I guess nichrome wire wound around a ceramic core, then coated with (maybe?) epoxy. my biggest question: I assumed the resistance wire was originally UNcoated, bare wire, wrapped with each turn touching the next.
BUT
if it IS bare wire, then the makers either must keep each turn from touching the next turn over (with a very small clearance), *OR* the wire is coated -prior- to the winding process. otherwise, the 'resistance per turn' wouldn't be controllable - right? I mean like if one turn, near the middle of a wirewound resistor, was 'shorted' to the next winding mid-turn...
like in these things:
thanks for info, guys :-)
bubba here is kind of contemplating making a rheostat...this recipe calls for a 6 ohm, 11.1 amp type (see bottom right of page 2)
of course, i have this ol' powerstat, but it's a 5 amp model