Abstract A new device for thermal vapor-pressure shock explosion (TSE) was constructed and the dispersion of three kaolinites (KGa-1, KGa-2 and S-5, well and poorly crystallized kaolinites from Georgia, USA and from Makhtesh Ramon, Israel, respectively) in aqueous suspensions investigated. In the new device, the clay suspension is heated in a sealed glass ampoule at 300°C for a few minutes and the water vapor pressure increases in the cell to ≈100 atm. At this stage the ampoule is shattered in ice-cold water. This treatment stabilized suspensions of KGa-1 and S-5 kaolinites. Particle-size distribution analysis showed that, by this treatment, smaller particles were obtained. A suspension of KGa-2 was not stabilized by this treatment although particles became smaller. Suspensions of the three kaolinites peptized by sodium pyrophosphate, were compared with those obtained by TSE treatment. SEM images and XRD patterns of sedimented films showed that tactoids became thinner as a result of the TSE treatment. EDS analysis of Ti suggested that the small particles, after the TSE treatment were formed from the disaggregation of the large aggregates.