View of workers inspecting aluminum airframe components at the Dodge Aluminum Forge plant. Label on back: "One of many inspections of vital airframe components is pictured here at Dodge Aluminum Forge, which forges all parts of 14 ST aluminum, recognized as one of the toughest 'dural' materials now in use. This aluminum alloy requires artificial ageing -- for 12 hours at 350 degrees Fahrenheit -- after heat treating to give it maximum strength. Most other aluminum alloys depend on atmospheric ageing for toughening. From: Ruthrauff & Ryan, Inc., 7430 Second Blvd., Detroit, Michigan." Handwritten on back: "Aircraft--Bombers (Parts & assembly)."
