Long before we knew much about steel, iron bars were wrapped around a mandrel and forged together.
The body of the flute is made by winding carbon fibre around a metal mandrel , using a machine, and then impregnating it with epoxy resin.
The drill is switched on and the mandrel rotates.
Larger rings can be fabricated by forging over a mandrel .
A flat strip of ‘soft’ iron is folded in half around a mandrel to create the socket.
The core is then slipped onto a mandrel and wrapped with polyester mesh fabric and additional silicone.
The copper mandrel also helps control the welding heat by acting as a heat-sink.
While the mandrel is rotating, a layer of shrink-wrap tape is applied to the outside of the composite material.
Finally finished, Alex let her voice trail off as she pried the ring off of the mandrel .
The heat generated by the mandrel causes the two materials to briefly reach their melting temperature and combine.