I used a floral foam on the barrel is like balsa foam ,color green or brown i get it in Michaels is very soft and you can cut, drill it very easy , and mold it with your hands ,for the cilinder i use styrofoam white then i cover it with acrilic gesso for harden it , and glue it. Glue.- I use "Hold the foam " ( micheals ) you can try with hot glue.Im going to do another with styrofoam white and cover the barrel with Ceramic Stucco Texture Gel " Liquitex I use it for made model bases " is very light ".