One year my students created a HUGE dinosaur, twenty feet long by ten feet high- no exaggeration. We used chicken wire and cardboard as the base, countless boxes of Ross (Pritt) Art Paste, and here's the trick- BROWN PAPER GROCERY BAGS. Cut off the bottoms of the bags and just use the rest. Tear them up into pieces and soak the paper bags in water overnite. Next, wring out the paper and dip into that "magic gook", as we call it. Apply to the armature. You'll only need one or two coats because the bags are so strong yet pliable.
The big problem was that we couldn't get the darn thing out of the room (a converted basement) for the art show because of the size. LOL..here's how I solved the problem...We painted huge dino footprints on the floors of the school's halls in the direction of the basement room. No one missed seeing it!