgams.

As it happens, two of those alloys do have some mercury in them -
Starfill NG2 (3% Hg) and Ana 2000 Duet (2% Hg). However, despite their
mercury content, these materials are NOT amalgams. They are ALLOYS.
Dentists will appreciate perfectly well that you can't make amalgams
with those proportions of mercury. These materials would have been
formed by mixing ALL of the constituents (Ag 70%, CU 15%, Hg 3%, Sn
12%; and; Ag 43%, Cu 25.4%, Hg 2%, Sn 29.6%, respectively) in their
molten states, i.e. at a temperature well above room temperature, and
then allowed to cool at controlled rate.

The other "amalgams" tested, i.e. those with 0% mercury content, were
not amalgams either, they too were ALLOYS (Safargam Plus, Safargam
NG2, Safargam Special and Ana 70 Duett).

These alloys are purposely formulated for use in amalgams. It may make
sense therefore to refer to them by the term "amalgam alloys", in
which term the word "amalgam" serves as an adjective.

But they are NOT amalgams. And in the physical world, regardless of
what anyone calls them, they do not accurately represent the physical
composition of any material that would be found in anyone's mouth in
the form of an amalgam dental filling.

The discovery of this paper therefore does not answer any of my
questions regarding the physical properties of amalgam fillings.

On the contrary, it raises more questions.

Such as, if someone can get a Phd measuring the electrical and
electromagnetic properties of the alloys used for mixing amalgams, why
hasn't anyone bohered to do the same with samples of actual amalgams
(i.e. after the alloys have been turned into powder and mixed with
liquid mercury to form the actual amalgams which are placed in peopl's
teeth.)?

The same paper also presents the results of measurements for a range
of other metal alloys, those used for crowns, bridges, braces, etc,.

So we have the properties of electrical conductivity and magnetic
susceptibility for just about every type of metallic material that
dentists place in people's mouths, and for the ALLOYS used for mixing
amalgams, but NOT for the mixed amalgams themselves.

And with regard to the actual amalgams themselves, i.e. as they appear
in people's teeth, we are still ignorant.

How do you explain that?

And don't tell me that it's up to me to do the measurements myself.

That's just the same old excuse that you always use simply to avoid
the question.

Keith P Walsh

On 4 Feb, 16:41, Mark & Steven Bornfeld <bornfeldm...[at]dentaltwins.com>
wrote:

- quote -

It has been demonstrated on planet earth that (mercury) amalgam dental
fillings generate electrical potentials with magnitudes of up to 350
millivolts. See:

http://book.boot.users.btopenworld.com/dutch.htm

It has also been demonstrated that these potentials can be detected
even when the amalgams are not in contact with any saliva in the
mouth. See:

http://jdr.sagepub.com/cgi/reprint/31/2/205

And another research study carried out in Poland (which I believe is
also on planet earth) has even demonstrated experimentally that the
electrical potentials generated by amalgam fillings are quickly
regenerated after being discharged. See:

http://www.ncbi.nlm.nih.gov/pubmed/2...?dopt=Abstract

Do you think that it should be possible to carry out (on planet earth
of course) research studies to compare the electrical behavior of
amalgams made with liquid gallium (gallium amalgams) with that of
mercury amalgams?

Keith P Walsh

Keith P Walsh wrote, On 2/5/2009 5:02 AM:
- quote -

Stop being such a cheapskate! If you really felt strongly about the
health of children you wouldn't let a few measly dollars stand in the
way of this important research. Now take a crowbar, open up your wallet,
an get that DVM.

Besides, you don't need to purchase a DVM they are readily available for
lease at any test equipment rental store. See:
<http://www.testequipmenthq.com/>
<http://www.livingston.co.uk/>
<http://www.etestdirect.com/>
Do a web search, you will be able to find dozens more.

Another way to go is to purchase a used DVM. You will not need the
latest and greatest equipment for your experiment. Just a good, reliable
meter that can measure in the microvolt range.

Good luck. We are all waiting to hear about your results.

--

Paul D Oosterhout
I work for SAIC (but I don't speak for SAIC)

On 4 Feb, 15:44, Paul O <first.d.l...[at]company.com> wrote:

- quote -

The measurements which can be made with a good digital voltmeter have
already been demonstrated, see,

http://book.boot.users.btopenworld.com/potentials.htm

(These were taken by Dr Jack Levenson, hero of the mercury-free
dentistry movement in the UK, but sadly now deceased.)

The potentials measured here showed up even though the fillings were
not in contact with any saliva - which shouldn't be surprising since
it was first demonstrated that this is the case way back in 1952, see:

http://jdr.sagepub.com/cgi/reprint/31/2/205

Experimental procedures to confirm whether or not these electrical
potentials do in fact excite neurological synapses in the vicinity of
dental fillings would have to positively detect the occurrence, or the
lack of occurrence, of such excitation in the nerve fibers.

I believe that instruments do exist which are sensitive enough to be
able do this. But a "good" digital voltmeter costing less than $100 is
not one of them.

I'm sure I've explained all this to you before. (Perhaps it's you who
is habitually failing to retain the significant parts of the argument
here.)

Keith P Walsh

Keith P Walsh wrote:
- quote -


Sorry Keith. I'm not interested in the semantics of what your
definition of amalgam vs. alloy is. I'm a clinical dentist, and I want
my materials to work on planet earth.

Carry on,
Steve

--
Mark & Steven Bornfeld DDS
http://www.dentaltwins.com
Brooklyn, NY
718-258-5001

Keith P Walsh wrote, On 2/4/2009 3:47 AM:
- quote -

Your knowlege of the electrical behavior of mixtures of metal is purely
speculative. You have never attempted to make even the most basic
measurements to back up your claims. Purchase some amalgam materials,
fabricate some test samples, assemble a test fixture, rent (or borrow) a
good digital volt meter and take some measurements. Then you will KNOW
the thermal electrical behavior of dental amalgams.

- quote -

Do your own work, publish your results, and then bask in praise that
will befall unto you.

Best of luck,

--

Paul D Oosterhout
I work for SAIC (but I don't speak for SAIC)

On 3 Feb, 14:33, Mark & Steven Bornfeld <bornfeldm...[at]dentaltwins.com>
wrote:

- quote -

Dear Steve,

I think that the main reason why the term "gallium amalgam" might be
misinterpreted is because of the widespread misconception that, by
definition, an "amalgam" must have mercury in it.

This also explains why the the types of gallium amalgams that we are
talking about here, which do not have any mercury in them, are
sometimes erroneously referred to as "gallium alloys", e.g.:

http://www.cda-adc.ca/jcda/vol-64/issue-9/645.html

Of course, it may be argued that, whilst establishing a consistent
nomenclature is important in any scientific discipline (including that
of dental materials science), the names that we actually give to
physical entities is perhaps of secondary importance to the correct
identification of their physical properties and behaviors.

However, I do think that in this instance it might be helpful, as well
as perfectly correct, for us to establish that the true origin of the
word "amalgam", as applied to certain types of mixtures of metals, is
NOT dependent upon there being mercury included in the mix, but is in
fact defined by the general process by which they are formed; i.e.
that of mixing a quantity of a liquid metal "amalgamating agent"
together with solid particles of another metal at a temperature which
is below the melting point of the solid metal, and then allowing the
mixture to harden by a process which might reasonably be termed
"amalgamation".

The metallic element gallium melts at around 30 degrees celsius. It
can therefore be used in amalgamation processes such as this to form
amalgams by mixing it together with bits of solid metals or alloys at
a temperature slightly above that of room temperature (say, below 40
degrees celsius). The type of material that you get from such a
process could not be accurately described as an alloy (or what I
sometimes call a "true alloy) because a significant part of its volume
would remain as the "unreacted", or "undissolved" cores of the
original grains of solid alloy used in the mix, and these would not
have any gallium in them at all.

So it wouldn't be "an alloy". It would be "bits of an alloy all held
together in a matrix of a dissimilar metallic composition formed by
the liquid gallium in dissolving the outer layers only of the original
solid particles". Or, more generally, an inhomogeneous mixture of
dissimilar mixtures of metals.

It is from the requirement to distinguish materials of this type that
the term "amalgam" originates.

Primarily such materials are distinguished in the physical sense by
their much greater degree of material inhomogeneity, as compared with
that of true alloys, and this distinction comes from the complementary
fact that true alloys have a much greater degree of material
homogeneity due to their being formed by mixing together the
constituent metals at a sufficiently high temperature such that they
are ALL in the liquid state.

By this definition, therefore, a gallium amalgam may be considered no
more a true alloy than a mercury amalgam is.

I am already aware that attempts are been made to formulate suitable
gallium amalgams for use as restorative dental materials.

However, as far as I can tell the principal motivation for this is to
find a viable alternative to the use of mercury amalgams.

And, again to the best of my knowledge, the reason for this is concern
for the possible toxic effects that the mercury in mercury amalgams
may have on the human body.

Since I know that you have read, and often responded to, many of my
enquiries to sci.med.dentistry over the years, I presume that you will
be aware that my own particular interest in this topic is not the
toxic properties of mercury, but rather the electrical behavior of
amalgams. And in fact my interest in the subject dates back to the
early 1990s, beginning with a series of letters which I wrote towards
the end of 1992 enquiring about the electrical properties of dental
amalgams. You can read them at:


http://book.boot.users.btopenworld.com/intro.htm


As a result of the response to these letters, and of my own personal
experiences both before and after they were written, I have come to
believe that the electrical potentials generated by metal amalgam
dental fillings are able to dissipate electrical energy through the
nerves in people's heads and, in so doing, make them unhappy.

And in extreme though not unusual cases they are also able to cause
permanent neurological injury which cannot be repaired simply by the
removal of the fillings.

Scientific evidence for the existence of amalgam potentials is well
documented.

And from my knowledge of the electrical behavior of mixtures of
metals, I have no reason to expect that the electrical potentials
generated by dental restorations constructed using gallium amalgams,
rather than mercury amalgams, will be any less significant in
magnitude.

I remember reading a comment some years ago that if dental (mercury)
amalgams were being invented right now their use would never be
approved by the US Food and Drug Administration (the implication being
that the implied approval that their use has now is only due to the
application of the somewhat unscientific principle that "we've been
using them for so long that there can't possibly be anything wrong
with them!").

My hope on the advent of gallium amalgams is that someone, perhaps the
FDA, or the ADA, or an erudite young scientist in a university
materials science lab somewhere, will recognise that the interaction
of the electrical (not only galvanic, but also thermoelectric and
electromagnetic) behaviors of these new materials with the human body
ought to be investigated thoroughly first before they can be approved
for this use. Something which has still never been done with mercury
amalgams.

Keith P Walsh

Keith P Walsh wrote:
- quote -


I will accept your use of the term "gallium amalgam" though it is
seldom used and hence can be misinterpreted.
In fact, dental restoratives have been made using gallium as a major
component; unfortunately their performance has been disappointing:

http://www.cda-adc.ca/jcda/vol-64/issue-9/645.html

Steve

--
Mark & Steven Bornfeld DDS
http://www.dentaltwins.com
Brooklyn, NY
718-258-5001

On 2 Feb, 21:12, Olin Perry Norton <mylastn...[at]icet.msstate.invalid>
wrote:

Mr Norton.

Thank you for your contribution.

In reply, first of all, can I take it that you agree with my
description of the difference between an amalgam and an alloy (which
is not dependent upon whether or not the thermoelectric eddy currents
generated by the amalgams are detectable by human neurological
tissue.)? And also, for the benefit of my friend alchazz, that
amalgams may be formed using liquid gallium as the amalgamating agent
rather than liquid mercury, with the consequence that there is no
mercury in the resulting gallium amalgams?


- quote -


OK then, I'll address it now.

There is a basic inconsistency in the argument that you have presented
here (OK I know, you've really only presented a question).

The inconsistency which you imply in your question is that, although
the SQUID detector is sensitive enough to detect a very weak local
electromagnetic effect in the presence of the Earth's magnetic field,
which may be considered much stronger, human neurological tissue is
not sensitive enough to do the same.

I do not believe that you actually know whether or not this apparent
implication is correct. At least, I do not believe that you are able
to provide any direct scientific (i.e. experimental) evidence in
support of any such assertion.

And there in lies the rub. It appears that, in this "science obsessed"
world of ours, no-one has ever bothered to even try to find out (by
experiment) whether or not human neurological tissue is capable of
detecting the electromagnetic disturbances generated by the lumps of
inhomogeneous mixtures of metals that dentists routinely place in
children's teeth.

So a word of warning, if you want to set yourself up as some sort of
expert on the electromagnetic behavior of amalgam dental fillings, you
might first wish to consider why there doesn't appear to be anyone in
that role ahead of you (just think, with a little work you could be a
hero! And I'm sure that the American Dental Association would be most
generous in its gratitude for your expertise - but perhaps only if you
are able to tell them what they want to hear.)

My answer to your question is this. Perhaps human neurological tissue
detects weak local electromagnetic disturbances, even in the presence
of much stronger magnetic fields, in a similar way to that in which
the SQUID detector does. In the absence of any experimantal evidence
to the contrary why shouldn't it? Perhaps that's a question which you
might like to address (although I understand perfectly well that in
the absence of any relevant experimental evidence at all you'd only be
able to guess your answer anyway).

Electric, magnetic and electromagnetic fields are all manifestations
of the fundamental energy that makes up the Universe. They are not
characterised by field strength alone. Their nature is much more
complex than that. In the modern technique of nuclear resonance
imaging, the strength of the signal is largely irrelevant with regard
to the degree by which it is attenuated by the target. It's the
frquency/wavelength of the signal that matters most crucially, and if
it doesn't match the resonant frequency/wavelength of the target then
the attenuation doesn't happen, no matter how strong the signal is.

That's just an example to establish the principle that in certain
circumstances a weak signal may have a significant effect, whereas a
much stronger signal which has different characteristics might have no
effect at all in otherwise identical circumstances (a principle which
I believe that "Androcles" may have been alluding to in his response
to your contribution - thank's for the prompt Androcles).

If you would prefer to believe that there isn't any analogous
principle which might apply in our topic of interest well fine, go
ahead, but as I say, in the absence of any authoritative scientific
evidence on the matter, you're still only guessing.

There was another thread concerning this subject which I left
uncompleted a few years ago. I'd asked how one would know that the
process by which the local electromagnetic field generated by
thermoelectric eddy currents is not reversible, and I was presented
with the answer, "Elementry (sic) physics" - I'll just go and find it
(isn't Google Groups wonderful. In centuries to come they'll look back
on these arguments and laugh - or cry.)

Found it. Jim Pennino, 24 October 2006, in thread, "Electromagnetic
Effects in Inhomogeneous Materials", the relevant part of which went
like this:

++++++++++++++++++++++++++++++++++++++++++++++++++ +++++++++++++++++++++
+
- quote -


A static magnetic field will not generate a current.


- quote -


Elementry physics.
++++++++++++++++++++++++++++++++++++++++++++++++++ +++++++++++++++++++++
++


I'll start this one back up again now as well.

I agree that the influence of a static magnetic field is not able to
drive an electric current in a homogeneous electrical conductor. That
much is "elementary physics". However, having said that, at the moment
of establishing the new local magnetic field in the vicinity of the
conductor the charge carriers (electrons) in the conductor will be
disturbed momentarily, and may adopt a new static arrangement in order
to maintain equilibrium with the newly established local field,
although no further movement of the electrons will take place once
this static equilibrium condition is reached.

This situation is analogous to the effect of the application of a
temperature differential to a homogeneos electrical conductor, in that
on the establishment of the temperature differential the charge
carriers in it must adjust their position (thereby creating a
momentary "current" - i.e. displacement of charge) in order to
maintain equilibrium with the new temperature gradient. And that on
reaching the new equilibrium position, no further displacement of of
charge (current) can be induced or maintained by the static
temperature differential.

However, where inhomogeneous conductors are involved, such as a
circuit comprising elements of, say, two dissimilar metals, then a
static temperature differential applied between the contact points of
the two dissimilar metals DOES induce an electric current in the
circuit, and this current continues to flow for as long as the static
temperature differential is maintained. And of course the equivalent
of this phenomenon when applied to an inhomogeneous material such as a
dental amalgam is that the static temperature differential should be
expected to induce and sustain "thermeoelectric" eddy currents around
the inclusions of dissimilar metal which are internal to the material
itself.

I don't know whether this stuff is included under the description
"elementary physics" or not. Though it does appear that dental
students in dental schools are never taught it. Nevertheless, it makes
me wonder whether or not the reverse analogy is also true for static
magnetic fields when applied to inhomogeneous mixtures of metals, and
that these too might be able to induce eddy currents in dental
amalgams.

Food for thought.

If only we had some experimental evidence which might settle the issue
either way.

Whatever the case, I'd advise anyone who might be feeling the urge to
step into the role of "expert on the electromagnetic behavior of
dental amalgams" at this point to be very careful.

Because I for one can feel the rumblings of a next question which
might be on the lines of, "and are you presuming that static
electromagnetic fields are the only kind that metal dental
restorations are subjected to?".

"Elementry physics" my eye!

Keith P Walsh

"Olin Perry Norton" <mylastname[at]icet.msstate.invalid> wrote in message
news:gm7nk8$eol$1[at]nntp.msstate.edu...
- quote -


By analogy, it would be hard for you to "see" how a pebble could
topple a boy on a skateboard (any effect whatsoever) when a boulder
or brick wall would stop him dead. Perhaps you do not want to see.




- quote -

It seems to me that we go for several months without
hearing from Mr. Walsh, and then he resurfaces with
a post of basically the same stuff he posted the previous
time around.

Has anyone determined the period of the Walsh function?
Is it correlated with the phase of the moon, perhaps?

At any rate, during a previous iteration, Mr. Walsh
gave us a reference to a paper on the eddy currents induced
inside a metallic conductor which contains an inclusion of
a different metal and is subjected to a temperature gradient.

Let's see, when was that ... ah yes, it was back in October 2006.

In the paper Mr. Walsh referred us to then, the authors considered
a copper-constantan system. If one had a block of copper
with a constantan inclusion, and if that block were subjected to
a temperature gradient, then there would be a steady, DC eddy
current flowing inside the block of metal, due to the thermoelectric
effect and the fact that one end of the inclusion would be at a
different temperature than the other end due to the temperature
gradient.

This would presumably occur inside any conductor which was not
of homogeneous composition (i.e., a dental amalgam) and was
subjected to a temperature gradient.

I pointed out at the time that the external manifestation of
this eddy current was a very, very small (pT, that's
right -- PICO-Tesla -- PICO, as in 10^-12)
steady magnetic field. This result was stated in the very
paper Mr. Walsh referred us to, but somehow he seemed to
have missed it in his reading. This is an extremely
tiny magnetic field, many orders of magnitude less than
the earth's magnetic field, and it is hard to see how it would
have any effect whatsoever on the human body.

In fact, the authors of Mr. Walsh's reference stated that
"only the most sensitive magnetometers have a significant
chance to detect the expected magnetic field values at a
proper signal to noise ratio." This magnetic field is so
tiny that you would need a SQUID detector to have any chance
of even measuring it.

So, how could this extremely weak DC magnetic field, many
orders of magnitude less than the already existing DC
magnetic field of the earth, possibly have any effect on the
human body?

I seem to recall that Mr. Walsh ignored this question back in
2006.

Olin Perry Norton

On 28 Jan, 19:41, alchazz <no.s...[at]wanted.com> wrote:

- quote -

Sorry to labor the point Al, but I found my other favorite reference
for gallium amalgams (i.e. where the liquid metal used to formulate
the amalgam is gallium and not mercury - so there's no mercury in
'em).

This is from the Institute of Physics document service website at:

http://www.priorartdatabase.com/IPCOM/000137544/

"Hermetic Sealing of Electronic Hardware Using Gallium Amalgams

In this proposed invention, the gallium amalgam is mixed in a ball
mill, but the mixing action is minimized to limit the abrasion of the
metal particles so as not to have the liquid gallium wet the metal
particles. Since the metal particles are not wetted by the liquid
gallium, they will not dissolve in the liquid gallium. The pot life is
thus much extended. The liquid gallium, laden with metal particles, is
placed on the surfaces to be joined. The faying surfaces are pressed
together and then vibrated with respect to each other. The compressive
stresses and relative motion between the surfaces cause the metal
particles to abrade against each other and the faying surfaces. The
particles and the faying surfaces become clean and thus wettable by
the liquid gallium. The amalgamation process begins solidifying the
amalgam and joining the two surfaces. When the amalgamation process is
complete, the amalgam becomes solid and holds the faying surfaces
together.

The amalgam can be a ternary alloy having 5-35% Cu and 15-30% Ni in
liquid gallium. The nickel and copper particle size has to be less
than about 0.05 mm so that the faying surfaces are not kept
excessively apart by the particles. The relative motion between the
faying surfaces to initiate the amalgamation action can be achieved
by..."

So you see there really are amalgams with no mercury in them - but it
is still correct to call them amalgams because of the nature of the
process by which they are formed.

But like I said, yours is a common misconception, so there's no need
to feel stupid.

On the other hand, if you begin to wonder whether the idea that
"there's nothing wrong metal amalgam dental fillings" might also be a
common misconception let me know and I'll give you some pointers on
how you might find out.

Keith P Walsh

Keith P Walsh wrote, On 1/31/2009 3:30 AM:
- quote -

thermoelectric effect across an thermal gradient in an amalgam. Do the
experiment and find out for yourself.

--

Paul D Oosterhout
I work for SAIC (but I don't speak for SAIC)

On 28 Jan, 19:41, alchazz <no.s...[at]wanted.com> wrote:

- quote -

That's a common misconception.

That "an amalgam" has come to imply mercury, particularly in the
dental profession, is because mercury amalgams are the most common.

But mercury amalgams are NOT the only type of amalgam, as you can see
by extracts from the book, "Principles of Soldering", by Giles
Humpston and David M Jacobson, published by ASM International (April
2004) and endorsed by The Materials Information Society.

The parts which are of interest to us are:

Page 115 - Section 5.4.1 - Amalgams Based on Mercury

Page 116 - Section 5.4.2 - Amalgams Based on Gallium

"Gallium melts at 29 deg C and is therefore a potential base for
formulating very low-process-temperature amalgams without the toxic
hazard associated with mercury"

(Note, there's no mercury in these amalgams.)

Page 117 - Section 5.4.3 - Amalgams Based on Indium

"Indium is another liquid metal that can be considered as a base for
amalgam systems. "

(There's no mercury in these amalgams either.)

You can find details of this book at:

http://books.google.com/books?id=cQ6...OWq3Uw#PPP1,M1

When I first quoted these pages (see message in thread "Lessons on
Alloys, Amalgams, and Pleonasms (2)" of 1 September 2007)
they were available for reading at the above URL.

Unfortunately it looks like since then they've been made unavailable!
(I tell ya, if I were a conspiracy theorist ... ).

Anyway the quotes are genuine.

So come on Al. Please don't simply ignore this post just because
you've been proved wrong.

Get typing and give us your opinion now (and don't be shy about cross-
posting to the other groups).

Keith P Walsh