Continuous Glass Fibre Strand Drawn from a Platinum Bushing

Glass fibre for cloth is not spun like wool: hundreds of fine filaments are pulled at once from small nozzles in a hot platinum box and wound up as one strand. This is the method of Slayter and Thomas's Owens-Corning patent (US 2,234,986, 1941): an electrically heated platinum-rhodium thimble melts glass cullet, a blower freezes each filament just below its nozzle, a size is put on, and a drum pulls and winds the strand. The faster the drum, the finer the fibre. The picture: a glass fibre roving (NoiseD, Wikimedia Commons, CC BY-SA 3.0).