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Blackening high karat gold


#1

Hello all,

Does anyone have any recommendations from personal experience about
which product is actually good at blackening high karat gold" I’ve
tried one product that said it would work on gold, but did a
wretched job… I know it can be done somehow, as I’ve seen blackened
gold jewelry for sale…

Grazie in advance,
Alexis Romeo


#2
Does anyone have any recommendations from personal experience
about which product is actually good at blackening high karat gold" 

For low spots use a flat black enamel paint.

Doc


#3

I too, will be watching this thread. I accidently did it in the past
with a pickle, which was contaminated with an unknown. The gold
tarnished like silver does, and had to be completely re-polished!

Judy in Kansas


#4

You might want to try the niello recipe found in Tim McCreight’s “the
complete metalsmith”. However, be aware that it contains lead.


#5
Does anyone have any recommendations from personal experience
about which product is actually good at blackening high karat gold"
I've tried one product that said it would work on gold, but did a
wretched job... I know it can be done somehow, as I've seen
blackened gold jewelry for sale... 

Those oxidizing solutions that claim to work on gold only do so
decently on up to about 14K. They require being heated, and applied
with a steel or iron tool for best color, and the result is a
somewhat metallic dark color rather than a good uniform black. They
don’t seem to work on higher karats. This is because anything that
want’s to actually oxidize the alloy is working with the portion of
the alloy that is not gold, and with high karat golds, there’s just
not enough alloy exposed for a good black, usually.

Enamel, Niello, or a resin version of enamel (like ceramit) can give
you good black color if you’re filling a recess.

If you’re just trying to color the metal surface without covering it
with a significant layer of anything, (ie you want a patina), your
options are more limited. The commercial “antiquing” products that
will give you the best blacks are essentially paint. They do work
reasonably well, especially with recessed areas.

Actually oxiding high karat gold is difficult to impossible
(depending on what you are talking about as high karat) but you can
get a black metallic looking surface with electroplating. Black
Rhodium, which gives a sort of metallic darkish gunmetal color rather
than a true black, is perhaps the most commonly used, and probably is
what you’ve seen in other products doing this. Relatively durable,
though of course it’s still just a surface finish that can be
removed. A better color, ie a deeper black, especially a matte black,
is probably a black nickel plate. These seem a bit more difficult to
get to work well, and the plating seems to be more fragile.

You also have a simple option of copper plating the surface, and
oxidizing the copper surface, same as you would with solid copper or
sterling silver. This has the disadvantage of introducing more base
metal into the surface, but you simply polish off the copper that you
don’t want blackened, again exposing the gold

And there are some higher karat alloys made that specifically are
intended to be blackened. Argen sells an 18K yellow gold that, after
fabrication etc, is heated to a low red heat, in air, and slowly
cooled. The result is a decent oxidized black color. This has the
advantage of being easy to do, or later redo, so long as you don’t
have anything in the finished piece that can’t be heated red hot.
Kinda makes black metal around your diamonds a poor prospect for
this material, but for some stuff, it’s an easy way to do it.

And there are also some high tech approaches. Class ring
manufacturers used to use the black paint on products, but in recent
years, seem to be doing it with a much more durable coating. I’m told
it’s a ceramic sort of coating, or perhaps a vapor deposition
coating. Either way (or maybe it’s both. Don’t know), that’s tough
and durable, and does the job. That way would work on virtually any
metal, even pure gold. But it doesn’t sound like the sort of process
suited to a small shop…

cheers
Peter Rowe


#6

If you need to blacken sections of high carat gold and retain the
metal appearance, then the best way is to first silver plate the gold
section you require blackened, then use standard silver blackening
chemicals to colour the silver plating. I have used this method many
times with success. Of course you can enamel or paint the surface,
but you loose the metal surface by doing this. I use Ammonium
Hydrosulphide diluted with warm water, which gives me a dark silver
grey colour.I also use a liquid available here in the UK called
Liberon Antiquing Fluid, which will blacken silver and copper. Just
make sure that the item you wish to colour is clean and completely
grease free. When I made my end of apprenticeship masterpiece I used
Ammonium Hydrosulphide to blacken sections of the crest, it looked
good and it has retained it’s colour for forty years so far. See it
here http://www.ganoksin.com/ftp/NAGbadge.jpg

Peace and good health to all
James Miller FIPG.
https://www.ganoksin.com/orchid/jmdesign.htm


#7

For recessed/protected areas I flash copper plate (old pickle +
iron) then use liver of sulfur.

http://www.gmavt.net/~jdemand


#8

Thank you for the suggestions, however, I’m still looking for more
on any liquids or plating that will blacken 18k gold. Any
more info out there.

Thanks,
Alexis Romeo
www.alexisromeo.com


#9

I believe we have used tellurium dioxide which is in some silver
blackeners. When used with gold we held it against some iron
(possibly steel) and it would turn black in the area of the metal. It
works with 14k not sure about higher karat gold.

ck
Chicago


#10

Alexis,

I'm still looking for more on any liquids or plating
that will blacken 18k gold. 

looking for some additional secret magic bullet? Good luck :-). If
you’re looking through the various high end trade magazines and
seeing blackened high karat gold, and wanting the same, it’s almost a
surity that most of what you’ve seen in such sources is the black
rhodium plating solutions I and others already pointed out to you.
Pricey stuff, but it does work, and looks good. Not jet black or
anything, but a dark metallic “antiqued” look which is sufficiently
durable in most cases. My boss has been drooling over that same look
for several years now, checking out everything from special alloys to
exotic vapor deposition high tech coatings. We ended up right back
with black rhodium. It really is the most commonly suitable solution
to the problem. We do it with a Rhodinette pen plater that I happened
to have around here, and pen plating solution we got from Rio.

Peter


#11
I'm still looking for more on any liquids or plating
that will blacken 18k gold 

Alexis you’ve been the beneficiary of perhaps 200 years of bench
wisdom from some, maybe not all, of jewelry bench masters present
and retired. I’ve been following with interest and the only
suggestion
that I haven’t seen mentioned is iodine painted on the surface. I
have not tried this myself. Harold O"Connor suggests it.

If all else fails, you might research the old alchemical texts. I’d
love to hear what you find.

KPK


#12
I believe we have used tellurium dioxide which is in some silver
blackeners. When used with gold we held it against some iron
(possibly steel) and it would turn black in the area of the metal.
It works with 14k not sure about higher karat gold. 

I think I remember doing this with Silver Black or something, not
just liver of sulphur. I heated the gold piece and applied the
chemical to the piece with a steel poker, stroking it on, and
possibly reheating the piece as I went along. But I was probably
just working with 14K; sorry!

M’lou


#13

If you are trying to blacken recessed areas, it is flat black enamel
paint that does the job. Lasts for years, even if the recessed area
is not very deep.

Richard Hart


#14

As I was re-setting up my old studio today, I found an old book
titled " Workshop Methods for Gold and Silversmiths by Christian
Schwahn (translated from German) 1960.

There are several recipes for “Colouring” gold. It followed a
section on colouring copper, which described several colors for
copper. However, the book does not say what color these recipes make
the gold turn then at one point, I got the impression, they were
"colouring" goldgold. i.e. making the gold golder.

But it wasn’t entirely clear,

In any case, I can scan & fax several pages to anyone who finds this
interesting and wants the entire text.

Taking into account that some of these old formulae might be
dangerous-

Older Proved recipes

Bright color on 18 carat gold:

    6 parts powdered saltpetre (bar) *
    4 parts powdered common salt
    3 parts alum
    4 parts hydrochloric acid
    1 part suphuric acid

Bright color on 14-carat gold:

    4 parts powdered saltpetre (bar)
    2 parts podered common salt
    2 parts alum
    2 parts hydrochloric acid
    1 part sulphuric acid

Hope this helps someone out there.

Cheers,
Carol /Austin, TX


#15
it is flat black enamel paint that does the job 

And I am wondering how you apply it? A tiny paint brush, or ?

Ivy


#16
it is flat black enamel paint that does the job And I am wondering
how you apply it? A tiny paint brush, or ? 

I use a toothpick.

Richard Hart


#17

Stuller has a product called “Silver Black” that works great on
silver and gold. It turns silver black instantly. For gold you put it
on and touch it with a bur or saw blade for a reaction that turns it
black. It’s great and does not have a foul odor.


#18

I haven’t run across a ‘real’ black blackener.

Sometimes tho when the chips($) are on the table you have to get
creative. Lady wanted essentially a gypsy style ring, all black, with
a diamond poking out the top. Enamel would not live long in the real
world. I carved an onyx dome(kind of a saddle really) with a big ol’
hole in it, bezel set 4ct diamond screwed into the 18K underbezel,
holding everything together. Seven years later the ring still lives
on. Still very black. The reason for the screw was so it could be
taken apart for resizing at some point.


#19

Thanks to everyone for the responses. Richard, Do you know if this
works on 18k gold or if the piece needs to be heated prior to
application

Thanks,
Alexis
Alexis Romeo Jewelry
www.alexisromeo.com


#20
Richard, Do you know if this Works on 18k gold or if the piece
needs to be heated prior to Application

I do not know which Richard you are responding to, if it was my
suggestion About flat black enamel, apply to cold metal. Let dry
overnight.

Richard Hart