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Annealing 18K White Gold


#1

Dear all Orchidians,

Hi, I am a self-taught jeweller in Hong Kong who always work with
silver. Recently I need to make a hammered white gold band. So I got
a piece of 3.5 mm 18K white gold round wire (I didnt order
palladium-white, so I suppose it’s nickel-white…) and planned to
solder a plain band and hammer it afterward.

However, I just found out that I couldnt even anneal it. I went
through Oppi’s bible and other masters’ book for advices and tried
heating it up with hand torch to bright red then air-cool but it’s
still as hard as steel.

So I am desperately looking for help! What’s going wrong actually?
Was the temperature not high enough? Is it impossible to anneal 3.5mm
white gold wire with Prince 3000S hand torch? Or have I missed out
any procedure? Please kindly advice, THANKS A LOT!

Best,
Vivian


#2

You might want to try quenching in denatured alcohol. This is
particulary effective for nickel white golds.


#3
I just found out that I couldnt even anneal it. I went through
Oppi's bible and other masters' book for advices and tried heating
it up with hand torch to bright red then air-cool but it's still as
hard as steel. 

First keep in mind that some of the 18k white golds, especially the
very white alloys with higher nickle content, are pretty hard metals,
even when fully annealed. Compared to silver, or to many yellow
golds, it will always feel really hard. But you usually CAN anneal
it. With most of them, the trick is not to air cool them. Slow
cooling allows the alloy to age harden again, and the result with
some of them, is VERY hard. Anneal by heating not to a bright red.
That’s too hot. Just barely red is enough. Allow the red color to
fully disappear, and then quench. If you wish to be safest, quench in
alcohol rather than water, since some of the 18K white golds might
crack if quenched in water. (Most are OK, though) Be careful with the
alcohol, so as not to set your bench on fire with it. Quenching the
metal quickly in the alcohol, fully immersing it, won’t ignite it. If
it does somehow ignite (usually with your torch), then just calmly
put the lid on the container to put out the fire. Use a container
with a metal or glass body and lid for that reason.

And when working it, use good quality hammers and tools. With some
poor quality tools, soft steel really is too soft for some white
golds.

Peter


#4

Dear Peter,

Thanks a lot for your precious advices! You are right, I’ve double
confirmed with my supplier today that what they had sold me was
Nickle White gold with no palladium - that’s why it’s so hard.

I’ve tried your annealing instruction today, i.e. slowly heat it up
to barely red and then quench after the redness has just faded - AND
IT WORKS!

However, that only allows me to slightly alter the shape of the
wire, which is, barely changing the curve for few degrees only, and
it became steel-hard again. I then annealed it again in the same way
and gave it few strikes with a swiss-made hammer - there are only
hammering traces, but the round shape of the wire barely changed at
all.

As what I would like to make originally is to solder a plain band
with a 3.5mm round 18ct white gold wire in US size 4 1/2 and then
hammer it into a irregularly oval band up to US size 7 1/2, this
nickel-white is probably too stubborn for this task. I am planning to
refine it as scrap and get a softer alloy from other suppliers.

So, what will be the right white gold alloy to look for, as a bench
jeweller with 2 hand torches, especially if I am interested in
hammering works? Besides, will the above task be anyway impossible
for any kinds of white gold alloys? (i’ve tried it in sterling and it
works well, of course, but I have no clues on how it will be with
gold alloys…) Or, shall I simply get a seamless court-shape cast
band from Rio Grande with just 1 size smaller and slight hammer it to
give it a desired texture?

Sorry for all these clumsy questions! And once again, really
grateful to your help!

Best,
Vivian


#5

Vivian,

Could be a number of things. Have you tried this procedure. Warning
it involves alcohol and heat so be careful. heat your piece up to red
hot and then quench quickly in alcohol. This procedure has helped me
in the past with stubborn gold. Please be very careful when doing
this, Use rubbing alcohol at 70% to be safe (higher flash point),
Keep the torch well away from the alcohol while heating the piece. I
use a tall jam jar full of alcohol and leave the lid on loosely while
I heat the piece to avoid vapours (flammable). When quenching be sure
the piece can be plunged quickly till it is completely covered to
avoid producing excessive alcohol vapour at the surface. You should
see a silvery bubble of alcohol vapour form around the hot piece when
you submerge it. This vapour controls the cooling speed and provided
the piece is totally submerged, is safely re-condensed back into the
alcohol liquid. When the piece is cool enough you will hear it douse
itself. It should then be cool enough to remove and work.

Good luck
John


#6

There are several things to remember when annealing nickel white
gold.

First is to bring it up to annealing temp and keep it there for 1 to
2 minutes to allow the metal grains to regrow and the allow to
rephase. Be sure to not overheat it…draw your torch back as it
reaches temp, then quickly quench in denatured alcohol (as Drew
mentioned)…do not wait as with sterling silver in water. The
alcohol provides a controlled quenching at just the right speed to
create the structure needed.

Cheers from Don in SOFL


#7

Hi Drew and John,

Thank you very much for your advices! I will for sure try the
alcohol quenching. But I am also curious - may I know what is the
mechanical reason for quenching in alcohol instead of water?

Best,
Vivian


#8

Vivian,

when the hot metal enters the alcohol, the liquid immediately
surrounding it vaporises and forms a bubble around the metal. You can
see this as a silvery coating. It lasts for a few seconds (depending
on the size of the piece) and then disappears with an audible
quenching sound. What is happening is that initially the metal is so
hot that it instantly boils the alcohol in contact( alcohol has a
much lower boiling point than water). This vapor forms the bubble
which acts as an insulator and slows the cooling process, which in
turn allows the correct crystallization of the metal for annealing to
occur. Once the metal has cooled sufficiently, the bubble of vapor
reduces in size until the liquid alcohol can reach the metal and you
get the rapid cooling (quenching) as you would with water. Its like a
delayed reaction quenching effect. The procedure has helped me on
many occasions. Some “Scrap Gold” ay have been alloyed for casting
and can be difficult to roll or bend. This method of annealing helps
to render it more workable.

good luck
John Bowling


#9

Vivian,

Thank you very much for your advices! I will for sure try the
alcohol quenching. But I am also curious - may I know what is the
mechanical reason for quenching in alcohol instead of water? 

Quench the same piece in alcohol and water. You should be able to
see the slower cooling rate in alcohol. Same logic applies for
hardening steel in water, brine, or oil. Besides it is a very good
test of your morning coffee strength and fire reflexes.

Jeff
Demand Designs
Analog/Digital Modelling & Goldsmithing
http://www.gmavt.net/~jdemand


#10

Once again, thanks for all of your previous advices and detail
explanation!

I’ve finally tried the alcohol quenching method with the die-hard
nickel white rod. It’s true that the peeling problem is now gone.
However, the rod refused to be annealed again (even after quick
heating up to dull red and quench immediately). And I try to quench
it in water again, the annealing is then effective again (though it’s
still relatively hard)

But why? Is it becoz the rod contains only nickle and gold, but with
no copper at all?

Cheers,
Vivian


#11
However, the rod refused to be annealed again (even after quick
heating up to dull red and quench immediately). And I try to
quench it in water again, the annealing is then effective again
(though it's still relatively hard) 

This is partly facetious, but since this is ongoing - use platinum.
Just by way of POV… Most 18kt white gold is so cantankerous it
should be taken out back and thrashed… ;<} Plus there’s no reason
other than what is essentially snobbery for using it, though some
jewelers are used to it. 18kt yellow is a more golden color than
14kt. 18kt white is white, just like 14kt white is white. We’ll work
18 white to please somebody now and then, but basically it’s “If you
want something “classier” than 14kt, go platinum.” Which is a joy to
work, once you learn how (it’s quite different to work). Not helpful
to the question, I know, but it’s my own solution to it, too.

http://www.donivanandmaggiora.com


#12

In the past week I have made several rings- two cast in 18k nickel
white, and one in 950 palladium sheet. I also down sized a vintage
18kw band with 3 diamonds in it. The palladium worked rather easily.
The castings assembled and set without a problem. The vintage band
was a struggle.


#13
Most 18kt white gold is so cantankerous it should be taken out back
and thrashed... ;} Plus there's no reason other than what is
essentially snobbery for using it, though some jewelers are used to
it. 

Yup 18W is pretty hard stuff and that’s why I like it for some
applications. Like long thin prongs. Plat is kinda soft for that.
18W castings are a bear though, tend to crack when you coerce it, but
milled stock can be quite useful. A trick I found for setting 18W
prongs, which because its a hard alloy it can take a lot more force
to bend a prong…simply make the prong too long, the extra leverage
helps avoid the sudden ‘give’ that can break the prong or cock the
stone.