The problem of making the small bowl described in.Chapter XIV (Outline Chasing, Raising) leads naturally to the problem of the nut-bowl, which is the same in principle, using the same tools and methods, but requires a larger disk of metal. It also opens up a splendid opportunity to illustrate and use a characteristic and typical method of decoration for sheet metal forms, namely, that of fluting, sometimes called shaping or modeling.
The first bowl in Fig. 86 shows the simplest and easiest form of fluting, and it will be used for the purpose of describing the process. For a nut-bowl a circular piece of 18-gage flat copper or brass is cut out from 7" to 10" in diameter. It is then "raised" to shape by the method described for the small bowl.