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  #21  
Old April 22nd 07, 03:55 AM posted to rec.crafts.jewelry
Bob
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Posts: 14
Default granulation

On Apr 19, 10
Still, I'm curious. Can you explain how Ronda does it?

thanks.

Peter Rowe


Hi, Peter --

I've take both of Rhonda's classes in granulation, and she teaches
slightly different techniques for fine silver and for gold. For
silver, no copper or other metallic salts are involved. I believe
it's just finely controlled fusion. She uses a fine silver base and
fine silver granules. The "glue" is a mixture of green flux, hide
glue, and water. Granules are placed wet with a fine brush, the piece
then dried on top of the beehive kiln until the glue carbonizes, then
it is fused in the kiln with a delicate application of direct torch
heat from above. It's normal for students to partially or completely
melt the first couple of pieces -- I think it's her way of teaching
fine control of the torch heat. Once you can consistently fuse the
silver pieces, gold becomes easy.

For 22 kt gold granulation, she DOES copper-plate the granules, and
also brings up a 24 kt surface on the substrate by repeated heating
and pickling until no oxides form. Granules are placed and fired as
described above, and the copper plating disappears during firing.

Regards,

Bob Edwards


Ads
  #22  
Old April 24th 07, 05:53 AM posted to rec.crafts.jewelry
C0nnie
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Posts: 9
Default granulation

On Apr 21, 7:55 pm, Bob wrote:
On Apr 19, 10

Still, I'm curious. Can you explain how Ronda does it?


thanks.


Peter Rowe


Hi, Peter --

I've take both of Rhonda's classes in granulation, and...


Once you can consistently fuse the
silver pieces, gold becomes easy...

.....copper plating disappears during firing.

Regards,

Bob Edwards


Peter,
Her DVD's show the technique described by Bob above. I have tried it
(not enough yet) and gotten some good results. I really like
granulation and I plan to do more. Gold granulation looks so good, I
hope to some day do some designs with it.

I would love the saliva technique because I never run out of spit. ha

Has anyone seen granulation with contrasting metals, for example gold
on silver? Or Argentium on gold? Or some other contrast?

-Connie

  #23  
Old April 25th 07, 02:15 AM posted to rec.crafts.jewelry
Don T.
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Posts: 11
Default granulation


"Peter W.. Rowe," wrote in message
...
On Tue, 17 Apr 2007 22:59:52 -0700, in rec.crafts.jewelry Carl

wrote:

When C0nnie put fingers to keys it was 3/17/07 1:56 AM...

I want to do granulation in Argentium and fine silver. I'll keep y'all
posted...

What little I know of granulation says you need to be using an alloy and
that trying to do it with fine silver will be a problem. Do I need to
know more about granulation?

- C


yes, you need to know a bit more. Fine silver, or fine gold, are the
easiest to
granulate. Alloys are increasingly difficult as their melting points
drop.

Granulation is done by causing the surface skin of the granules to melt
before
the granule itself, or the base plate, does. This is done in several
ways. One
is to copper plate the granules. The usual method is to put the grains in
an
iron cup/container, along with some well used (turned blue in color)
pickle, or
just plain copper sulphate solution (about the same thing, used pickle
that's
already at hand is of course cheaper) The resulting electrolytic action
copper
plates the grains, which can then be placed on the desired surface,
usually with
a mix of dilute orgainic glue, perhaps a trace of flux, and water. .
Another
method is to glue unplated grains in place on the backing surface with a
mix of
organic glue (hide glue, for example) often a trace of flux, and a mix of
powdered copper salts. When this is heated, to glue carbonizes, and
causes the
copper salts to reduce to metallic copper, leaving traces of copper metal
on the
grains and in the contact areas. With the plated grain method, the copper
is
already there, so no reducing action is needed. Either way, then upon
further
heating, when the eutectic temperature between copper and gold or silver
(whichever is being worked) is reached, the copper then forms a eutectic
alloys
as a liquid on the surfaces of the grains, essentially becoming a faint
thin
liquid layer of solder on the surface. It's so little that upon continued
heating, the copper quickly diffuses further into both the grains and the
substrate, leaving the grains now affixed in place.


The powdered mineral Malachite ( Chrysocolla, Copper Carbonate ), has been
used for centuries as the Copper bearing salt in granulation work and other
fusion joinings of precious metals. The name Chrysocolla translates from the
Greek to "Gold Glue". Reference to the use of the mineral as a soldering aid
is found in the writings of Theophrastus ( 370 - 287 B.C.E ). In those days
they didn't use hide glue, they used Camel dung and juices from "almost"
dried fruits ( high fructose content ) to make the granules adhere to the
intended surface and act as the supplier of additional reducing atmosphere.

--

Don Thompson

Stolen from Dan: "Just thinking, besides, I watched 2 dogs mating once,
and that makes me an expert. "

There is nothing more frightening than active ignorance.
~Goethe

It is a worthy thing to fight for one's freedom;
it is another sight finer to fight for another man's.
~Mark Twain

~~~~~~~~~~~~~~~~~~~~~
A further method, better suited to lower karats (not too low, but say,
18K) can
be done by first heating the grains repeatedly in an oxidizing atmosphere.
This
causes copper oxides to form on the surface, and copper near the surface
of the
grains to diffuse towards the surface and concentrate there as the oxide.
The
layer of metal just under the surface ends up copper depleted slightly.
In any
case, you've got a higher percentage of copper at the surface, as oxide,
than in
the alloy itself. These grains are then glued in place same as for other
methods, and heating lets for formed carbon (from the glue) reduce the
copper
skin surface to copper, and from there the process is identical.

High karat alloys, or pure metals, are easier to granulate simply because
the
difference between the temperature where bonding takes place, and that
where the
substrate or granules actually melt on their own, is greater, allowing
easier
working without melting accidents.

As to the original question, whether or not argentum silver granulates
would
depend on whether a copper layer on it's surface lowers the metling point
at the
interface between the two, and on whether the resulting eutectic bond
formed if
they grains can be affixed this way, is strong enough. Some alloys can be
granulated, but the results are not satisfactory since the joints are so
brittle
the grains fall off again too easily. I don't know if this is the case
with
argentum, but I'd not expect it to be.

fine silver, though, is relatively easy to granulate.

Peter Rowe

  #24  
Old April 25th 07, 06:37 AM posted to rec.crafts.jewelry
mbstevens
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Posts: 165
Default granulation

On Tue, 24 Apr 2007 04:53:01 +0000, C0nnie wrote:

Has anyone seen granulation with contrasting metals, for example gold
on silver? Or Argentium on gold? Or some other contrast?


http://tinyurl.com/yvs6td
....high caret gold onto sterling is quite easy because the silver melts at
a much lower temperature. No silver "solder"
such as "hard solder" is used. Still, I don't think you could call it a
fusion type of operation. I surmise what is actually going on is brazing.

You just coat everything with a light coat of Handy flux and use a
very bushy flame over coals to get the sterling to just go shimmery. I
think that if the gold granules were extremely small, the effect would
show too much silver crawling up their sides. So you are trading a
certain kind of refinement for color contrast.


  #25  
Old April 26th 07, 03:00 AM posted to rec.crafts.jewelry
Abrasha
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Posts: 298
Default granulation

To:
Subject: granulation
From: Abrasha
Date: Wed, 25 Apr 2007 09:28:22 -0700

mbstevens wrote:
On Tue, 24 Apr 2007 04:53:01 +0000, C0nnie wrote:

Has anyone seen granulation with contrasting metals, for example gold
on silver? Or Argentium on gold? Or some other contrast?


http://tinyurl.com/yvs6td
...high caret gold onto sterling is quite easy because the silver melts at
a much lower temperature. No silver "solder"
such as "hard solder" is used. Still, I don't think you could call it a
fusion type of operation. I surmise what is actually going on is brazing.


There you go again! This is NOT brazing!

A couple of definitions of what brazing is:

1: A group of welding processes that produces coalescence of materials
by heating them to the brazing temperature in the presence of a filler
metal having a liquidus above (840°F) 450°C and below the solidus of the
base metal. The filler metal is distributed between the closely fitted
faying surfaces of the joint by capillary action.
http://www.copper.org/applications/p...cal_terms.html

2: A process that is used to bond similar or dissimilar materials by
melting a filler metal or alloy that is placed between the components
being joined. Brazes are filler metals or alloys that melt at
temperatures above 450 o C.
rntfoil.com/rnt-foils/glossary.html

The emphasis is on FILLER metals!

I have asked you many times to stop dispensing "knowledge" of things you
know nothing or little of. Once again, please stop.

--
Abrasha
http://www.abrasha.com
  #26  
Old April 26th 07, 06:43 AM posted to rec.crafts.jewelry
mbstevens
external usenet poster
 
Posts: 165
Default granulation

On Thu, 26 Apr 2007 02:00:49 +0000, Abrasha wrote:

http://tinyurl.com/yvs6td
...high caret gold onto sterling is quite easy because the silver melts at
a much lower temperature. No silver "solder"
such as "hard solder" is used. Still, I don't think you could call it a
fusion type of operation. I surmise what is actually going on is brazing.


There you go again! This is NOT brazing!

A couple of definitions of what brazing is:
.............

The emphasis is on FILLER metals!


*Your* emphasis, not theirs.
A quick and rough definition of brazing will of
course tend to simplify the description of the process, demonstrating
the most typical cases.

If you understand brazing in depth, you find that the difference
between that and welding is that in welding the metals actually mix
together when both are melted at the same time. In brazing, the filler
metal, by capillary action, penetrates the porosity of another piece of
metal that does not melt. This is the important part, the part where the
emphasis *should* be placed.

The case being discussed here is not normal granulation.
In the case of attaching the high caret gold to the sterling, the
gold was not melted at all. The silver itself was the 'filler' metal.
The fact that there was not a hunk of non-melting metal on the other side
of the silver does not make it any less of a brazing operation. And it is
clearly, clearly not either a fusion weld or soft soldering. The only
reasonable term left is brazing.

I have asked you many times to stop dispensing "knowledge" of things you
know nothing or little of.


I have had course work in oxy/acetylene brazing and
welding, and have done considerable readings on the matter.

Once again, please stop.

Just as soon as you are no longer confused.
Your need to 'get' me has once again made you appear
silly and mean spirited.
--
mbstevens
http://www.mbstevens.com/






  #27  
Old April 26th 07, 06:44 AM posted to rec.crafts.jewelry
C0nnie
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Posts: 9
Default granulation

mbstevens wrote: I
think that if the gold granules were extremely small, the effect would
show too much silver crawling up their sides. So you are trading a
certain kind of refinement for color contrast.


That is very interesting. I don't mind using larger granules. I used
too-small granules on my last project. They are so small that the
overall effect is small-scale. The design is visible but not
impressive, yet the work was laborious and painstaking. The spherical
and individual nature of each granule is lost when they are as tiny as
I used.

I will try granulation with 22 K gold on Argentium or fine silver
sheet some day soon. I just need to justify the expenditure on the
gold. Perhaps more fine silver practice.

Peter,
That is all very interesting. Perhaps some day I will use some of
these materials.


  #28  
Old April 26th 07, 06:44 AM posted to rec.crafts.jewelry
mbstevens
external usenet poster
 
Posts: 165
Default granulation

On Thu, 26 Apr 2007 02:00:49 +0000, Abrasha wrote:

The emphasis is on FILLER metals!


Please stop shouting and using exclamation points.

To further illustrate the error of this argument, lets consider a common
use of brazing:

http://www.bls.gov/oco/ocos226.htm

"Brazing can also be used to apply coatings to parts
to reduce wear and
protect against corrosion."

Sculptors often use bronze and other metals on
steel and iron for decorative purposes as well, and this also is brazing.
See Dona Meilach's "Direct Metal Sculpture" p. 68:
"Brazing is another type of hard-soldering operation. It is used for
fusing joints and for coating surfaces."




  #29  
Old April 26th 07, 06:44 AM posted to rec.crafts.jewelry
mbstevens
external usenet poster
 
Posts: 165
Default granulation

On Thu, 26 Apr 2007 02:00:49 +0000, Abrasha wrote:

There you go again! This is NOT brazing!


http://tinyurl.com/cuqzf
....metallic bond is the main way brazing holds metals together.
Welding simply mixes the metals making them one chunk of metal.


  #30  
Old April 26th 07, 07:08 AM posted to rec.crafts.jewelry
Peter W.. Rowe,
external usenet poster
 
Posts: 355
Default granulation

On Wed, 25 Apr 2007 22:43:40 -0700, in rec.crafts.jewelry mbstevens
wrote:

On Thu, 26 Apr 2007 02:00:49 +0000, Abrasha wrote:

There you go again! This is NOT brazing!


http://tinyurl.com/cuqzf
...metallic bond is the main way brazing holds metals together.
Welding simply mixes the metals making them one chunk of metal.


Yes, though the difference between this and brazing is that the two
objects/surfaces/etc being bonded are both melted. Whether they actually mix
much depends on the type of welding. If both are the same type, and both
surfaces melt, they will solidify as one, recrystalize as one, without needing
to actually mix. If only one surface melts, as with your gold on silver
granulation (according to your analysis), then this is not brazing, because
you've not introduced a seperate filler alloy. Rather, the molten surface
diffuses into the non molten one, producing a bond. It's the same type of bond
produced by brazing, of course, but that's not really a valid label for it,
since no external bonding alloy is formed, if the gold does not melt. So then,
perhaps neither welding, nor brazing, is accurate. Rather, then fusing would be
most accurate.

However, I'd guess that when the silver melts, the gold surface in contact with
it at least slightly melts too, forming a thin layer of eutectic alloy. This is
then the same thing, metalurgically, as what happens with classic granulation by
means the the added copper. A eutectic alloy forms at the interface, giving the
bond. In normal single alloy granulation, the amount of that eutectic alloy
that can form is limited by the amount of copper and the temperature to which
it's raised. With gold on silver, though, because it's likely that the mix of
the gold alloy, with additional silver, makes a lower melting alloy, then the
potential supply of eutectic alloys is rather larger. how much forms will be
limited by the temperature, and by the melting point of the resulting mix. Now,
I don't know for sure that this will be what happens. It depends on whether the
addition of silver to the gold alloy would raise or lower the melting point of
the gold or silver. If either one is lowered, then what forms at the interface
is this new alloy, and then, the proper term, just as with classic granulation,
might be eutectic soldering, the term Littledale used, if I recall, to describe
his method of granulation using copper or other metallic salts to do the same
thing.

In jewelry use, brazing is a term seldom used. More commonly used in other
industries, where "soldering" refers to what jewelers call "soft solder", such
as lead soldering, the term brazing in industry generally applies to the same
sort of operation as we jewelers call soldering (hard soldering), and generally
implies the addition of a distinct brazing alloy, not the in situ formation of
one from parent metals.. In classic granulation, brazing/soldering might be an
appropriate term since additional external metal, ie copper from plating or from
reduced copper salts, is added to the joint resulting in a distinct third alloy
that forms the joint before dissipating into the parent metal. But in the
method described in this case, no external filler or solder or other metal is
added. The whole is simply heated until fusion takes place. Since it happens
with one or both surfaces at least slightly melted, "fusing" is likely the best
term. If it were done without heating to melting temps, (as in making mokume
billets), then it would be diffusion bonding. The term "fusing" is not
especially specific. It does not require both surfaces to be the same, or both
to actually melt. All it requires is that two surfaces or items melt together
to form a bond. One can melt, or both can melt, so long as they join in the
process.

But in the end, might I suggest that there's way too much argument going on
about the definition of the words. While words are important, much more
fundamental and important is to understand the process going on. After that,
the words are just tools to communicate, and in this case, even the words used
are not consistant between the jewelry industry and the rest of the world.

So can we just not get so worked up over which word? It's not the important
part of the content, nor worth getting angry about.

Peter


 




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