The adhesivity of fresh coal fly ashes from two Australian power stations on Dralon‐T monofilaments has been experimentally analysed. It was found that one of the dusts was more adhesive to the fiber and its particles were also more strongly electrostatically charged. These obervations explain the reported large differences in the pressure loss across the fabric filters at the two stations. By precharging the particles, the technique can also be utilized in determining the adhesivity of fly ashes which carry relatively small natural electrostatic charging.