S18E12: Top & Bowler Hats, Solar Water Heaters, Sticky Buns, Electrostatic Speakers

Felt hat bodies are steamed, stretched over wooden forms and trimmed into top hats and bowlers. Absorbing collectors, pipes and insulated tanks are assembled into solar water-heating systems; enriched dough is rolled with a sweet filling, sliced and baked into sticky buns; and a thin charged diaphragm is suspended between perforated panels to create electrostatic speakers.