What is Sonotube ?
Sonotube is the commercial name for a paper tube used for forming concrete. It is used when builders want to make a concrete pillar. They set up this paper tube (comes in diameters from 8 inches to 56 inches and in lengths to about 18 feet or so) and pour concrete into it and let it dry. When the concrete is dry, they strip the paper tube off, and voila, instant pillar.