With a renewed accessibility to expansive machine shops at Sac State, Walburg was able to return to the investigation of monumental forms. In 1969, at least partially inspired by another trip to Chicago where he saw the monumental Picasso Cor-ten sculpture in the Civic Center (now Daley) Plaza, Walburg created the Cor-ten piece Loops IV. Walburg complemented the construction of his monumental sculptures with a series of sketches and watercolors, working either from maquettes of the sculptures or from projected slides of the full-scale pieces themselves.
An early apex of his career came in 1969 when he was invited to exhibit work at the world exposition in Osaka, Japan: Expo ’70. Along with renowned fellow artists Sam Francis, Isamu Noguchi, Kenneth Noland, and David Smith, Walburg traveled to Japan for the installation of his 25-foot high welded steel Column (1967). His long-time interest in eastern cultures was heightened by this visit, and it remained a keen influence on his work.
By the mid-1970s, Walburg was simultaneously creating new portal/arch maquettes—those that would evolve into the famed Indo Arch. Generally more constructivist and less metaphorically figurative than some of the recently completed Cor-ten sculptures, these more human-scaled works combined copper, brass, and bronze components into complex signature pieces.
Walburg worked on the numerous pieces in the radiant Opuntia series (1976-77), as well as works such as Reach (1976), Frame/Arc II (1977), and Kali (1975) at the same time that he was working on the Indo Arch, and in the same studio space. This was possible in large part due to the confidence he had in his primary studio assistant, Urban-O Bernardo. Bernardo had been one of Walburg’s sculpture students; Walburg credits Bernardo with being a significant influence on his “making as well as looking” in the twenty years they worked together as friends and co-workers. With Bernardo’s talents backing him up, rather than becoming confused with physically maintaining separation between the different works or becoming mentally inundated with the density of his undertaking, Walburg was able to take advantage of the critical mass of diverse sculptural components, responding on a myriad of levels, as needed, to his assistant fabricators, to the progress of each of the pieces, and to his own conceptualizations of their aesthetic development.
In the last twenty years Walburg has laid the groundwork for the larger metal sculptures by prefacing his work with preliminary studies in cardboard or paper, taking advantage of their shared property: the inability to be bent two different ways at the same time. Once he is satisfied, he can dismantle the glued cardboard pieces and use them as patterns to cut out the sheet metal.
Although most of his work is nominally abstract, Walburg has imbued almost all of the pieces with distinct narrative or metaphorical qualities. Originally influenced by teachers Bob Arneson and Bill Wiley, he built on their use of storylines as he learned about sculptors such as H.C. Westermann. More and more curious about other approaches to shape and form, he also began to explore Islamic and Hindu architecture through photographs and books. This played into his interest in figuration, an outgrowth, he says, of his interest in the female figure and working those forms into his sculpture. He has always thought of himself as a “touchy-feely” person, he admits, and he links all of his larger pieces—even the loop pieces—to the figure.