Method of making porous, fibrillose bodies from fibrils bonded together into a self-supporting structure. A mixture of fibrils and a viscous, non-newtonian, liquid vehicle including an organic hydrosorbent and water is (1) injected into a mold, (2) frozen in the mold to form a frozen precursor of the article, (3) ejected from the mold while still frozen, (4) freeze-dried, and (5) finally heated to remove the hydrosorbent and bond the particles together. The process is particularly effective for making fibrillose preforms for infiltrating with metal in the manufacture of metal matrix composites.