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
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
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.