How It's Made Season 32 Episode 11 Tin Whistles, Horn Products, Formula F Race Cars ( Air Date 2019-03-17 ) Genre Documentary category. Overview "Stamped tinplate is rolled into a tapered tube, soldered, painted and fitted with a wooden mouthpiece before each whistle is tuned. Cattle horn is cut, heated, reshaped and polished into useful objects, while a lightweight steel space frame receives its engine, transmission, suspension, steering, safety equipment and removable body panels to become a Formula F race car.".