Vulcanized fiber tube is manufactured by winding zinc chloride treated paper on making mandrel to the predetermined wall thickness.  They are then going through puring, drying, rolling, grinding, and sanding processes to get desired inside and outside diameters. 
Vulcanized fiber tube has a density around 1.40 g/cm3.  It has good physical properties,    mechanical properties, dielectric strength, arc resistance, and arc-quenching characteristics.  Because of its excellent machinability, vulcanized fiber tube can be sanded, knurled, spirally cut, threaded, lathed, and easily fabricated to various products.  The major applications of vulcanized fiber tubes are fuse cartridges, high voltage cutout fuse liners, lightning arresters, grommets, insulators, and bushings