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[Source] Granulation beads in Platinum


#1

Hi

A client asked me this question

Where to buy granulation beads in Platinum?

Thanks
David Geller


#2
Where to buy granulation beads in Platinum? 

I do not think it is possible. Granulation based on principal of
creating solder in place so to speak. Copper oxide is reduced to
metallic copper which in contact with gold forms a solder, which
attaches granules to the surface. No such reaction is possible with
platinum.

Leonid Surpin
www.studioarete.com


#3
I do not think it is possible. Granulation based on principal of
creating solder in place so to speak. Copper oxide is reduced to
metallic copper which in contact with gold forms a solder, which
attaches granules to the surface. No such reaction is possible
with platinum. 

[] Copper and platinum are soluble in each other and there is no
reason that you cannot do a similar diffusion bond by coating the
interface with copper or a copper salt that would reduce to copper in
the firing process. If you would bother to look at a phase diagram of
copper-platinum you would see that there is no reason why it should
not work.

Jim

James Binnion
James Binnion Metal Arts


#4
I do not think it is possible. Granulation based on principal of
creating solder in place so to speak. Copper oxide is reduced to
metallic copper which in contact with gold forms a solder, which
attaches granules to the surface. No such reaction is possible
with platinum. 

Perhaps, in terms of granulating with the exact same method used with
gold. But consider the original Littledale paper on the subject. He
didn’t limit his method to the use of just copper oxides or salts. He
not only used a variety of other oxides and salts but made it clear
that the main thrust of the process was the forming of the lower
melting alloy (solder) at the surface interface between grain and
substrate, no matter what the exact oxide or salt or method used
would be. Now, copper plating your platinum grains, or otherwise
using copper as the alloying agent might not work well with platinum
(though I’m not sure of that either, since copper is sometimes used
as the alloying agent in platinum, especially in europe and
sometimes japan, I think), but that doesn’t mean one couldn’t devise
some other method of getting platinum to granulate. For example. How
about gold plating the platinum grains? Or palladium plating them? Or
some other metal that can alloy with platinum to form some semblance
of a decent bond. Or, one might wish the grains for attaching to
gold, rather than another piece of platinum, and one might use them
in other methods than strictly speaking, granulation. Such as
flooding a surface with a thin layer of solder appropriate to the
surface, laying grains on, and remelting the solder. Not granulation,
but a method often used in europe prior to the rediscovery of the
real way it is done, when jewelers of that period attempted to
duplicate the effect… So on that level, asking for a source of
grains isn’t tilting at windmills. It can be done somehow, I’m sure.

I normally prefer, aesthetically, the idea of someone who’s doing
granulation making their own grains, since at some level, it seems
to somewhat cheapen the effect for me to use purchased grains (just
makes it too darn easy… Like seeing nice work done with Mokume
gane, only to realize that the mokume part was already purchased,
pattern already there, and just used as such by someone who couldn’t
actually make a piece of mokume. Yeah, that’s elitism or some
possibly misguided purism, but there it is. And I know I’ll get
flack for it. I mean, I have no argument with buying ready made sheet
metal, so where’s the difference. Maybe it’s just that when I first
learned to granulate, you couldn’t buy the grains. All the good
granulation work one saw, one knew the maker had figured out that
part too. Now, it’s never certain, and somehow granulation work
doesn’t seem as precious as it once did. Less work, less research
implied. Just some precise work going through well documented
procedures now…

Thus some misgivings, normally, about just buying the grains. But
platinum is kind of a special situation there. The usual methods of
making granulation grains in any sort of quantity usually need
charcoal, either powder/ granulated when making a lot of them in a
furnace, or at least a charcoal block, etc. with jump rings and a
torch… With platinum, one’s surface options are more limited, and
my observations of making little platinum grains on normal
platinum-safe ceramics, suggest that getting really good round grains
is difficult. They tend to have a flat on the bottom… And making
any decent quantity might be technically out of bounds for many
people’s facilities. So yes, where to buy them would be useful info.
Unfortunately, the difficulties and costs of making them oneself
might be transferred as well, to finding a commercial source. I don’t
happen to know one, nor have I heard of one…

But it would be interesting to know, if they’re out there.

Peter


#5
Copper and platinum are soluble in each other and there is no
reason that you cannot do a similar diffusion bond by coating the
interface with copper or a copper salt that would reduce to copper
in the firing process. If you would bother to look at a phase
diagram of copper-platinum you would see that there is no reason
why it should not work. 

If the only object is to attach the granules, glue will work as
well. I was responding having jewellery in mind.

Leonid Surpin
www.studioarete.com


#6
Copper and platinum are soluble in each other and there is no
reason that you cannot do a similar diffusion bond by coating the
interface with copper or a copper salt that would reduce to copper
in the firing process. 

The main question I’d wonder about would be whether you’d get a
decently strong bond, or whether it would turn out too brittle.
Reducing atmospheres and platinum alloys sometimes don’t mix as well
as one would like, what with carbon/silica contamination issues.
Careful control of the conditions no doubt could take care of that,
but it might be a little trickier to achieve than with gold or
silver. Don’t know this, of course, but it would be something to look
out for.

Peter


#7
The main question I'd wonder about would be whether you'd get a
decently strong bond, or whether it would turn out too brittle.
Reducing atmospheres and platinum alloys sometimes don't mix as
well as one would like, what with carbon/silica contamination
issues. Careful control of the conditions no doubt could take care
of that, but it might be a little trickier to achieve than with
gold or silver. Don't know this, of course, but it would be
something to look out for. 

Immersion copper plating and flux would most likely work however a
multilayer plating with copper then silver on the granules will
certainly do the job.

James Binnion


#8

What about pulse welding to attach the granules? If it’s to decorate
a piece this would work, I don’t know if you could build an entire
piece out granules this way, but it might be possible with a steady
hand and good current/pulse control.

Cheers, Thomas Janstrom.
Little Gems.
http://tjlittlegems.com


#9
If the only object is to attach the granules, glue will work as
well. I was responding having jewellery in mind. 

I should let JIm respond, but sorry, can’t resist.

Leonid, you’re missing the point here. As Jim points out, copper or
copper salts used in exactly the same way in which they are used in
granulation work on gold, would behave the same with platinum.

You said:

I do not think it is possible. Granulation based on principal of
creating solder in place so to speak. Copper oxide is reduced to
metallic copper which in contact with gold forms a solder, which
attaches granules to the surface. No such reaction is possible
with platinum. 

As Jim says, copper and platinum do form an alloy that melts lower
than the platinum itself. Thus, copper oxides or other salts (or just
plated copper as it’s often done now), could create the needed
"solder" at the interface between grains and substrate.

If there are problems with granulating platinum, and there may be
practical difficulties to overcome, they would not be because “no
such reaction is possible”. Because the basic reaction is indeed very
possible.

In fact, any good platinum worker knows full well that key to good
platinum work is avoiding contamination of the platinum with gold or
silver bits, like bench filings or the like, which if left on the
platinum when it’s heated to soldering temps, alloys with the
platinum and quickly sinks in, creating sometimes a deep scar. That
effect, right there, is exactly the same basic mechanism that’s
required for granulation, except that with granulation, it’s
controlled so it does something one wants, rather than causing
damage

Peter


#10
What about pulse welding to attach the granules? If it's to
decorate a piece this would work, I don't know if you could build
an entire piece out granules this way, but it might be possible
with a steady hand and good current/pulse control. 

This is done using a Tack welder. I had an ABI Tack II with a vacuum
pickup attachment that would allow precise placement of the granules
and act as the electrode when you fired the welder. I used it to
place solder balls but I saw Steece Hermanson demonstrate Platinum
granulation with this technique at a trade show.

Here is an article on his technique
http://tinyurl.com/d6v2pg

James Binnion
James Binnion Metal Arts