Being interested in experimenting with different materials, he cast his works also in iron, lead and pewter, attacking them with the blowtorch, and finally polishing their concave parts in order to accentuate their expressive drive.
After the informal period, Somaini started to give to his sculptures symbolic meanings (Portals, 1967): Organic forms were put in a continuous dialectic relationship with architectural geometric volumes; this visionary research culminated in the cycle of Carnificazioni di un’architettura (1974–1976).
Starting from the conviction that sculpture shall have a role in the requalification of the urban architectural context – opinion matured between 1958 and 1972, during informal experiences made on a big scale in Italy and in the United States – the sculptor formalized his own ideas, both at a theoretical and utopist level, in a series of project studies (Enrico Crispolti, Francesco Somaini, Urgency in the city, Mazzotta, Milan, 1972).
From the mid-1980s onward, Somaini came back again to the execution of large scale works in Italy and Japan, where the dialectics of the mark brought the sculptor to deal with positive/negative shapes, as in Europe’s Gate, Como, 1995.
In 1999, he realized a large series of works on paper that recalled in a fantastic way the myths and legends related to the Vulcan Etna, revisited also through the reading of Maria Corti's book (Catasto magico, Einaudi, 1999).
Somaini took part in some important exhibitions, as Arts and Architecture, 1900–2000 trusted by Germano Celant at Palazzo Ducale of Genoa (2004), Italian Sculpture of the XX century at the Arnaldo Pomodoro Foundation and Annicinquanta.