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Best Bronze for jewelry making?


#1

I would like to try working in bronze sheet. I have found a supplier
but they have a couple of different options for it. One is called
"phospher" bronze and the other is called “commercial” bronze. Can
someone tell me the difference and which is best for jewelry making?

I sent them a query but they said they know nothing about jewelry
and which would be better.

Thanks
Roberta


#2

a case of wrong supplier.

You want to talk to companies offering jewlers casting bronze alloys
or sheets…

Hoover and Strong sells bronze grain,K& S engineering in Chicago
(1-773-586-8503) specializes in non-precious alloy sheeting but they
are more for model makers, and hobby type work…but they do sell red
and yellow bronze(a.k.a-Dix-gold) sheet in many gauges-how much they
know about jewelry is a mystery to me! Cooksons in the UK, Rosenthal
in Miami,and Contenti in Rhode Island sell bronzes ( although they
may only have white metals at this point in the company’s
history…can’t recall at the moment!).

Commercial bronze is 90% copper and 10%Zinc, and you want to wear a
good respirator when working with it as the zinc fumes are way toxic
to your lungs, Red bronze-(or soft low bronze) is Manganese bronze:
95%copper and 5% manganeese…You cast them at the same temp. as
14kt,yellow (480 C),and etch with basic ferric chloride etchants
(like the radio shack 5.00 a bottle etchant solution). It depends on
which colour you want as to which bronze to select.both cast equally
well,soldering them though is another matter entirely…as the solder
you select or can find, also requires a respirator due to the
components…or if you have an electric welder (or gas assisted
welder) the soldering is immaterial…If i knew what you were doing-
which sounds more like sculpture than jewelry i may be of more
asitance… The MAIN thing about wearable bronzes are allergic
reactions are HIGH due to the copper content yielding the greening
reaction that occurs with some bodily chemistries or hair
products,cosmetics, chemical eau d’ toilettes,parfums,and colognes…
so applications such as bracelets and earraings and rings are best
plated afterwards with a protective layer of wahtever colour metal
you desire…and then you risk a piece looking plated,bleeding
through the plating and other problems that make me personally wonder
why you are attracted to working with bronze iin the first place- not
because it is not a “precious metal” jsut in dealing with the returns
and complaints that will inevitably follow making jewlery with the
alloy…

RE.Rourke


#3
I would like to try working in bronze sheet. I have found a
supplier but they have a couple of different options for it. One is
called "phospher" bronze and the other is called "commercial"
bronze. Can someone tell me the difference and which is best for
jewelry making? 

Phosphor bronze is Copper /Tin (~3-10%) with 1% or less phosphorus.
It’s tough, springy stuff. I still have a screwdriver made of the
stuff from my days of working in missile magazines and explosives
lockers. It’s essentially “tool bronze”.

“commercial” Bronze covers a bunch of alloys, most of which are
really modified brasses that have that darker “bronze look”. Several
of them have a significant lead content. It’s a casting alloy family,
primarily.

Ron Charlotte – Gainesville, FL


#4

True bronze is copper with 10-12% tin. Most commercial bronzes will
contain other metals as already said. have a word with you nearest
sculptors suppliers/art supplier as to where they get their foundry
work done and go from there. Phosphor bronze is used in machine
bearings and the like and too hard and often too brittle for
jewellery working. When bronze casting it is common to add a little P
bronze to the melt to degas the metal.

Nick


#5

Roberta, try Googling “phosphor bronze” and "commercial bronze."
Lots of data there, including comments on workability. “Commercial
bronze” seems to be a leaded brass.

Judy Bjorkman


#6

Hi Judy,

try Googling "phosphor bronze" and "commercial bronze." Lots of
data there, including comments on workability. "Commercial bronze"
seems to be a leaded brass. 

C22000 otherwise known as Commercial Bronze is a member of the
Yellow Brass series C2XXXX alloys and is a copper/zinc alloy not a
leaded brass alloy. It may potentially contain as much as.05% lead
and/or. 05% iron and still be called Commercial Bronze but its
nominal composition is 90% copper and 10% zinc. Lead and iron are
present as impurities rather than alloy components. The C3XXXX series
alloys are the Leaded Brasses and have lead added to improve
machinability. In Leaded Brass alloys the lead is present at
concentrations of 0.25% - 3.50% depending on the alloy.

If you go to the Copper Development Association website
http://copper.org you can look up all the standard and
chemical compositions of most copper alloys along with a lot of other
useful

If you go here you can look up the alloys by name and get basic
composition data.

http://tinyurl.com/33s2ca

If you go here you can get detailed data on any of the alloys but
you must know the Alloy Number which you get from the search listed
above.

http://tinyurl.com/2ofjyt

James Binnion
@James_Binnion
James Binnion Metal Arts


360-756-6550


#7

Hi Judy,

For any bronze work that involves forming, I like the nu-gold alloy
that most of the jewelry suppliers sell. I also really like CDA 655
bronze. It has a slightly more reddish tone than the nu-gold and
moves beautifully. The copper flashing (from heating) burnishes off
easily. I don’t know if you can get CDA 655 in small quantities or
not. I got it from Atlas Metal for a large flowery bronze railing
project.

If you want a small piece, get the nu-gold. If you have a chance to
get CDA 655, that would be my first choice.

Kirsten
www.kirstenskiles.com


#8

Sorry I missed the original post but I have had good results casting
with Caster’s Brass Chunks, Caster’s Bronze Chunks (white), and
Ancient Bronze from Rio Grande. All of these can be melted in my
electric melting furace.

When I worked at The Johnson Atelier (art foundry) we used Manganese
Bronze, but I can’t be more specific than that.

I really like the brass chunks and ancient bronze for casting, and I
solder with high-copper wire solder to attach pin backs. Warning: the
solder is silver in color. Also there is a blue/black patina that
works well with the white bronze.

Peace, Dave


#9

Hi Roberta,

I have looked into bronzes quite a bit, and it is amazing how many
alloys there are! As far as I can tell, “true” bronze is tin with
copper. It is rare to find this alloy, though. Most of the metals
called bronzes are actually brasses, and are primarily copper with
zinc. Commercial bronze is 90% copper, and 10% zinc—it’s one of my
favorites to work with.

There seem to be at least a hundred different bronze and brass
alloys, developed for different properties, and so, they are often
confused or mistaken for each other. Technically, brasses are copper
alloyed with zinc; bronzes are copper with tin, and sometimes other
alloys. Unfortunately, the names used for alloys don’t always
recognize these technicalities. For instance, Nugold, Rich Low Brass,
Red Brass, Merlin’s Gold, Jeweler’s Bronze, Commercial Bronze, 220
alloy, 230 alloy — all these names may be used to refer to
copper/zinc alloys whose composition ranges from 85 to 90% copper and
15 to 10% zinc. These alloys are all nice to work with.

By the way, they work similarly to sterling silver, so they can be
better to use than copper when learning to form, if the ultimate goal
is to work sterling silver. I like to use these alloys when teaching
forging or shell forming (anticlastic and synclastic forming).

Cynthia Eid
http://www.cynthiaeid.com


#10

I am not sure what properties are desired for bronze in jewelry
making, but as someone who cast 90% of everything, but too long
inactive, I would consider using shibuichi which is 50% silver and
50% copper. Its color would be bronze/old copper when patinated. With
the right chemical patina it may have several colors. I did not have
good luck with “Baldwin’s Patina” from REACTIVE METALS, are they
still in business? Mine seemed not to work, and directions that if it
were weak they said add copper-something-sulphate or such which if I
had to begin with, I would not have bought their patina. It is very
castable and should be rather good to work, though solder could be a
problem. I don’t know if higher silver content would lower or raise
the temperature to make a solder, but it would be easy to find out. I
did one project casting shakudo and was very pleased. I had a great
shiny black patina on the piece and then decided to redo it, a
frequent mistake I have of seeking perfection…I used 10% 24k. I
would very much like to do more mixed metal pieces and have several
things that would work out rather well…if i do the work…

Jay


#11

Has anyone played with aluminum bronze?

I’m curious whether it is more resistant to skin contact corrosion
than regular bronzes, say when used for a ring.

954 Aluminum Bronze
Manganese (Mn)0.5
Copper (Cu)83
Iron (Fe) 3-5
Aluminum (Al) 10-11.5

Nick


#12
Has anyone played with aluminum bronze? 

I have worked with very little personally- used quite a bit
industrially.

It is hard and tough -excellent in marine use. A bit hard to machine
relative to brass. Difficult to braze ( high temp silver solder) due
to the aluminum oxides. Brazing requires a very strong flux–
Superior 625 Not the friendlyest lots of floride.I would suggest
instead Everdure silicon bronze. see

http://sales.atlasmetal.com

jesse


#13

Woa Jay: Quite a few assertions, either direct or implied in your
note that are simply not true. But first I’ll weigh in on my favorite
bronzes, there are several. I’m not going to include the precious
metal copper alloys such as the shibuichis or shakudo alloys because
they are in a class by themselves in terms of patina and cost.

The first alloy really worth looking at is the classic 90 Cu/10 Sn
bronze. this is the bronze of the ancient world independently
developed in SE Asia and the Andean highlands. It can be worked hot
and cold and is quite red. This material casts well and is good to
machine. There is a modern version called phosphor bronze but it is
hot short and very hard, not nearly as good to work, Very good to
patina

A second alloy is called commercial bronze, 90 Cu 10 Zn, also quite
red, OK for casting, not quite as hard and workable both hot and
cold. It is not quite as hard as classic bronze, but is softer to
work when cold. It is available in sheet form. Fair on patina.

The modern standard is silicon bronze, usually the “Everdure” alloy.
Quite red, workable both hot and cold, casts very well. Quite hard
and work hardens rapidly, does not machine very well. Can be
patinated to a clear brown but exotic coloration is not easy.

There are a host of others, many contain lead, which I don’t
recommend using.

Back to patina. Yes, Reactive Metals is in business and ready to
take your order. They carry two patinas for use on bronzes and the
japanese alloys. One is a boiling (acutally simmering) patina called
Rokusho and it does include some copper sulphate and this is the
classic japanese patina. The other is called “Baldwin’s Patina”
(named after the inventor) and is is used cold for coloring copper
alloys. It has never been recommended to use copper sulphate with it.

Regarding the 50Ag - 50 Cu shibuichi: This alloy is quite white and
does not patina will with either Rokusho or Baldwin’s Patina. Any
shibuichi alloy with more than about 35% silver is pretty grey or
white. The artist I know who has really done some superb work with
the high silver shibuichis is Jim Kelso and he used them as light
colors. Shibuichis with with 25% or less silver can produce some very
interesting colors. The best selling one (by far) is 15% silver and
colors to a whole range including my favorite, a dark olive green.
Shakudo is great stuff, though very soft, and has a unique purple
black patina, which will develop simply by handling.

Bronzes are great to work with, though with their own difficulties.
Have fun experimenting.

Phillip Baldwin