I got an email pointing at an interesting site about sculpting metal by a method analogous to fast-prototyping-in-plastic machines, but in stainless steel + bronze. See link to exone and description in the second half of
Briefly, the bathsheba page says, "work up the design using CAD software", then at exone "the design is laid down, one layer at a time, in stainless-steel powder held in place by a laser-activated binder", "the whole model is built up," "extra powder is shaken off, the piece goes into an oven, where heat drives off the binder and fuses the steel powder", producing a "porous steel part that's about
60% dense", then the amazing part: "the stems are dipped in a crucible of molten bronze, and capillary action causes the bronze to wick throughout the piece" and "the end result is a composite metal that's fully dense, with properties intermediate between steel and bronze. It can take a polish or a patina, developing either rust (on the steel) or verdigris (on the bronze)".-jiw