Crusauer Kupfer- und Messingfabrik

The Crusauer Kupfer- und Messingfabrik stands beside the Krusau stream in Kupfermühle, a village near Flensburg. Built around 1600 on the orders of King Christian IV of Denmark, it began as a hammer mill powered by the fast-flowing water. The site grew into the largest industrial plant in the Duchy of Schleswig by 1800, turning copper and brass into sheets and fittings for ships. Over the centuries it survived wars, changes of ownership and shifts from water to steam and electricity. The factory’s importance peaked in the mid-19th century when wooden ships needed copper sheathing to resist shipworm. By 1840 the works ran eight water wheels driving ten hammers, plus a brass foundry and five workshops. After Prussia took control in 1864 the mill imported copper from the Americas and installed coal-fired furnaces, raising quality enough to supply copper plates for more than 200 ships across Europe and the Americas. Later it produced Muntz metal, a brass alloy patented by George Fredric Muntz, which largely replaced pure copper in shipbuilding. Today three fully restored industrial halls house the Industriemuseum Kupfermühle. Visitors walk past original water turbines, rolling mills and casting pits that once turned out thin ‘ship-skin’ sheets. The museum shows how workers lived, with surviving cottages, a school and a brewery that once served the community. Outside, the Krusau’s steady flow still turns a small demonstration wheel, linking the present to the site’s 400-year history of metalworking.