How It's Made Season 7 Episode 11 Halogen Bulbs, Cellulose Insulation, Aluminum Ladders, Bamboo Fly Rods ( Air Date 2006-11-14 ) Genre Documentary category. Overview "Quartz envelopes, filaments and halogen gas are combined into light bulbs, recycled paper is treated and processed into cellulose insulation, aluminum rails and rungs are assembled into ladders, and carefully selected bamboo strips are joined and finished into fly-fishing rods.".