Abstract: The present invention relates to a method and apparatus for controlling the delivery of insoluble powders, such as metal powders, to a processing station, such as a rotatable drum for impact plating of the powder onto articles. The method includes providing separate supplies of water and a slurry of the metal powder. Water is delivered from the water supply through a fluid network to the rotatable drum in a pre-flushing operation for a first predetermined length of time. Upon stoppage of the pre-flush with water, the slurry is delivered to the drum through the fluid network for a second predetermined length of time sufficient to deliver a desired quantity of the powder to the drum. Upon stoppage of the slurry delivery, a post-flush with water supplied through the fluid network is undertaken for a third predetermined length of time to remove any residual slurry within the fluid network.