Written by: Daniel Postellon
Primary Source: postellon.wordpress.com
As part of ongoing experiments with expendable molds, I will be making another Tunguska sculpture. As you may know, the Tunguska event occurred about 100 years ago in Siberia.
First, I have brewed a batch of mint tea:
This is not for drinking. I will be making paper mache and pasting cardboard using wheatpaste. The recipe I have says to add peppermint oil. I don’t have any, but I do have lots of mint, so I am using freshly brewed mint tea, instead of water. One part flour to four parts mint tea, mix well and boil for 2 minutes.
That gelled quite quickly, after enough heat was applied. It looks like mint pudding. Next I need a bag of sand to use as a base. Tunguska I used a granite cobble, but the sand bag can be removed after casting. This should leave a hollow aluminum shell, with holes in it.
bag of sand
The next step is to surround the future hole with a cardboard skirt. Trapazoids work well, and they are glued to each other and to the plastic bag.
bottom cardboard layer
I put my tin can mold over the hole, and cast a “cookie” using paper mache. This was made from wheat paste and paper sstrips that had been soaking for several days.
This process is repeated until the bag of sand is covered. The paper mache is allowed to dry thoroughly.
multiple cookies where holes will be
The gaps between the paper mache cookies are bridged with cardboard, and taped. A hole is left to attach a foam sprue, made from packing foam and a toilet paper inner roll.
top layer of cardboard
The whole assembly is packed in dry sand, and the sprue is filled with molten aluminum.
cast with sprue
sculpture, ready to mount
Finally, the sculpture is mounted on a cast iron base. This base was once the base of a sump pump.