A series of low-toxicity gelcasting systems has been developed, The re
agents used in these systems have very low acute toxicity. The new sys
tems perform at least as well as, and in some cases better than, the o
riginal acrylamide-based system, The development of these systems is d
escribed herein, including the search for new gel compositions, the st
udy of suspensions made with the new gel precursor solutions, and pyro
lysis of the dried gels and gelcast parts, Applications of the new gel
casting systems include complex silicon nitride parts, large-diameter
rings, rapid prototyping by green machining, and metal-powder gel cast
ing.