A new and low cost method for producing single wall nanotubes and other allotropic forms of carbon. The method uses a high electric current and 127 VAC or 220 VAC power supplies to sublimation of a solid precursor, which material can be made of graphite. The solid precursor is connected to metallic electrodes, so that an intense electric current cross the contacts to pulverize the graphite under high temperature. The carbon materials are deposited in the wall of the reactor as well as in the electrodes, in an atmospheric pressure. The obtained material is purified in acids and, then, the carbon nanotubes are separated. In general, the synthesis is characterized by the absence of a metal catalyst, the employ of a short circuit current with an agent to produce carbon materials, the low pressure into reaction, and the assembly of the apparatus involving a low voltage of operation.