I took an 8″ and 2″ styrofoam ball from the floral section of my craft store and used it as an armature for a bird sculpture. I cut the 2″ ball in half with a serrated kitchen knife and hot glued it to the larger ball. Then I cut a 5mm sheet of EVA craft foam into feather shapes and hot glued them like shingles to the large foam ball. I began to trowel the concrete paper clay onto the armature with a pallet knife covering the foam.
The EVA foam was cheap and easy to cut with scissors. Being able to quickly cut and hot glue an armature shape quickly will be a very helpful technique for future creatures.