A typical cherry bomb contains a core of explosive composition (e. g. , flash powder or, less commonly, black powder) which is generally encapsulated inside a paper cup, which is in turn most commonly surrounded by a layer (approx. one-quarter inch thick) of sawdust infused with a mild adhesive (usually sodium silicate). An ignition fuse is inserted into a hole drilled into the hardened sawdust sphere, all the way down to reach the explosive composition. The fuse extends outside the sphere approximately one to one and a half inches. Once the fuse is ignited, it takes about three to four and a half seconds to reach the explosive composition and initiate explosion of the firework.