I love my day job! Tina, James VDK and I were fortunate enough to be invited to help build a life-sized volcano (well, it was actually about four stories high...) for a television show. The purpose of the show was ultimately to allow scientists to test various theories on volcanic activity but the fun part was having an explosive special fx team in to blow it up at the end of the experiments. We worked with a great production designer, Andy Berry, who tirelessly drove the construction forward for almost a month and a half (here is a link to another Instructable, a show we worked on with Andy where we got to build, and then blow up, a small town in WW2-era Germany).
I don't have much photos of the intermediate steps of the build (we didn't have time for photos and we were covered in mud and concrete!!) However, here is a very quick summary of the build:
Use a massive crane to stack 20' long shipping containers on each other to form a pyramid.
Chain and weld the containers together.
Using a 60' telehandler lift and build an exoskeleton of pallets, 2x4s, and other scrap wood around the containers.
Cover the wood with industrial rebar mesh.
Dip 100' rolls of burlap in tubs of watery concrete and drap it over the mesh.
On a 60' cherry picker go through and zip tie all the burlap to the rebar mesh. Very messy, don't wear your Sunday best.
Use a hopper and spray every inch of the surface with a liquid concrete/Hydrocal 50 mixture.
With a massive spray gun hose the whole thing down with black and brown and gray paints.
BLOW IT UP.
Tear it down. Go home and relax, that was a good day!
I'll post comment tags on the photos to explain the process. Enjoy! (I was going to say "don't try this at home" but actually it would be pretty hilarious if you did. If you do, please post photos!!! :)