Abstract: A pyrotechnic device having a maximum explosive effect with a minimum quantity of explosive composition. The device is in the form of a polyurethane plastic foam body molded about a firecracker tube. The firecracker tube contains a small explosive composition charge therein and into which a fuse extends. The tube is sealed at each end by packing means. A polyurethane sealant coating is provided over the tube to seal any openings in the tube and any openings in any interface between the tube, the packing means and the fuse. The sealant serves as a good engaging surface to which the body portion of plastic foam will adhere when molded. When completed, the plastic foam body has a predetermined shape, such as cylindrical, generally spherical, or multifaceted.