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Purple gold alloy formulas


#1

does anyone know the exact formula for making purple gold as
well as annealing

R.E.Rourke


#2

75% gold 25% aluminum, annealing will not do any good to soften it
as it is an ordered phase or intermetallic compound depending on
your nomenclature. For the non metallurgist that means it is a hard,
brittle, compound that behaves more like a mineral crystal then a
metal. There is no heat treatment that will render it malleable. If
you drop it it may break , it certainly will if you try to forge,
roll or otherwise try to deform it. You can cast , grind and polish
it like a stone if you have an inert atmosphere casting machine to
make it in, If not don’t even waste your time and metal as the
aluminum will oxidize away when you try to melt it and you will end
up with this black brittle material with tiny bits of purple in it
that will need a trip to the refiner to be of any further use.

Jim Binnion

James Binnion Metal Arts
Phone (360) 756-6550
Toll Free (877) 408 7287
Fax (360) 756-2160


@James_Binnion
Member of the Better Business Bureau


#3
does anyone know the exact formula for making purple gold as well
as annealing 

Au Al2 … you cant anneal it… turn back now… there is no hope…


#4

Au Al2 … you cant anneal it… turn back now… there is no hope…

We can cast it. Its a very nice purple.

Call me if you need some.
Linus
Au Enterprises, Inc
800.637.2278


#5
Au Al2 .. you cant anneal it.. turn back now.. there is no hope... 
We can cast it.  Its a very nice purple. 

Hi Linus;

Thank you again for your crucial help in making a very happy couple
with that rush-rush platinum casting you did for me. You should have
seen these kids. They came back to size the ring down a bit. So cute
you wanted to eat them. So romantic even a jaded old ex philanderer
like me was touched. He proposed to her on the beach in Hawaii with a
beatiful VS E color 1.27 carat in platinum, a simple design, his idea
that I fleshed out for him with my best craftsmanship. She was so
happy with it it was like watching a little kid with a new puppy. She
kept getting up on tip-toes, kinda twittering over it. Priceless, as
the C.C. card ad goes. He was so proud of the research he’d done on
diamonds and how he’d found this little known old world craftsman to
put it all together. Shiney new MBA in hand, delightful tender new
love, etc. I told them, “take lots of pictures”.

OK, now you folks can laugh at me, ol’ Dorian Grey of the bench,
getting all sentimental. Now you know why I do this, don’t you?
It’s a rare power to be able to add that little bit of sparkle to
somebody’s memories. Screw fame and fortune. I love the direct
contact. And I’ll have these customers and their friends as
customers for life. And I’ll always remember that adorable young
couple.

But about that purple gold. You can cast that stuff? Cool! Tell me,
how hard is it to polish it? Can you use typical abraisives like
carborundum, silicon carbide, and rouge and tripoli or is it more
like polishing carbide, needing cerium oxide or diamond or such?
I’m getting some ideas here . . .

David L. Huffman


#6

James Binnion,

ok, here’s a question relating to=A0Au A12:

a friend is a conservation librarian. She has generously offered to
let me melt what she termed a small quantity " of metal=A0in a room at
a university that shall remain nameless, in which books that carry
things such as live aspergillium and other toxin producing molds=A0are
held virtually in a vacum=A0to decontaminate particularly rare,
valuable, or otherwise important tomes and other paper ephemera for
up to six months per title, catalogue number, etc… What is yor take
on attempting to melt and pour=A0perhaps 2-3 ozs ( aside from the
obvious safety precautions/hazards/preparations) of the alloy=A0and
rolling or drawing it there,(also,=A0really quickly!). I specify that
amount of metal due to the time it would potentially take to

A) begin melting the gold=A0

B) adding the aluminum ( 600 degree melting point)=A0{ i’m wondering
if=A0the addition of=A0perhaps 60 grains of cupric chloride and 10-15
grains of ammonium chloride per oz.=A0wouldn’t help essentially
"soften" the crystals so that they pack together a bit nicer into the
ingot}

C) pouring the ingot and

D) putting away all visible traces of torch,
crucibles,chemicals,etc.before being discovered ( the ingot can sit
there /quench while the" evidence" is being packed up. I figured that
8 minutes was about the maximum i could proceed at this particular
location without risking anyone entering the room, based on the time
it would take to prepare 2-3 0zt. as described above. we could
explain that=A0any subsequent rolling/ drawing was an experiment
related to the potential aquisition of an anti-tarnishing patent…or
something like that…If you think it possible to melt a higher
quantity than mentioned in that short a time frame your estimation
would be valued…

I’d welcome your opinions on this, thanks…rer

Rebecca Rourke
Commissioned work
Classes Workshops Intensives
Precious and Semi-precious Gemstones


#7

David,

Thank you for the story. It is these moments that make up for so
much of the daily bump and grind. The trick is remembering them when
we what to do painful things to someone.

Bill Churlik
@Bill_Churlik
www.earthspeakarts.com=


#8

Hi all,

I have done some work with purple gold. I had some buttons cast by a
company in South Africa a while ago. I use normal jewellery tools to
work it. I saw it with a normal jewellers saw blade and I drill it or
file it with my standard tools. Polishing is done using normal gold
polishes and buffs. The material is slightly porous but it still
takes a high polish. Care must be taken if there are sharp edges as
they tend to chip. It sort of like working a cross between opal and
coral. Experiments.

I tried to solder purple gold using an aluminum based solder but that
was not successful. I figured that maybe the aluminum would join it
but all that happens is li ttle beads of aluminum ooze out of the
material. I made a wax model and then inlaid a piece of purple gold
into the wax. I sprued it up and cast the model into silver, as a
test. Did not work at all. The silver and the purple gold formed a
sort of eutectic solution and ate into the silver. Also, I had some
blue gold made up, but like green gold, the color has mor e to do
with the imagination than an actual strong color like purple gold. I
heated the purple gold up and the quenched it in Sulphuric acid to
see i f it would shatter,(because of its glass-like feel) but it
didn’t. I does make the color more intense, though. To see some
finished pieces, go to http://www.meevis.com/buttonpage16

Also, it’s great to hear Linus Drogs can cast purple gold. Linus
cast a 65milimetre dolphin in 18ct white gold that I had carved in
wax, and he did a first class job. I set 230 diamonds into the
dolphin and his alloy was v ery easy to set into. A picture of the
dolphin is on my home page. http://www.meevis.com

Cheers,
Hans Meevis


#9
   a friend is a conservation librarian. She has generously
offered to let me melt what she termed a small quantity "of metal
in a room at a university that shall remain nameless, in which
books that carry things such as live aspergillium and other toxin
producing molds are held virtually in a vacum to decontaminate
particularly rare, valuable, or otherwise important tomes and other
paper ephemera for up to six months per title, catalogue number,
etc.. What is yor take on attempting to melt and pour perhaps 2-3
ozs 

Rebecca,

My first reaction was “Are You… NUTS?!!” My second was to wonder
whether the librarian has ever witnessed the casting process
first-hand.

Casting is by no means free of by-products – the little things like
smoke and heat and humidity – that could destroy or seriously
damage the “particularly rare, valuable, or otherwise important
tomes and other paper ephemera” being stored in the room for their
preservation. Preservation rooms are typically kept in a very
temperature-controlled and humidity-controlled state: lighting a
torch in one of them would instantly unbalance that state and could
cause irreparable harm. There’s also the issue of the atmosphere in
the room – if it’s a “near-vacuum” your torch burn will NOT be as
you’d expect and could simply be pouring unburned acetylene gas (a
corrosive) into the room’s atmosphere; however, many of these types
of rooms have the oxygen replaced by an inert gas – you’d better be
damned sure that you know EXACTLY what’s in the room and its
atmosphere before you bring an ignition source anywhere near it!

How would you handle a flask blow-out? molten metal and investment
all over the place? (It happens to everyone, usually at the worst
possible moment – and I think this would be the dictionary
definition of “worst possible moment.”)

Now, having said that, there may well be those of you out there
acquainted with casting processes that are clean and by-product
free, which would be safe to perform in this type of environment.
If so, I’d love to learn about it! Otherwise, I’d stay well away
from it out of fear of losing your friend her job, losing her
friendship, and winding up on the losing side of a massive lawsuit.

Karen Goeller
@Karen_Goeller


#10

You will not be able to roll or draw it. The problem with making it
is not too hard to overcome if you can work in an inert atmosphere.
A glove box that can be purged of all oxygen is fairly easy to make
and it is no great trick to cast the material if you can get rid of
all the oxygen in the working environment while casting.

The purple gold is by its very nature brittle. The metal alloys you
are used to working with have a random atomic structure so there is
no defined position of where the atoms of gold, copper, silver etc
are in the crystal matrix. When you push on this random crystal
structure it will slip and slide and this allows you to hit or roll
or draw the material and change its form. Purple gold on the other
hand has a very rigidly defined geometric atomic structure there
will be a specific relationship to where an atom of aluminum is in
relation to an atom of gold. This ordered structure makes it
impossible for the crystals to deform and slip relative to each
other like a normal alloy so when you put enough stress on it to
disrupt the crystal structure it fractures rather than slipping. So
you cannot form it by way of plastic deformation like other metallic
elements and alloys.

The only way I know of to work it is to cast it into shape then
finish it with abrasive cutting and polishing techniques.

Jim

Jim Binnion

James Binnion Metal Arts
Phone (360) 756-6550
Toll Free (877) 408 7287
Fax (360) 756-2160


@James_Binnion
Member of the Better Business Bureau


#11

Hi Hans;

You make such beautiful work! Nice work on that dolphin. I was
surprised at the color of the purple gold. I see you found a number
of ways to use it without being able to solder to it.

David L. Huffman


#12

ah ha, perhaps you missed reading the statement at the begining on
the normal safety precautiions…for one thing, aluminum only requires
600 degrees to melt…butane torch will do it, as will it melt 24 kt
gold, in a small melting dish, in a room that is climate controlled,
and the area we propose to work in is shielded from the collection,
and i have a portable welders shield (a fabric like thing that can
encircle the work area which, doesn’t need to be big, i’m talking
experimenting with a couple of ounces of gold and a few grams of
aluminum into a beeswaxed ingot mold, with a bit of two relatively
innocouous chemicals added to work to soften the crystal structure,(
much like dough conditioner in bread making). it should be no big
deal…not a vacum per se, i’d expect an implosion…but my small
butane torch is protected with a flashback arrestor ( complete
overkill!) - and besides, unknown to the board , i’m betting- some of
the research librarians smoke in the building! so imagine them taking
their 4 cigarette lighters and directing the flame at a melting
dish,but with lots of extra precautions…we’re going for it…some
have said only by casting, others have said, go for it try it on a
small scale. I live and work in the middle of a very humid forest in
the southern appalachians…it’s been raining for 2 weeks and the
climate controlled room offered should prevent the sal ammoniac from
absorbing water vapor tht is abundant in my house, studio, lab,
etc…have no worries, i’m probably nuts, but am a decent
goldsmith/metalurgist, and the collection(s) will be seperate from
the space in which the melt and pour is done…the main thing i have
to dois not break the aloy once quenched…

thanks for the response…i enjoyed it


#13
    ah ha, perhaps you missed reading the statement at the
begining on the normal safety precautiions..for one thing, aluminum
only requires 600 degrees to melt..butane torch will do it, as will
it melt 24 kt gold, in a small melting dish, in a room that is
climate controlled, 

Aluminum melts at 1220 F, Gold melts at 1945 F. If you were to do
this you would melt the gold first then add the aluminum. HOWEVER
unless the room you are talking about requires you to where
breathing apparatus ( think scuba gear) while you are in it there is
oxygen present. So you will end up with a black brittle mess that
might have a few flecks of purple in it. In order to make the purple
gold you need an oxygen free melting apparatus.

Jim Binnion

James Binnion Metal Arts
Phone (360) 756-6550
Toll Free (877) 408 7287
Fax (360) 756-2160


@James_Binnion
Member of the Better Business Bureau


#14
  " etc..have no worries, i'm probably nuts, but am a decent
goldsmith/metalurgist"...... 

I think a decent “goldsmith/metallurgist” would do a bit more
research into the subject before trying some half experiment in a
place that should be left at peace. Trying to compare the process to
dough conditioner in bread making is at best laughable. You are
setting yourself up to fail, at least try something that has not been
done before. I would suggest you reread James Binnion’s post to your
topic before you ruin yourself some nice gold. If you honestly do
think that your onto something you should probably rethink your
statement above. Your room also needs to be more then climate
controlled for any chance of workable results you must to work under
a vacuum. Do some research.


#15

Just my two cents; you can weld aluminum with an oxyacetylene torch
using a borax flux. If I remember correctly, but it might require a
special flux. Thus if you use sufficient flux you should be able to
melt the aluminum and gold together without to much loss. I would
assume that when you poor it your going to run into a terrible
problem with oxidation. It seems like a waste of time and money to
try and do this without an inert atmosphere. Maybe If you dragged
along a TIG torch and made some fixture to provide an argon shield
over you ingot it would work. Then again If your using TIG and a gas
shield why leave the shop to do damage elsewhere?

. Lord knows I wasted enough time and money on half brained
ideas to have paid someone competent to do the job. So please don’t
take this as someone condemning you for what your trying to do.
Invest some more time in research and listen to the people that have
walked the path your wanting to take, they may already know where
trail leads. As I said before it just my two cents on the idea. Let
us know how it works out.

Regards,
Matt


#16
If you honestly do think that your onto something you should
probably rethink your statement above. Your room also needs to be
more then climate controlled for any chance of workable results you
must to work under a vacuum. Do some research. 

Wise Blood, a bit of internet wisdom might suggest that a useful
reply does not need to include plain old insults, as your post verges
on doing. Just my two cents…

And she does NOT need a vacuum. She needs an inert atmosphere. Vacuum
is one such, and a fine method indeed. But a glove box properly
flushed and filled with Argon, will work just as well, and is a lot
easier to achieve.

There are, to my mind, other potential problems or oddities with her
described method. Notably among these are the use of a torch to melt
rather than a furnace of some sort, since a torch introduces
combustion gasses, both unburned fuel and oxygen or air, and the
combustion products, (water and CO2) neither of which is totally
inert, though they may not be much of a problem. But any residual
oxygen in the flame WOULD be a problem.

And a butane butane fueled torch may not be hot enough to melt more
than very small portions of gold unless it’s burning butane with
compressed oxygen. butane with compressed air or ambient air might
not work so well, and if there’s ambient air there at all, as simple
torches require (but not those with flashback arrestors), then she
doesn’t have the needed inert atmosphere. and I’ve got some questions
about her flux additions. Ammonium chloride “softens” crystal
structures only by removing certain types of base metal impurities
(such as iron in particular) which can make an alloy brittle. If her
gold is already pure, then the ammonium chloride would only produce
it’s typical nice blue noxious smoke, without additional effect on
the alloy. And then there was the concerns for humidity. Hard to
figure what that was about. The only way moisture should enter into
this at all, is if moisture, such as from water vapor condensing on a
cold ingot mold from the flame (full of hot water vapor), ends up in
contact with poured metal. That could be a problem, spewing the
molten mass all over. But it’s easily avoided by the common means of
preheating the ingot mold before pouring.

One of the more interesting references to purple gold that I recall
is a low tech method of using the alloy. Solid alloy is not
prepared. Rather, an article is made from aluminum, and then gold
electroplated. This is then torch fired, gently, until the gold
dissipates into the aluminum, which happens below the melting point
of aluminum or gold. With care, the process can be halted just at
the point where the gold and aluminum have formed the purple
intermettalic compound, which actually can form in much this same
way, over time, on cold aluminum that’s been gold plated, or places
such as aluminum electric wire clamped into gold plated contacts. The
above method works because the gold electroplate is very thin, and
little actual mixing or diffusion needs to happen before enough has
taken place to form the color. Very different from actually trying to
melt the gold and aluminum together to make a solid purple gold mass.
But food for thought, nevertheless.

Peter


#17
    Just my two cents; you can weld aluminum with an oxyacetylene
torch using a borax flux. If I remember correctly, but it might
require a special flux. Thus if you use sufficient flux you should
be able to melt the aluminum and gold together without to much
loss. 

Next time you melt some metal look at the way the flux acts, it does
not form a skin over the metal it tends to collect at the edges of
the molten metal which means that the center portion is not covered
by the flux.

Also all gas torches use oxygen to burn, There is always some
residual oxygen present as the mixing and burning is never 100%
efficient so any torch melting will oxidize the alloy to some degree
and with this alloy any oxygen is too much. And the flame will
always pull some of the ambient air along into the crucible.

 I would assume that when you poor it your going to run into a
terrible problem with oxidation. It seems like a waste of time and
money to try and do this without an inert atmosphere. Maybe If you
dragged along a TIG torch and made some fixture to provide an argon
shield over you ingot it would work. Then again If your using TIG
and a gas shield why leave the shop to do damage elsewhere? 

What would you use for a crucible ? the TIG torch requires an
electrical connection with the metal being melted. Any metal you
used for a crucible would be melted along with the aluminum and gold
contaminating the alloy and again no purple gold. There is a method
for electric arc melting of titanium in a water cooled copper
crucible but this uses huge amounts of electricity to overcome the
heat losses in the crucible and is way beyond any home made setup
this is big industrial stuff.

You just cannot do this in air. As I said before a glove box filled
with argon and a handy melt electric crucible furnace will allow you
to make/cast the alloy. Glove boxes are not that tough to make look
them up on the internet like this one

Cheap Home-Made Glovebox
http://tinyurl.com/7v7tq

I have seen several made from acrylic or polycarbonate. However you
would probably want to make most of this one from sheet metal and
only have a window of plastic due to the chance of spilling molten
metal inside :slight_smile:

Jim Binnion

James Binnion Metal Arts
Phone (360) 756-6550
Toll Free (877) 408 7287
Fax (360) 756-2160


@James_Binnion
Member of the Better Business Bureau


#18

Wise Blood, a bit of internet wisdom might suggest that a useful
reply does not need to include plain old insults, as your post verges
on doing. Just my two cents…

And she does NOT need a vacuum. She needs an inert atmosphere. Vacuum
is one such, and a fine method indeed. But a glove box properly
flushed and filled with Argon, will work just as well, and is a lot
easier to achieve.

Yes, I will admit that my reply may have been a bit abrasive
however the point I am trying to make is sound. I can not visualize
her trying to sneak in an argon tank any more than a vacuum pump. I
also do not believe that the atmosphere and the melting methods are
going to be her only foreseeable problems.

I am trying to point out that fact that what is tiring to be done in
this experiment has been tried, and that there are so many flaws in
her theory that it simply will not work. The slightest bit of taking
the time to do one’s homework would point that out, and possibly
lead her onto a path that does have a higher chance to produce
something other then disappointment.

Sometimes you must yell for anyone to hear. Keep the change…


#19

Wise Blood, if you’ve been reading these postings regularly I’m
astonished at the tone of your posting:

  If you honestly do think that your onto something you should
probably rethink your statement above. Your room also needs to be
more then climate controlled for any chance of workable results
you must to work under a vacuum. Do some research. 

Peter Rowe is one whose postings are intelligent, knowlegeable, well
written and to the point.

You might use your real name when posting. Your "nom de email"
leaves you open to some obvious puns.

Hoping for a courteous orchid forum.

Kevin Patrick Kelly


#20

Hi,

I get calls for odd colors of gold all the time.

I have seen purple gold cast reasonably well on a few occasions
recently. The method used was a casting chamber that was vacuumed of
air then refilled with an inert gas- This is critical. I think it
will help any kind of casting where you need to avoid oxides. The
heat came from induction. The properties… Well suffice to say
the color was the only good thing about the casting. Everything else
was problematic-Soldering, setting even bright polishing proved
impossible at the time. The most successful examples have the purple
used a bit like intarsia or the way you might use lapis. Inlayed,
not soldered or welded.

There are rumors of a protected atmosphere laser welding method all
unconfirmed, or more to the point proprietary to those struggling at
the “bleeding edge” of design and metallurgy. I would take my hints
from how weird aluminum is anyway-It is smelted in an electrically
charged crucible to begin with. It is “Heliarc” welded in common
usage. Helium is the protective gas, an electric arc is the heat to
weld aluminum to aluminum.

Plasma discharge has been used to put 75% gold and 25% aluminum onto
a substrate. This is like the way Shick or Gillette puts platinum in
a thin strong layer onto razors. The stuff was still brittle as
heck.