Chaser's pitch

Generally, chaser's pitch must become soft or even liquid when heated at moderate temperatures, in order to fit the object and fill all its nooks and crannies.

[1] There are many varieties of chaser's pitch available, that differ on the nature or the ingredients, physical properties (such as fusibility and hardness), or place of origin.

A blow torch as used by plumbers may also be used, although it creates a fire hazard since the pitch (and any vapors it may release when hot) are flammable.

The bowl, typically 6 to 20 cm in diameter, can be placed over a sand bag or leather ring, and tilted to whatever angle is most convenient.

[1] For deep repoussé or chasing works, the pitch is usually applied as a thick layer on top of some backing material that can accommodate larger deformations.