Artist Dragan Bibin has developed an interesting method to create reference maquettes using gesso-saturated cotton.
He begins with an armature made from aluminum wire and tin foil, wrapped in masking tape.
This framework is coated with acrylic gesso. Then bits of dry cotton are applied to the wet surface and shaped with a small brush, adding more acrylic gesso until the cotton is saturated enough to hold the desired shape.
All the shaping is done with a small brush. The forms are built by adding layers of patches of the saturated cotton. This method is actually very fast, because you don’t have to wait for the surface to dry to build upon it.
The resulting maquette is inexpensive, lightweight, airy, very tough, and durable, since the acrylic polymers are fairly elastic. Once it is fully dry, it can later be sanded and painted with acrylic paints.
Dragan's Blog with more pictures