I had a tooth extracted today. It had been crowned with gold. They gave me
back the gold crown, tooth still in it of course.

I seem to recall hearing that Coca-Cola actually dissolves teeth. Is that
a workable solution to removing the old tooth from the gold crown? Is
there a better one?

Grant

In article 1e4mk.309$xv.240@trnddc02, Grant Erwin wrote:
I had a tooth extracted today. It had been crowned with gold. They gave me
back the gold crown, tooth still in it of course.

I seem to recall hearing that Coca-Cola actually dissolves teeth. Is that
a workable solution to removing the old tooth from the gold crown? Is
there a better one?

The coke doesn't work. I am in the same boat, and it barely touched the
tooth (if at all) before it went moldy.

Still looking for a good approach...

Doug White

"Grant Erwin" wrote: (clip) I seem to recall hearing that Coca-Cola
actually dissolves teeth. Is that
a workable solution to removing the old tooth from the gold crown? Is
there a better one?
^^^^^^^^^^^^^^^^^^
It must be pretty slow--else most of the population would be toothless. I
suggest tap-tap-tap with a small hammer. Or leave the tooth in, and have a
jeweler add a small ring, so you can wear it on a chain around your neck.
:-)

Grant Erwin wrote:
I had a tooth extracted today. It had been crowned with gold. They gave me
back the gold crown, tooth still in it of course.

I seem to recall hearing that Coca-Cola actually dissolves teeth. Is that
a workable solution to removing the old tooth from the gold crown? Is
there a better one?

Grant

Try heat. I think the glue would fail before the gold would melt.
RR

"Grant Erwin" wrote
in message news:1e4mk.309$xv.240@trnddc02...
I had a tooth extracted today. It had been
crowned with gold. They gave me
back the gold crown, tooth still in it of
course.

I seem to recall hearing that Coca-Cola
actually dissolves teeth. Is that
a workable solution to removing the old tooth
from the gold crown? Is
there a better one?

Grant

Try a stronger acid. The Phosphoric and Citric
acids in Coke are weak and slow.

Maybe HCL/Muriatic? Might even try a little
battery electrolyte --that's
Sulfuric.

Don't try a mix of Nitric and Sulfuric:-)

Grant Erwin writes:

Is that a workable solution to removing the old tooth from the gold
crown?

No.

Is there a better one?

Melt it out with a propane torch. Improvise a casting crucible by grinding
and compressing bentonite clay (hidden in the grocery store disguised as
the cheapest unscented store-brand kitty litter). Or from silicate furnace
cement.

Gold dealers will give you about half the bullion value of the gold scrap.
They're in it for a profit. Likely no more than $50 or $100 cash for an
old crown, so it may not even be worth the trouble. But you could play
with the jewelry style of metalworking, say casting and finishing a finger
ring.

On Tue, 05 Aug 2008 22:28:14 GMT, (Doug White)
wrote:

The coke doesn't work. I am in the same boat, and it barely touched the
tooth (if at all) before it went moldy.

Still looking for a good approach...

Dilute HCl, .1 N dissolves Hydroxyapatite. In the absence of nitrate,
this will not dissolve the gold, though it may extract alloying metals
such as copper from the surface, leaving a frosty surface.
You can speed this up in a beaker floating in an ultrasonic cleaner.
This cavitates the organic materials as well as speeding up the
dissolution of the HA.

Coke will not work because it is a very dilute solution of phosphoric
acid, which gave rise to stories about it removing rust from bumpers.

HA can be prepared from H3PO4 and CaOH2 .

BillM wrote:

Don't try a mix of Nitric and Sulfuric:-)

Or Nitric and Hydrochloric = Aqua Regia. :-)
...lew...

"Lew Hartswick" wrote
in message
m...
BillM wrote:

Don't try a mix of Nitric and Sulfuric:-)
Or Nitric and Hydrochloric = Aqua Regia. :-)
...lew..

My bad. For some reason I had it in my head
that Aqua Regia was nitric/sulfuric.

Bill.

"Grant Erwin" wrote in message
news:1e4mk.309$xv.240@trnddc02...
I had a tooth extracted today. It had been crowned with gold. They gave me
back the gold crown, tooth still in it of course.

I seem to recall hearing that Coca-Cola actually dissolves teeth. Is that
a workable solution to removing the old tooth from the gold crown? Is
there a better one?

Grant

Hammer.

Tom Gardner wrote:
"Grant Erwin" wrote in message
news:1e4mk.309$xv.240@trnddc02...

I had a tooth extracted today. It had been crowned with gold. They gave me
back the gold crown, tooth still in it of course.

I seem to recall hearing that Coca-Cola actually dissolves teeth. Is that
a workable solution to removing the old tooth from the gold crown? Is
there a better one?

Grant


Hammer.



That's kind of what I am thinking. I'll try that tomorrow, let you know
what happened.

Grant

"Grunty Grogan" wrote in message
...
On Tue, 05 Aug 2008 22:28:14 GMT, (Doug White)
wrote:

The coke doesn't work. I am in the same boat, and it barely touched the
tooth (if at all) before it went moldy.

Still looking for a good approach...

Dilute HCl, .1 N dissolves Hydroxyapatite. In the absence of nitrate,
this will not dissolve the gold, though it may extract alloying metals
such as copper from the surface, leaving a frosty surface.
You can speed this up in a beaker floating in an ultrasonic cleaner.
This cavitates the organic materials as well as speeding up the
dissolution of the HA.

Coke will not work because it is a very dilute solution of phosphoric
acid, which gave rise to stories about it removing rust from bumpers.

HA can be prepared from H3PO4 and CaOH2 .

EDTA might work. Dissolves egg shells readily.
--
DT

On Wed, 06 Aug 2008 05:44:26 GMT, Grant Erwin
wrote:

Tom Gardner wrote:
"Grant Erwin" wrote in message
news:1e4mk.309$xv.240@trnddc02...

I had a tooth extracted today. It had been crowned with gold. They gave me
back the gold crown, tooth still in it of course.

I seem to recall hearing that Coca-Cola actually dissolves teeth. Is that
a workable solution to removing the old tooth from the gold crown? Is
there a better one?

Grant


Hammer.



That's kind of what I am thinking. I'll try that tomorrow, let you know
what happened.

Grant
A propane torch will just burn out the tooth from the gold.
ERS

On Wed, 6 Aug 2008 01:22:12 -0400, with neither quill nor qualm, "Tom
Gardner" quickly quoth:


"Grant Erwin" wrote in message
news:1e4mk.309$xv.240@trnddc02...
I had a tooth extracted today. It had been crowned with gold. They gave me
back the gold crown, tooth still in it of course.

I seem to recall hearing that Coca-Cola actually dissolves teeth. Is that
a workable solution to removing the old tooth from the gold crown? Is
there a better one?

Grant

Hammer.

What, and ruin the shape of the thing you're selling to be melted?

---
Chaos, panic, and disorder--my work here is done.

In article ,
wrote:

On Wed, 06 Aug 2008 05:44:26 GMT, Grant Erwin
wrote:

Tom Gardner wrote:
"Grant Erwin" wrote in message
news:1e4mk.309$xv.240@trnddc02...

I had a tooth extracted today. It had been crowned with gold. They gave me
back the gold crown, tooth still in it of course.

I seem to recall hearing that Coca-Cola actually dissolves teeth. Is that
a workable solution to removing the old tooth from the gold crown? Is
there a better one?

Grant


Hammer.



That's kind of what I am thinking. I'll try that tomorrow, let you know
what happened.

Grant
A propane torch will just burn out the tooth from the gold.

Beware mercury fumes. The gold in crowns may be or contain mercury-gold
amalgam, not just gold-copper casting alloy.

Joe Gwinn

I had a tooth extracted today. It had been crowned with gold. They
gave me
back the gold crown, tooth still in it of course.

I seem to recall hearing that Coca-Cola actually dissolves teeth. Is
that
a workable solution to removing the old tooth from the gold crown? Is
there a better one?

Grant

That's kind of what I am thinking. I'll try that tomorrow, let you know
what happened.

Grant
A propane torch will just burn out the tooth from the gold.

Beware mercury fumes. The gold in crowns may be or contain mercury-gold
amalgam, not just gold-copper casting alloy.

Joe Gwinn

why not tap with a hammer and break up the tooth - the gold is maleable and
the tooth is not


** Posted from http://www.teranews.com **

Joseph Gwinn wrote:
In article ,
wrote:

On Wed, 06 Aug 2008 05:44:26 GMT, Grant Erwin
wrote:

Tom Gardner wrote:
"Grant Erwin" wrote in message
news:1e4mk.309$xv.240@trnddc02...

I had a tooth extracted today. It had been crowned with gold. They gave me
back the gold crown, tooth still in it of course.

I seem to recall hearing that Coca-Cola actually dissolves teeth. Is that
a workable solution to removing the old tooth from the gold crown? Is
there a better one?

Grant

Hammer.


That's kind of what I am thinking. I'll try that tomorrow, let you know
what happened.

Grant
A propane torch will just burn out the tooth from the gold.

Beware mercury fumes. The gold in crowns may be or contain mercury-gold
amalgam, not just gold-copper casting alloy.

Joe Gwinn


Gold crowns are not made from amalgams. Gold amalgams are used for
fillings. Silver amalgam fillings are always removed before a tooth is
crowned.

The reason that an amalgam filled tooth gets a crown in the first place,
is mostly, that there is new decay around or even under the filling, so
the tooth has to be cleaned and the amalgam is removed to make place for
either an inlay, overlay or a full crown. You cannot prep a tooth
properly for a crown, with the amalgam still in place.

It not necessary to put a torch to a tooth with a crown still on it.
Since the tooth has already been extracted, it will have become brittle
rather rapidly, because it is no longer fed by blood vessels and nerves.
Just take a pair of pliers to it, and it'll break in pieces quite easily.

BTW, before I became a goldsmith, I spent three years in dental school
at the university of Amsterdam trying to become a dentist.

--
Abrasha
http://www.abrasha.com

Abrasha wrote:

Joseph Gwinn wrote:

In article ,
wrote:

On Wed, 06 Aug 2008 05:44:26 GMT, Grant Erwin
wrote:

Tom Gardner wrote:

"Grant Erwin" wrote in message
news:1e4mk.309$xv.240@trnddc02...

I had a tooth extracted today. It had been crowned with gold. They
gave me
back the gold crown, tooth still in it of course.

I seem to recall hearing that Coca-Cola actually dissolves teeth.
Is that
a workable solution to removing the old tooth from the gold crown? Is
there a better one?

Grant


Hammer.

That's kind of what I am thinking. I'll try that tomorrow, let you know
what happened.

Grant

A propane torch will just burn out the tooth from the gold.


Beware mercury fumes. The gold in crowns may be or contain
mercury-gold amalgam, not just gold-copper casting alloy.

Joe Gwinn



Gold crowns are not made from amalgams. Gold amalgams are used for
fillings. Silver amalgam fillings are always removed before a tooth is
crowned.

The reason that an amalgam filled tooth gets a crown in the first place,
is mostly, that there is new decay around or even under the filling, so
the tooth has to be cleaned and the amalgam is removed to make place for
either an inlay, overlay or a full crown. You cannot prep a tooth
properly for a crown, with the amalgam still in place.

It not necessary to put a torch to a tooth with a crown still on it.
Since the tooth has already been extracted, it will have become brittle
rather rapidly, because it is no longer fed by blood vessels and nerves.
Just take a pair of pliers to it, and it'll break in pieces quite easily.

BTW, before I became a goldsmith, I spent three years in dental school
at the university of Amsterdam trying to become a dentist.


I put the crown, tooth in it, in a bench vise, minor closure, CRACK, all
the tooth pieces fell out. Took about 3 seconds flat.

Now I have 2.7 grams of gold crown and another couple grams of whatever alloy
they use under ceramic. Oh, the bench vise cracked off about 95% of the ceramic
too, on that one.

Grant

In article ,
Abrasha wrote:

Joseph Gwinn wrote:
In article ,
wrote:

On Wed, 06 Aug 2008 05:44:26 GMT, Grant Erwin
wrote:

Tom Gardner wrote:
"Grant Erwin" wrote in message
news:1e4mk.309$xv.240@trnddc02...

I had a tooth extracted today. It had been crowned with gold. They gave
me
back the gold crown, tooth still in it of course.

I seem to recall hearing that Coca-Cola actually dissolves teeth. Is
that
a workable solution to removing the old tooth from the gold crown? Is
there a better one?

Grant

Hammer.


That's kind of what I am thinking. I'll try that tomorrow, let you know
what happened.

Grant
A propane torch will just burn out the tooth from the gold.

Beware mercury fumes. The gold in crowns may be or contain mercury-gold
amalgam, not just gold-copper casting alloy.

Joe Gwinn


Gold crowns are not made from amalgams. Gold amalgams are used for
fillings. Silver amalgam fillings are always removed before a tooth is
crowned.

The reason that an amalgam filled tooth gets a crown in the first place,
is mostly, that there is new decay around or even under the filling, so
the tooth has to be cleaned and the amalgam is removed to make place for
either an inlay, overlay or a full crown. You cannot prep a tooth
properly for a crown, with the amalgam still in place.

It not necessary to put a torch to a tooth with a crown still on it.
Since the tooth has already been extracted, it will have become brittle
rather rapidly, because it is no longer fed by blood vessels and nerves.
Just take a pair of pliers to it, and it'll break in pieces quite easily.

BTW, before I became a goldsmith, I spent three years in dental school
at the university of Amsterdam trying to become a dentist.

I don't doubt that you have described how it is supposed to be. But the
world isn't perfect, and there is no cost to being a little cautious
while heating the gold alloy. It might be contaminated if the dentist
didn't get all the amalgam out.

Joe Gwinn

Joseph Gwinn wrote:


It might be contaminated if the dentist
didn't get all the amalgam out.

This is almost impossible. However, in the unlikely event, that this
was the case, the work was done by an exceptionally bad dentist.

Getting old silver amalgam fillings out, is quite easy, since the moment
they are touched with a drill, they pretty much crumble and get ripped
out. The pieces fly in all directions (inside the mouth of course),
because of the characteristics of the material once it has been in a
tooth for some time.

It is also very likely, that if in fact there was still some silver
amalgam left under the crown, the patient would have developed new decay
and with it quite a severe toothache. The crown would have failed, have
to be removed, the tooth would have to be cleaned again, and a new crown
would have to be made and placed.

Also, if he did choose to heat it, the cement with which the crown is
affixed to the tooth would decompose long before the gold would melt.

And lastly, even if there were a silver amalgam filling under the crown,
heating it would most likely be harmless. It is unlikely that he is
going to get hurt from "Mercury vapors" from a single silver amalgam
filling.

A mouthful of silver amalgam fillings is a lot more dangerous to a
person's sustained health, than heating one that is no longer in a mouth.

http://zakstar.wordpress.com/2008/01...lgam-fillings/

Before the advent of electroplating, precious metal smiths used the
extremely poisonous technique of "fire gilding" to gold plate silver
objects. This was done with gold amalgams.

--
Abrasha
http://www.abrasha.com

In article ,
Abrasha wrote:

Joseph Gwinn wrote:


It might be contaminated if the dentist
didn't get all the amalgam out.

This is almost impossible. However, in the unlikely event, that this
was the case, the work was done by an exceptionally bad dentist.

Getting old silver amalgam fillings out, is quite easy, since the moment
they are touched with a drill, they pretty much crumble and get ripped
out. The pieces fly in all directions (inside the mouth of course),
because of the characteristics of the material once it has been in a
tooth for some time.

It is also very likely, that if in fact there was still some silver
amalgam left under the crown, the patient would have developed new decay
and with it quite a severe toothache. The crown would have failed, have
to be removed, the tooth would have to be cleaned again, and a new crown
would have to be made and placed.

Also, if he did choose to heat it, the cement with which the crown is
affixed to the tooth would decompose long before the gold would melt.

And lastly, even if there were a silver amalgam filling under the crown,
heating it would most likely be harmless. It is unlikely that he is
going to get hurt from "Mercury vapors" from a single silver amalgam
filling.

A mouthful of silver amalgam fillings is a lot more dangerous to a
person's sustained health, than heating one that is no longer in a mouth.

http://zakstar.wordpress.com/2008/01...lgam-fillings/

Well, it's far too late for me.


Before the advent of electroplating, precious metal smiths used the
extremely poisonous technique of "fire gilding" to gold plate silver
objects. This was done with gold amalgams.

I had not heard of this technique. If it was before electroplating, it
was back when an old man was 45, so they probably didn't manage to die
of the mercury fumes.

I recall reading that the ancients knew how to electroplate, although
they didn't understand how or why it worked.

Joe Gwinn

Joe Gwinn

Joseph Gwinn wrote:



Before the advent of electroplating, precious metal smiths used the
extremely poisonous technique of "fire gilding" to gold plate silver
objects. This was done with gold amalgams.

I had not heard of this technique.

http://en.wikipedia.org/wiki/Gilding#Fire-gilding


"Fire gilding: A perilous process for gold-plating in which an amalgam
of mercury and gold is applied to an object and then exposed to heat to
vaporize the mercury and leave the gold behind in a thin layer. Fire
gilding also is applicable to plating silver, copper, and copper alloys.
The process of fie gilding is still used when antique work is to be
repaired or an exact replica made. Fire gilding is hazardous because
mercury vapors are emitted even at room temperature, presenting an
appreciable risk of mercury poisoning. Fire gilding is also called
mercury gilding."
http://www.medterms.com/script/main/...ticlekey=39600


"The practice of amalgam gilding goes back many centuries. It was used
by the Romans to apply gold onto silver, known as silver-gilt (Maryon
1971, p. 262), and in his twelfth-century book, On Divers Arts,
Theophilus describes in detail how to gild a surface using an amalgam.
An amalgam is any alloy of mercury with another metal, in this case gold."
http://www.metmuseum.org/toah/hd/fire/hd_fire.htm

If it was before electroplating, it
was back when an old man was 45, so they probably didn't manage to die
of the mercury fumes.

They did in fact die of the cumulative effects of serious Mercury
poisoning. BTW, the expression "Mad as a hatter" comes from the use of
Mercury in the making of felt for the hat industry.


"Few people who use the phrase today realise that there’s a story of
human suffering behind it; the term derives from an early industrial
occupational disease. Felt hats were once very popular in North America
and Europe; an example is the top hat. The best sorts were made from
beaver fur, but cheaper ones used furs such as rabbit instead.

A complicated set of processes was needed to turn the fur into a
finished hat. With the cheaper sorts of fur, an early step was to brush
a solution of a mercury compound — usually mercurous nitrate — on to the
fur to roughen the fibres and make them mat more easily, a process
called carroting because it made the fur turn orange. Beaver fur had
natural serrated edges that made this unnecessary, one reason why it was
preferred, but the cost and scarcity of beaver meant that other furs had
to be used.

Whatever the source of the fur, the fibres were then shaved off the skin
and turned into felt; this was later immersed in a boiling acid solution
to thicken and harden it. Finishing processes included steaming the hat
to shape and ironing it. In all these steps, hatters working in poorly
ventilated workshops would breathe in the mercury compounds and
accumulate the metal in their bodies.

We now know that mercury is a cumulative poison that causes kidney and
brain damage."
http://www.worldwidewords.org/qa/qa-mad2.htm


I recall reading that the ancients knew how to electroplate, although
they didn't understand how or why it worked.


"The early history of electroplating may be traced back to around 1800.
A university professor, or in modern terms: a chemist, Luigi Brugnatelli
is considered as the first person to apply electrodeposition process to
electroplate gold. Brugnatelli was a friend of Allisandro Volta (after
whom the electric unit "volt" has been named) who had just a short time
before discovered the chemical principles that would make possible the
development of "voltaic" electrical cells. Volta's first actual
demonstration of that was called "Voltaic Pile". As a consequence of
this development, Brugnatelli's early work using voltaic electricity
enabled him to experiment with various plating solutions. By 1805 he had
refined his process enough to plate a fine layer of gold over large
silver metal objects."
http://electrochem.cwru.edu/ed/encyc...lectroplat.htm


"Modern electrochemistry was invented by Italian chemist Luigi V.
Brugnatelli in 1805. Brugnatelli used his colleague Alessandro Volta's
invention of five years earlier, the voltaic pile, to facilitate the
first electrodeposition. Brugnatelli's inventions were repressed by the
French Academy of Sciences and did not become used in general industry
for the following thirty years."
http://en.wikipedia.org/wiki/Electroplating#History

--
Abrasha
http://www.abrasha.com

In article ,
Abrasha wrote:

Joseph Gwinn wrote:



Before the advent of electroplating, precious metal smiths used the
extremely poisonous technique of "fire gilding" to gold plate silver
objects. This was done with gold amalgams.

I had not heard of this technique.

http://en.wikipedia.org/wiki/Gilding#Fire-gilding

[snip]

If it was before electroplating, it
was back when an old man was 45, so they probably didn't manage to die
of the mercury fumes.

They did in fact die of the cumulative effects of serious Mercury
poisoning. BTW, the expression "Mad as a hatter" comes from the use of
Mercury in the making of felt for the hat industry.

Good lord. That would be able to kill them way before the diseases
usual in the day.


[snip]
I recall reading that the ancients knew how to electroplate, although
they didn't understand how or why it worked.


"The early history of electroplating may be traced back to around 1800.
A university professor, or in modern terms: a chemist, Luigi Brugnatelli
is considered as the first person to apply electrodeposition process to
electroplate gold. Brugnatelli was a friend of Allisandro Volta (after
whom the electric unit "volt" has been named) who had just a short time
before discovered the chemical principles that would make possible the
development of "voltaic" electrical cells. Volta's first actual
demonstration of that was called "Voltaic Pile". As a consequence of
this development, Brugnatelli's early work using voltaic electricity
enabled him to experiment with various plating solutions. By 1805 he had
refined his process enough to plate a fine layer of gold over large
silver metal objects."
http://electrochem.cwru.edu/ed/encyc...lectroplat.htm


"Modern electrochemistry was invented by Italian chemist Luigi V.
Brugnatelli in 1805. Brugnatelli used his colleague Alessandro Volta's
invention of five years earlier, the voltaic pile, to facilitate the
first electrodeposition. Brugnatelli's inventions were repressed by the
French Academy of Sciences and did not become used in general industry
for the following thirty years."
http://en.wikipedia.org/wiki/Electroplating#History

The articles I read many years ago were talking about ancient Egypt or
China, at least 1000 years before the 1800s, well before the invention
of the battery by Volta in Italy. What was described was a battery and
plating cell all in one. It might have been for copper plating. It was
clear that ancients did not understand why the thing worked, only how to
replicate it.

Joe Gwinn

"Joseph Gwinn" wrote in message
...
http://en.wikipedia.org/wiki/Electroplating#History

The articles I read many years ago were talking about ancient Egypt or
China, at least 1000 years before the 1800s, well before the invention
of the battery by Volta in Italy. What was described was a battery and
plating cell all in one. It might have been for copper plating. It was
clear that ancients did not understand why the thing worked, only how to
replicate it.

Joe Gwinn

Your probably thinking of the Baghdad batteries.

These were ancient ceramic jars with a tar seal and a sheet of copper and an
iron rod inside.

Speculation in some circles goes something like this:

"What the hell are these things?"
"Could be a battery."
"What the hell did they need a battery for, they didn't have any transistor
radios?"
"They must have invented electroplating!"

Anyone who has made a battery for a science fair project knows that iron and
copper have only about 3/8 v potential between them and make a pretty crappy
battery.

If you wanted to do any plating, you would need at least a dozen of them in
series. If the ancient Mesopotamians knew the difference between series and
parallel.

Paul K. Dickman

Paul K. Dickman wrote:
"Joseph Gwinn" wrote in message
...

http://en.wikipedia.org/wiki/Electroplating#History

The articles I read many years ago were talking about ancient Egypt or
China, at least 1000 years before the 1800s, well before the invention
of the battery by Volta in Italy. What was described was a battery and
plating cell all in one. It might have been for copper plating. It was
clear that ancients did not understand why the thing worked, only how to
replicate it.

Joe Gwinn


Your probably thinking of the Baghdad batteries.

These were ancient ceramic jars with a tar seal and a sheet of copper and an
iron rod inside.

Speculation in some circles goes something like this:

"What the hell are these things?"
"Could be a battery."
"What the hell did they need a battery for, they didn't have any transistor
radios?"
"They must have invented electroplating!"

Anyone who has made a battery for a science fair project knows that iron and
copper have only about 3/8 v potential between them and make a pretty crappy
battery.

If you wanted to do any plating, you would need at least a dozen of them in
series. If the ancient Mesopotamians knew the difference between series and
parallel.

Paul K. Dickman


Apparently they did know the difference:

"In 1936, at Khujut Rabu'a near Baghdad, was found a small pottery jar, about 5-1/2
inches high and 31 inches in diameter. Inside was a cylinder of thin copper, closed
by an asphalt plug. Inside the cylinder was a rusted iron rod.
Similar jars, without the metal cylinders and rods, had been found at the ruins of
Seleucia-on-the- Tigris, twenty-four miles below Baghdad.
Three larger jars containing respectively ten copper cylinders, ten iron rods, and ten
asphalt plugs, not yet assembled as in the Khujut Rabu'a jar, turned up at Ctesiphon,
across the Tigris from Seleucia.
All these objects date approximately from Roman Imperial times. The only use that
anybody has been able to conceive for them is as battery cells for electroplating small
metal objects with gold.
It has also transpired that the silversmiths of Baghdad, within the present century,
used a similar apparatus for gold-plating their works. Those who knew about this
method long assumed that the silversmiths had learned their electroplating from western
sources. Although ar*cheologists are not yet agreed about the mysterious jars, we must
at least consider the strange possibility that electroplating was discovered in Iraq in
ancient times; that, despite the ravages of the Mongols in + XIII, this technique
survived down to the present century; and that, nevertheless, it failed to spread
to other lands, presumably because the metal workers kept it secret."

"The Ancient Engineers", L Sprague Le Camp, 1960

Tom

In article , Tom wrote:

Paul K. Dickman wrote:
"Joseph Gwinn" wrote in message
...

http://en.wikipedia.org/wiki/Electroplating#History

The articles I read many years ago were talking about ancient Egypt or
China, at least 1000 years before the 1800s, well before the invention
of the battery by Volta in Italy. What was described was a battery and
plating cell all in one. It might have been for copper plating. It was
clear that ancients did not understand why the thing worked, only how to
replicate it.

Joe Gwinn


Your probably thinking of the Baghdad batteries.

These were ancient ceramic jars with a tar seal and a sheet of copper and
an
iron rod inside.

Speculation in some circles goes something like this:

"What the hell are these things?"
"Could be a battery."
"What the hell did they need a battery for, they didn't have any transistor
radios?"
"They must have invented electroplating!"

Anyone who has made a battery for a science fair project knows that iron
and
copper have only about 3/8 v potential between them and make a pretty
crappy
battery.

If you wanted to do any plating, you would need at least a dozen of them in
series. If the ancient Mesopotamians knew the difference between series and
parallel.

Paul K. Dickman


Apparently they did know the difference:

"In 1936, at Khujut Rabu'a near Baghdad, was found a small pottery jar, about
5-1/2
inches high and 31 inches in diameter. Inside was a cylinder of thin
copper, closed
by an asphalt plug. Inside the cylinder was a rusted iron rod.
Similar jars, without the metal cylinders and rods, had been found at the
ruins of
Seleucia-on-the- Tigris, twenty-four miles below Baghdad.
Three larger jars containing respectively ten copper cylinders, ten iron
rods, and ten
asphalt plugs, not yet assembled as in the Khujut Rabu'a jar, turned up at
Ctesiphon,
across the Tigris from Seleucia.
All these objects date approximately from Roman Imperial times. The only
use that
anybody has been able to conceive for them is as battery cells for
electroplating small
metal objects with gold.
It has also transpired that the silversmiths of Baghdad, within the present
century,
used a similar apparatus for gold-plating their works. Those who knew about
this
method long assumed that the silversmiths had learned their electroplating
from western
sources. Although ar*cheologists are not yet agreed about the mysterious
jars, we must
at least consider the strange possibility that electroplating was
discovered in Iraq in
ancient times; that, despite the ravages of the Mongols in + XIII, this
technique
survived down to the present century; and that, nevertheless, it failed to
spread
to other lands, presumably because the metal workers kept it secret."

"The Ancient Engineers", L Sprague Le Camp, 1960

Tom

Bingo! This is exactly what I was remembering.

Joe Gwinn

Ifeel that I have to set the record straight:

Current practice in dentistry is to remove decay and old fillings before
preparing a tooth for a crown.
The next step typically is to rebuild the tooth. This can be done with
composite materials or silver-mercury amalgam. The tooth is then shaped for
the crown and an impression is taken. The result can be a crown over an
existing mercury filling. This is accepted practice in the USA.
In the past gold crowns have been done over existing old mercury fillings
for many different reasons.
When you heat the gold crown on a tooth you have no idea if there is mercury
present underneath. The heat required to melt the gold will either
volatilize the mercury or create a gold amalgam. Neither is good for you:
the mercury vapor is toxic and the amalgam will release the mercury when it
is heated the next time for casting.

In the US I am not aware of the teaching of gold amalgam in dentistry in the
last 50 years.

There is no way to economically cash in a gold crown. Your best choice is
to play with it and make something. The Karat content of the gold varies
all over the place. I suppose the standard gold tests would let you know
what it is.

Charles Friedman DDS
Ventura by the Sea where we extract black gold from the ground






I had a tooth extracted today. It had been crowned with gold. They
gave me
back the gold crown, tooth still in it of course.

I seem to recall hearing that Coca-Cola actually dissolves teeth. Is
that
a workable solution to removing the old tooth from the gold crown?
Is
there a better one?

Grant

Hammer.


A propane torch will just burn out the tooth from the gold.

Beware mercury fumes. The gold in crowns may be or contain mercury-gold
amalgam, not just gold-copper casting alloy.


Gold crowns are not made from amalgams. Gold amalgams are used for
fillings. Silver amalgam fillings are always removed before a tooth is
crowned.

The reason that an amalgam filled tooth gets a crown in the first place,
is mostly, that there is new decay around or even under the filling, so
the tooth has to be cleaned and the amalgam is removed to make place for
either an inlay, overlay or a full crown. You cannot prep a tooth
properly for a crown, with the amalgam still in place.

It not necessary to put a torch to a tooth with a crown still on it.
Since the tooth has already been extracted, it will have become brittle
rather rapidly, because it is no longer fed by blood vessels and nerves.
Just take a pair of pliers to it, and it'll break in pieces quite
easily.

BTW, before I became a goldsmith, I spent three years in dental school
at the university of Amsterdam trying to become a dentist.