Subsequently, the family relocated to San Luis Potosí, Mexico, where they operated a hardware business.
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.
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.