Mangum is a saintmaker/folk artist. He carves and paints saints of all types, large and small. He also creates nativities, nichos, retablos, bultos, trasteros, roperos, and other religious folk art. His work is often made from recycled materials: scrap lumber, old cloth, discarded tin, and other found objects. His work has been featured in Galeria Ortiz, located in Market Square and the Ursuline Gallery at the Southwest School of Arts and Crafts in San Antonio, as well as other Texas galleries.