Sylphon

A sylphon is an old name for a cylindrically symmetrical metal bellows. When made of metal, the sylphon shape was formerly created by metal spinning onto a metal mandrel (model), and now by hydrostatic forming within a mold. Because the mold contains the convolutions of the bellows, the mold must be constructed in parts so that it can be disassembled when the forming process is complete. Legendary experimental physicist John Strong makes occasional use of the term sylphon in his famous book Procedures in Experimental Physics.