In 1927, he enrolled in a bachelor's degree program in engineering and architecture at the Escuela Nacional Preparatoria of the National Autonomous University of Mexico.For a few years, Eppens designed advertisements and posters, and starting in 1930 he worked at the Industria Cinematográfica Nacional as an artist.Between 1935 and 1951, he designed a large number of postage and revenue stamps in a modernist or Art Deco style.He also designed the small, but iconic, 1939 postal tax stamp depicting a man attacked by a giant mosquito, issued to raise funds to combat malaria.In the 1960s, he created similar glass mosaic murals for the exteriors of buildings, as well as some large metal sculptures.