Kinetic energy release distributions (KERDS') were obtained experimentally for unimolecular decomposition of small carbon ion clusters C(n)+, n = 10-13 and 18, made by dissociative ionization from perchloro conjugated hydrocarbons. A model-free approach due to Klots, based on the application of thermal kinetics to small systems, allowed the extraction of binding energies for these clusters. The results were found to be in very good agreement with literature values for collisionally activated dissociation (CAD) threshold energies. The ion C-11+ demonstrates a particularly high binding energy in agreement with its magic character in C(n)+ mass spectra, while C-13+ has a relatively low binding energy, reflected in its low abundance in such spectra.