Non-PRO English to Portuguese Other Music contrução de instrumentos

Bom dia! Não consegui encontrar uma tradução adequada para esta palavra e se algém me pudesse ajudar, ficaria muito grata.

O contexto em que aparece é o seguinte:

"Each trombone takes 50 working hours to make because of the amount of parts involved. These rolls of sheet brass are a mixture of copper and zinc, and they make up the familiar horn end of the trombone, known as the bell. There are two parts, the spout and the *flare*, which get cut out of the brass. (...) The *flare* gets heated up and fitted onto a machine which spins at a 1,000 rpm. As it rotates, a tool is forced across it, which pushes and stretches the metal downwards over a solid mould creating the *flare* shape."

Muito obrigada,
Inês S