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Melting gold


#41

hi gerald ray bundell from southport uk, i echo your sentiments i
dont preforge my metal before milling, but i always was taught to
roll one way and aneal frequently had very few finishing problems
over forty years! and believe me i recycle customers gold more often
than new. but i also see the science behind the preforging technique.
having said my finish is still vastly superior to cast finish. but as
always the customers for most of us tend to dictate the bottom line
profit on a job. contentious i know but valid! and an extra process
when not neccessery adds time to the job.true not perfect but valid
also. i have not many custmers that have asked me to date to create a
technique perfect job for extra cost. more a job superior to mass
produced high street tat. just my take on the current thread.


#42

Hi,

Now the question would be, why not take a few minutes to follow in
the footsteps for prior masters assuming they know something you
don't and you gain the benefit even if you do not have all the
scientific explanation. 

Following the footsteps of prior masters is one thing, but I’d
prefer to not do it blindly.

The more I fall into metallurgy, the more I need to know. The
Eutectic point of custom alloys being a sore point for me at the
moment.

I like to know why things happen. When you know why things happen
you can understand why they’re done that way. If you are fortunate
you can even improve upon time honoured techniques, with efficiency
and innovation. You can also pass on why those techniques work, and
some bright spark in the future may come up with an innovation
currently unthought of.

A good example is how the Romans discovered how to harden steel
swords. There was a trade in stabbing slaves with red hot steel to
impart their essence into the swords. Who’d have thought that
sticking that same red hot sword into a barrel of olive oil would
achieve the same result :open_mouth: If they hadn’t learned why and how
hardening works, we’d probably still be stabbing people today.

If you have a technique that you use, and it works that’s fine, but
I like to know why things work. If I want to attempt to improve those
techniques, or rule out the possibility of improvement, I need the
science behind those techniques.

I get a lot of the science from books, but sometimes there are a few
links missing, and that’s what’s good about Orchid, there’s always
someone to help.

Regards Charles A.


#43
I used to have cracking issues with white gold until the
metallurgist at Stuller explained how to prevent it. 

His name is Randy Welsh (ex.344). He said heat the metal up to red
(turn off the lights so you can see) not orange and let it cool to
black, then quench.


#44
my finish is still vastly superior to cast finish. 

I’ve seen this sentiment, that castings can’t be as well finished as
constructed pieces, and frankly that’s just plain wrong. Of course
one can’t have porous, pitted castings and must know how to properly
use files and such.


#45

Although I’m in favour of forging before milling, I have to take
issue with use of the word “preclude”. I think “reduce the chance of
cracking” is more helpful - because it all depends on the alloy. I do
a lot of remodels of existing jewellery, and use a lot of bough-in
scrap too, so I encounter a very wide range of different alloys, some
of which are easy to handle, and others not, and their behaviour is
hard to predict - I’ve had some that can be forged, but not milled,
and others that cracked on forged, but went through the mill OK. One
pair of rings I made were in such a bad alloy that I would normally
scrap it and buy new, but they had to be made, so I spent 4 hours
making a pair of wedding bands, instead of 1 -2 hours - doing it
slowly and constantly annealing was the only way that I could work
with it!

Jamie Hall
primitivemethod.org


#46

Hey Richard,

I guess old habits die hard. I have been pouring ingots in metal
mol= ds for 30 years. No problems, no need to try something
different. I make a lot of my own sheet and wire, sterling, white,
yellow and red gold in 14kt and 18kt, and 22kt. 

What ever works, works :-).

I used steel moulds when I was first started the jewellery making
process, and I found them okay, but due to my impetuous nature, I
didn’t like having to wait (I guess I’m a product of my generation).

The Delft clay provided, for me, a faster, more precise, and
consistent way to do what you’ve been doing for 30 years.

Different techniques producing similar results. It’s all good :slight_smile:

Regards Charles A.


#47

Hi James,

You need to learn to read phase diagrams. This would have shown
that there are areas of ordering that occur in copper gold alloys. 

I’m learning to read phase diagrams, but even then there are issues
(like eutectic points of custom alloys… if they have a eutectic
point at all… argh!).

Here’s the scenario 62.5% Cu 37.5% Au. A 9ct deep red (I forgot to
tell the carat in my previous post), and I was told that I would
have issues with the alloy, and it would oxidise easily (the
oxidisation is something I’m after for this project, so that part’s
cool).

Straight from casting, the ingot is in an annealed state, so it
should roll, which it did, but I could feel that things weren’t
right.

I annealed the ingot, but obviously not for a sufficient amount of
time (I will be swatting up with Grimwade’s book), as when I started
to roll again, it was cracking. My mistake was assuming that 9ct gold
was 9ct gold, a mistake I wont be making again.

So I was faced with cracked metal, and the perceived time is short
for project completion. I had the extra silver and the extra gold, so
I changed the alloy mixture to a red gold instead if deep red. The
addition of the silver made a world of difference. No problems
experienced.

I was told the other day, from a supplier, how to “properly” anneal
18ct yellow gold, I am yet to find an working jeweller that anneals
to that extent ie, hold the gold at annealing temperature for 18
minutes.

Regards Charles A.


#48
You need to learn to read phase diagrams. This would have shown
that there are areas of ordering that occur in copper gold alloys.

Exactly !!!

People like to mixe all kind of metals without understanding what
they are doing. It ain’t that simple at all! That’s why they call it
metalurgy, it’s a sience. Reading and understanding phase diagrams
keeps you out of trouble. Finding an exotic new metal based on gold
or silver is pretty much covered and by much more equipment then a
forge, melting pot and a killn.

Have fun and enjoy (might be not the best way to end this
contribution joke)

Pedro


#49

Hi Richard,

I quench my nickel white golds in denatured alcohol at black heat.
Pretty much solved cracking problems. (I also don’t usually forge the
ingots cast in to steel molds, although I have in the past.)

All the usual caveats and warnings about alcohol and fire.

Take care, Andy


#50
Here's the scenario 62.5% Cu 37.5% Au. A 9ct deep red (I forgot to
tell the carat in my previous post), and I was told that I would
have issues with the alloy, and it would oxidise easily (the
oxidisation is something I'm after for this project, so that
part's cool). 

Go to Grimwade pages 60-61 he describes a phenomena called ordering.
Your alloy is ordering this makes it brittle because the random
distribution of gold and copper atoms is replaced by a structure
where the atoms fall into a regular repeating pattern. This causes
it to become considerably less ductile. At 18k this is so bad it
will literally fracture if you drop it. The area you are working in
is not as hard but still brittle.

Straight from casting, the ingot is in an annealed state, so it
should roll, which it did, but I could feel that things weren't
right. 

Nope not annealed, as cast, there is a difference. Second the slow
cooling is what allows the ordering to take place. All red golds
should be quenched rather than allowed to cool slowly.

So I was faced with cracked metal, and the perceived time is short
for project completion. I had the extra silver and the extra gold,
so I changed the alloy mixture to a red gold instead if deep red.
The addition of the silver made a world of difference. No problems
experienced. 

Yes a 4-5% silver can make a big difference and keep the ordering
from occuring.

I was told the other day, from a supplier, how to "properly"
anneal 18ct yellow gold, I am yet to find an working jeweller that
anneals to that extent ie, hold the gold at annealing temperature
for 18 minutes. 

Annealing is a time and temperature and history of work process.
Holding at a “correct” temperature for 15-30 min makes a huge
difference in some cases. But as you observe most goldsmiths don’t
do this but most manufacturers do. If you screw up a few grams to
tens of grams not so big a deal. If you screw up kilograms of
product it is a big deal so taking the time and using the right
equipment to do it right is much more critical.

James Binnion
James Binnion Metal Arts


#51

Hi Pedro,

Well I could stop experimenting, but I’m willing to do it and what’s
the harm?

Unfortunately when you’re using non-traditional elements in
experimental jewellery alloys, you’re pretty much on your own.

I’m pretty much okay with the chemistry side of the elements I’m
using, which family they belong to, what properties they "should"
bring to the alloy mixture. As with all experimentation there’s
expected results and unexpected results.

Phase diagrams are not calculated, they exist through experiments,
measurements, and observation.

My sore point is determining the eutectic point, which cannot be
calculated with any degree of accuracy, it has to be observed, and
recorded on a phase diagram.

The current process I’m going through with my experimental alloys is
this :-

  1. I make a hypothesis based on the elements used and the target
    goal.

  2. I make the alloy mixture.

  3. I send samples off for destructive testing (I make sure I get all
    the pieces back.

None of the elements I’m experimenting with have been used in
jewellery alloys, or at the very least have not been patented.

Basically I do what I can at home, the I send the samples off for
testing and evaluation.

Is it a waste of time and resources(?)… maybe… but then again I
may find something useful.

Regards Charles A.


#52

Since I’ve been working with palladium white gold, I really don’t
have any interest in working with nickel white golds again. With the
easy to pour ingots, and great rolling/drawing characteristics, it
would be a tough sell to get me to go back to nickel white gold.
Also, nickel white gold was never quite as white as I liked, and I
hate rhodium plating. Palladium white gold ( I work mostly in 18K)
is incredibly white, so it doesn’t need a rhodium plating.

I’m really surprised more metalsmiths don’t avail themselves of the
technical experts that every refining company employs. They are most
happy to chat with you about their products, and how best to roll,
anneal, solder, and any other questions you might have. Want a strong
color-match solder to use with the metal you’re buying? They’ll most
likely have a good suggestion for you. These guys really know their
stuff, as that is their job. They are often quite knowledgeable about
other products their competitors sell, as many of these tech guys
know each other.

Jay Whaley


#53
I quench my nickel white golds in denatured alcohol at black heat. 

I quench in warm pickle. Works just fine.


#54
Go to Grimwade pages 60-61 he describes a phenomena called
ordering.[snip] 

Thanks for that :slight_smile:

Nope not annealed, as cast, there is a difference. Second the slow
cooling is what allows the ordering to take place. All red golds
should be quenched rather than allowed to cool slowly. 

I should have said soft :frowning: Quenching, yep I was told that after the
fact.

Annealing is a time and temperature and history of work process.
Holding at a "correct" temperature for 15-30 min makes a huge
difference in some cases. [snip] 

This year is time critical, but next year I can devote more time to
getting things 100%, as opposed to getting things done.

Thanks James it’s always a pleasure.
Regards Charles A.


#55

Delft clay. so if I cut off a white shank, can I cast up a new one in
yellow with this delft clay? Is it good for that?

Thanks


#56

Hi Jay,

I can certainly understand and appreciate your enthusiasm for PW.
I’ve worked in both 14k & 18k in both “high” palladium and "low"
palladium. (My understanding is that the high contains more
palladium.) I use the 14k low PW from AAA metals in Portland and the
high from David H Fell in CA. They work a bit differently, the high
melts at a higher temp.

Both alloys torch weld pretty nicely. Fusing/welding a band/ ring
gives you a head start with further fabrication or simply a seam-free
band. Pretty nice. Fabrication and setting are a breeze. Casting can
be a problem and is probably best using hi heat types of catalyzed
investments.

But I don’t see them as a substitute for nickel white. (I use DHF
Winter White. I buy it as casting grain–it’s listed as a casting
alloy in the catalog–and forge, roll, fabricate with it. It’s very
white: I never rhodium.) The PW alloys don’t read as white to me.
They never have, even when my eyes were fine, appearing either a
gunmetal grey (DHF, high) or a brownish white (AAA low). But I also
wonder about long-term durability. The nickel white is quite hard and
tough while the PW seems softer and more prone to wear. Although I
don’t believe it shares the stress corrosion hat nickel alloys can
have.

I know that nickel whites are not acceptable in Europe and I have
had clients with known nickel sensitivity. I steer them to PW.

Take care, Andy


#57

More than one way to skin a cat…for sure… The nice thing about
the alcohol is that I can go straight to the mill, no problems with
pickle squeezing out. The oxides blast off too, to some degree.

Andy


#58

Hi all Orchidians,

First of all I would like to thank all of you for all the great
advices and insights on your great forum! I recently received my
degree/diploma goldsmith here in the Netherlands after four years
school, including a year abroad (Antwerp, Belgium, in my case). And
it really helped me a lot reading about your experiences, but also
your articles and videos surely helped me to succesfully finish my
school with great results : D

As you al know: due to the high goldprices and recession, business
here in Europe is a bit off. This, but also the higher crime-risk
involving the branche/business, is for a lot of my collegues reason
to stop, unfortunately… This also results in a decrease of jobs
available. I am therefor glad that I got the chance to be able to
start in a great and skilled team ( as goldsmith junior ), all part
of a renowned juweler here in The Netherlands.

As for this thread: nickle gold is not an obtion anymore here in the
Netherlands. Due to the serious allergic and health-treatening
effects, it is even forbidden by law here. There is a cheap tester
available: hasulith. Basicly its a liquid indicater which changes
colour if a piece of gold contains nickle.

But nickle as whitener works extremely well. In my humble opinion, I
think even better than palladium and silver. Therefor I don’t
exactly know what my respected collegue Jay means that palladiumgold
is ‘whiter’. Myself, I love the colour of palladiumgold. But to me
its more grayish white, a bit like platinum,…a bit… And
palladiumgold is pleasantly ductile! But again: the use or re-use of
nickle containing gold is not an option!

As for annealing: after poring the ignot and letting it simmer in
the vitrex a bit. I rinse it with water, and anneal it to cheri-like
red, let it cool to black, and cool it in alcohol or even water.

Bless,
Stephen Tjon


#59
Delft clay. so if I cut off a white shank, can I cast up a new one
in yellow with this delft clay? Is it good for that? 

Yep, it’s a casting medium. CIA


#60

Hey Andy,

You know, the color of metals we metalsmiths work with is really
limited. Unless you consider chemical patinas and enamels, the bare
metals we work with are just variations on yellow, red, and white.
And we’re not really even talking about “true” yellow, red or white,
but our limited range we work in.

I’ve never thought I was color blind, but for me, I just don’t
register any “brownish” or “grayish” tones in the “white metals” I
work in. Platinum, palladium, 18k or 14K palladium white, or silver,
it all is just white to me. Now when you put them next to each other,
as in a mokume-gane billet, you do see subtle variations in color,
and that is intended! Most jewelry I’ve seen or made using
multi-colors of metal, were made of, say, yellow gold, rose gold, and
some kind of white gold to show off the contrasting colors of the
metals. You wouldn’t normally put a 14K PD white next to platinum, or
18K PD white next to 950 PD, which would then show a side-by-side
comparison of the variations in their white color.

As you know, I work a lot with clients who I coach in making their
own wedding bands. Now I will admit that none of my past clients were
experienced metalsmiths, but I can’t remember any of them looking at
their finished( white metal) rings and commenting that they didn’t
seem “white” enough.

Much of my past involved repairs, sizing, and custom work, and
almost all of it used metals I alloyed myself. It has always been
easiest for me to use alloys that were consistent in color and
workability, so that I knew what to expect in the performance of the
metal and could make a color match if I had to do a sizing later. I
used a David Fell “Soft White” nickel alloy for years, and I used to
tell my jeweler friends how “white” it was, and how easy it was to
roll out.

However, since I have been using the 18k palladium white gold with
my clients ( Alloyed from 24K and 950 PD, NOT a pre-mixed palladium
alloy. Big difference!) I just haven’t wanted to work with the nickel
alloys again. They are just too tough to roll, compared with the 18k
PD white. I guess I’m spoiled, preferring the easy rolling
characteristics of the 18K PD.

Grayish, brownish, I just see white!

Jay Whaley