For whistles, whistle rockets, bursts, coated rice hull bursts, etc.. This is classified as a powder by the manufacturer, but it is not fine enough for proper intimate mixing. No need to grind for use. For superrior mixing, dissolve in the least amount of warm water, add oxidizer (usually KClO4), burn rate catalyst (usually 1% red iron oxide), mix well and allow to dry to a thick putty for pressing or ricing through a screen. Adding 2-3% mineral oil or glycerine will plasticize and phlegmatize for pressing.