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Alloying silver to change its color


#1

Does anyone know anything about alloying silver to change its color?

We have 750 gold in various colors; could we have 750 silver in
yellow or red?


#2
Does anyone know anything about alloying silver to change its
color? We have 750 gold in various colors; could we have 750 silver
in yellow or red? 

Sort of. Not really red or yellow.

If you play with the copper content you can get some interesting
colour variations. You wont be able to stamp the silver though.

Regards Charles A.


#3

Bill- Yes. It’s called Gold and Copper. There are surface treatments
you can do but no alloys that I know of.

Have fun and make lots of jewelry.

Jo Haemer
timothywgreen.com


#4
Does anyone know anything about alloying silver to change its
color? We have 750 gold in various colors; could we have 750 silver
in yellow or red? 

Yellow on silver was always a fire gilding process using an amalgam
of gold and mercury.

A copper coloured silver can only be obtained by electroplating.

To get any meaningful colour change will debase the silver to the
point its not worth the bother.


#5

Hi Bill,

Well, yes, probably. But then you couldn’t sell it as silver. Most
places have a minimum silver content requirement of no less than
9/10 silver, and a deadly precise requirement of 925/1000 to call it
sterling. Depends on the rules wherever you are, but the short
answer is, “Yes, but why bother?”

There are Japanese alloys that are down in the 60/40 range with
silver, that are a sort of funny pinkish grey. (Shibuichi.) But you
normally use those because of their behavior when patinated. If you
loaded it up with copper and zinc, you’d just have a very expensive
brass.

FWIW,
Brian


#6

Hello Bill,

It is possible to alloy silver to get yellow, browns and reds with
relatively simple additions of copper and zinc. You have to only
think of the different colours of solders (brazing alloys) to
realise what is achievable. In Europe the 80% silver grade is
hallmarkable and has a pinkish/red tinge to it; as a consequence
pieces manufactured in this alloy are usually heavily silver plated.
Similarly a 50% silver 50% copper alloy has been used for
commemorative coinage (particularly by the German Mint), however it
has its surface depleted of copper to brighten it.

The main issue you will find with these lower silver content alloys
is corrosion/tarnish. Unless you use some form of surface lacquer
then you will find that the higher copper content silver alloys will
discolor or corrode at a faster rate than traditional sterling
silver alloys, particularly if you use them in a bi-metal product
with regular sterling silver as it will set up an electrochemical
cell. Similarly the silver-copper-zinc alloys which would give you
the yellows and browns also exhibit a greater rate of corrosion than
sterling silver even thought the zinc content of these alloys does
give a degree of surface passivation.

There was a US alloy manufacturer that was supplying coloured silver
alloys (non-hallmarkable) in grain form and I believe these are
still available.

Charles

Charles Allenden


#7

thank you for your clear and comprehensive responses–greatly
appreciated!

bill


#8

wondering what a 925 silver/75 gold alloy would look like and its
workability.

also, 900 silver/100 gold; 800 silver/200 gold.

just curious. thanks


#9
900 silver/100 gold; 800 silver/200 gold. 

One big problem is that you can’t legally call these alloys silver
or gold in the US because they don’t contain enough of either.


#10
One big problem is that you can't legally call these alloys silver
or gold in the US because they don't contain enough of either. 

What if you did a 925 silver, but used gold instead of copper? It
could be stamped .925 in Australia :slight_smile: CIA


#11

Some engravers mix up different alloys to create different colors
such as flesh-tone for inlay work. For a few mind-boggling examples,
check out Ron Smith’s work at the Firearm Engravers Guild of America
(FEGA) website.

http://www.ganoksin.com/gnkurl/ep80au

One piece he did was a Winchester 1873 rifle to commemorate the
history of the US from the Revolutionary War up until 1873. He
inlayed and engraved several different scenes, including a Civil War
battle scene, a portrait of Lewis and Clark and another of Lincoln
and his son Tad with both the US and the Confederate flags behind
them. All of them in full color using various alloys of silver, gold
and copper. The flags in the Lincoln portrait are especially striking
in that they both have incredibly intricate inlays within inlays;
fine silver stars, copper and silver stripes and blued steel to
finish.

Experiment, Bill. Mix up different combinations. The metal won’t be a
total loss if it comes out ugly looking, send it off to be refined
and you’ll likely get most of the value back. Sure, you might not be
able to stamp it with a quality mark, but if your art work is good
enough, that won’t matter at all. The full color portrait of Sitting
Bull on the cylinder of Ron’s Colt Dragoon doesn’t qualify to be
stamped “sterling silver” and “22K”. Do you think anybody really
cares?

You ought to see Buffalo Bill and Annie Oakley on the other sides of
the wheel. You can easily make out the differences in their skin
tones (done through the use of more or less gold, silver and copper
in each inlay) illustrating the fact that they are all of different
races. Sheesh!

Dave Phelps


#12
What if you did a 925 silver, but used gold instead of copper? It
could be stamped .925 in Australia :-) 

Yes, that would be sterling in the US too, but to what end?


#13

750 silver is an archaic french millesimal fineness: mark indicating
the 'easterling" contains . 7.50% copper and could thus be marked
as such ( what we now call sterling or . 925 silver (.999 being
fine or ‘pure silver’)…

You could add more copper 80/20 to make reticulation silver or a
japanese alloy called shibuichi which is far pinker in colour and
shows an array of colours with heat treatment. Other than looking up
recipes from ancient texts, you aren’t going to get a green silver or
blue as you would with gold recipes and common metal additions. You
can get yellows (39% and 30% silver respectively) when making bronze
and brass materials more like solders for those alloys than malleable
metals. rer


#14

A few thoughts about this subject:

  1. You could get around the hallmarking by saying this is an art
    object composed of precious metal alloys.

Then in your tag, you could put down a detailed listing for the metal
contents in each color used.

  1. I understand gold can be alloyed with aluminum to make purple.

I wonder what other colors could be made by alloying silver with
metals which are not commonly used, transition elements, or rare
earth elements.

Rare earths especially are utilized for coloring glass.

  1. I’d be interested to see what everyone else has been able to
    achieve in alloy mixes. Shibuchi sure sounds interesting.

Andrew Jonathan Fine


#15

Hi Andrew,

Well. not exactly.

1) You could get around the hallmarking by saying this is an art
object composed of precious metal alloys. 

Depending on where you are, you can’t even say ‘precious’. I know
the old UK hallmarking rules prevented you from saying anything
other than “white metal"or"yellow metal” if it wasn’t a hallmarkable
quality, or if it wasn’t entirely hallmarkable. (The early
titanium work had trouble with this: might have pure gold on it, but
since the Ti wasn’t hallmarkable, nothing was.) Don’t know how the
rules have changed recently. I’ve heard they’ve relaxed.

I believe the US rules prevent you from saying ‘precious’ unless it
is of a markable quality. You can say 10% gold if you want to, but
you can’t say ‘precious’. Unless you can pronounce it like Andy
Serkus.

2) I understand gold can be alloyed with aluminum to make purple. 

Yeah, but it’s a really nasty intermetallic. Brittle as hell, and no
way to deal with it except to set it like a stone. Look at it
cross-eyed and it crumbles.

I recall hearing that somebody’d recently had some luck with a
really exotic blue that was half-way stable, but even that wasn’t
anything like fun to work with.

Regards,
Brian.


#16
Yes, that would be sterling in the US too, but to what end? The end
would be changing the colour of the silver, whilst retaining the
.925 ;-) 

I’d never do it mind, although it would be interesting to see the
result.

Regards Charles A.


#17
I recall hearing that somebody'd recently had some luck with a
really exotic blue that was half-way stable, but even that wasn't
anything like fun to work with. 

I didn’t get an exotic blue, but I got a bronze colour with a blue
sheen (I keep notes so it’s repeatable). The problem is that the melt
point is really low, and even soldering with easy solder was risky.
Need a lot of heat control. It’s also not a carat gold, just an
experiment.

Regards Charles A