Hi Gary, you will actually get much more pronounced reticulation with
brass than silver - at least that was my experience. The process is
quite straightforward. The basic idea of reticulation is that you want
a relatively impermeable crust on the surface which will contain the
just-beginning-to-melt metal beneath the surface. As the subsurface
melt occurs the surface roils and ridges into those great textures.
Someone once told me that it is a similar process to the cooling of
the earth’s crust. Some of the other experts on Orchid will know the
technical terms and metallurgical processes better than I. Whatever,
I certainly found that brass gave me a much better reticulation than
silver or gold alloys.
Because I wanted to eventually cast to a rich heaviness in 18ct
yellow gold from my originals, I started with 2mm thick brass plate. I
cleaned the surface with a coarse scratch brush, then annealed it and
plunged it into my acid pickle, figuring that this would give me an
oxidised surface. After washing and drying, I placed it on a soldering
mat and heated it up with a large flame until the surface started to
contract and form the texture.
Experiment. I found that if I over-heated the surface it would melt
smooth again. I also found that several goes at it increased the
reticulation texture, especially if I plunged it hot into the pickle
after each reticulation. The subsequent texture cast in lovely detail.
I still use it. Kind regards, Rex from Oz