There is nothing as simple as building a water rocket. To make an impressive and working rocket, abide by the following step by step procedure. The tools that will be required are hacksaw, scissors, pliers, and electric drill fitted with 1/2-inch bit. The materials needed for the project are 1/2-inch PVC pipe that is 10’ long, 1 1/2-inch PVC pipe that is 2’’ long, 1/2-inch PVC tee, 1/2-inch PVC end caps, PVC cement, candles, plastic cables, cotton string, duct tape, 2L soda bottles, replacement tire valve and clamp for 1 1/2-inch hosepipe.
With the help of hacksaw cut 10’ long PVC pipe into three parts measuring 78’’, 18’’ and 2’’. Use the electric drill to make a hole on the top of the PVC end cap. Take the replacement tire valve and unscrew the small cap and put it on one side. Insert the valve into the hole of the end cap and push it so that it sticks out at the top. Screw back the small cap on the valve. Pull the end of the valve with the pliers until it is firmly seated on the top of the PVC end cap.
Keep PVC end cap, 18’’ PVC pipe piece, PVC tee, and 78’’pipe piece in a straight line and connect them together with the help of PVC cement. To the leg of PVC tee attach the 2’’ pipe piece. Put a mark on the pipe assembly that is 11-inches from the open end of the assembled pipe. Use the candle to heat the pipe evenly over the mark. When the pipe softens at the mark, push it inside to create a small bulge. Hold the pipe straight until the bulge hardens. This bulge will act as a seal between the soda bottle and pipe.
Use the duct tape to put nine cable ties together. Ensure that all the cable ties lie parallel to one another. Moreover, their head should be lined up evenly and they should face the same direction. Slide the soda bottle over the pipe and seat it over the bulge. Tie the cable ties around the pipe such that the head of each tie holds the lip of the bottle tightly. Place the hose clamp over the duct tape to make sure that the cable ties securely stay in this position.
Take another soda bottle and cut its top and bottom. Flatten the bottle and drill 1 1/4-inch hole on either side. This will form the spring that will keep the trigger in position before the launch. In 2’’ long scrap PVC pipe drill a small hole and tie one end of 4-feet long string. Remove the bottle from the pipe. First slide the spring on the pipe assembly and thereafter slide the trigger. Pass the string through the holes of the spring. Use the duct tape to tie the other end of the string to the pipe assembly.
Fill about 1/3rd of the bottle with water and slide it over the pipe. Pull the string of the trigger so as to allow the bottle to rest properly on the bulge. Release the string so that the trigger holds the bottle in place. To the valve at the PVC end cap attach the bicycle pump and pump about 60 to 65 psi into the launcher. Adjust the position of the launcher and pull the string; the water rocket will blast off immediately.