I have made some progress on the head of the halberd. For epoxy putty, it is mostly an additive process; sculpting is done inside out. I tend to wait for one layer of putty to cure before working on top of it. Having something stable underneath to push a fresh layer of putty about is helpful in my books so this tends to be a slow process. Brown stuff sands down well, unlike green stuff, which is why the halberd is sculpted fully in brown stuff.