The basic technique of copper sculpting has not changed for hundreds of year. The shaping of the metal is done by hammering it into the desired shape. But copper is a brittle metal and if subjected to hammer force when cold, may easily crack or split. To prevent this from happening the copper is heated in a forge until it becomes malleable. Once it is soft, it can be shaped with no danger of cracking.
The heated metal is placed over specially shaped anvils and hammered into shape. The normal starting point for making small item like jugs and vases is to make a bucket shape and then, by using hammers of https://www.nahls.co.jp/ different sizes and head shapes, create the final object. Surface polishing is usually done with a smooth faced hammer, although unpolished finishes carrying a rough hammered look are also very popular.
High quality copper metal art is made out of ingots of copper rather than thin sheets of the metal. This is far more difficult but allows for greater variation in the thickness of different facets of the finished pieces – for example a jug would normally have a thicker base that the sides. An easy way of knowing how the metal art was created is to look at the edges of the piece. Thick rounded edges indicate that the art was created from an ingot – items created with sheets of copper will have the thin flat edges of the original sheet metal.