To make an Airsoft grenade, you will need to following: PVC pipe, PVT, a pin, a bolt, a PVC coupling, glue, torch, wire, spring, washer, pressure switch, cloth, bungee cord, 1 inch PVC, and a nut.
Place the PVC in the PVT. Cut a strip in the pipe, about 1 3/4 inches, place a pin into the slit to make sure it fits. Drill a hole in the center of the PVT. A bolt needs to be able to fit in the hole. Cut the coupling to 1 3/4 length. Drill holes in the side. Cut grooves in it. Glue it to the 4 way coupling on the groove side. Use a torch to bend the wire. Slide the pins onto the wire. Bend and shape the pin that is formed by the wire. Insert the long bolt into the PVT. Place the spring inside one of the pipes. Screw it in, placing the screws into the holes that were drilled. Place the washer in the pressure switch. Place the 1" PVC in the pressure switch. Insert it onto the bolt. Lock it in with the nut. Put the pins in. Tie a tail to it with a bungee cord.