How to Make a Water Bottle Launcher

Hold a PVC end cap firmly with pliers and drill a hole in the center of the cap with an electric drill and ½-inch drill bit. Clean the burs with 220-grit sandpaper. Pull the air valve through the hole with pliers until the groove in the base of the valve seats in the hole. Leave the cap on the air valve so that the threads are not damaged while pulling it through the hole.

Cut the ½-inch PVC pipe with a hack saw into three lengths: 78 inches, 18 inches and 2 inches. Clean the burs off of the cut ends of pipe with 220-grit sandpaper.

Make a mark 11 inches in on one end of the 78-inch piece of pipe with a felt tip pen around the circumference of the pipe. Light a candle and rotate the pipe 2 inches above the flame on the pen line. Grasp both ends of the pipe on either side of the mark after the plastic has softened. Push in on both sides toward the mark until a bump forms. After the plastic cools for a minute, push the 2-liter soda bottle onto the end of the pipe and make sure the bottle opening seals firmly around the bump.

Apply PVC pipe primer with the built-in applicator to all cut ends of the pipe.

Cement an end cap onto the 18-inch piece of pipe. Cement the other end of the 18-inch pipe to the end of the tee. Cement the end cap with the air valve to the 2-inch pipe. Do not get cement on the air valve. Cement the other end of the 2-inch pipe to the middle of the tee. Cement the 78-inch piece of pipe to the other end of the tee.

Glue all joints with PVC pipe cement. Coat cement on both ends of each joint with the built-in applicator. Push the joints together and give them a ¼ turn twist. Work quickly as the cement will harden in a few seconds and completely dry in a few minutes.

Cut a 2-inch piece of 1 ½-inch PVC for the trigger mechanism. Clean the burs with 220-grit sandpaper. Drill a hole near the bottom of one end of the 2-inch piece, slightly larger than the twine you are using. Run the twine through the hole and tie a double knot to keep it from slipping out. Apply layers of duct tape to the inside of the trigger until there is just enough friction to slip onto the end of the 2-liter bottle and stay there until pulled off with the length of twine.

Ready the launcher by filling the 2-liter bottle half full of water. Place the trigger over the end of the launcher, then quickly place the bottle onto the end of the launcher until the bottle opening seals on the bump in the pipe. Slide the trigger up and over the end of the bottle. Have a helper hold the launcher upright with the bottle at the top and the twine hanging down. Connect a bicycle pump to the air valve and pump up the launcher to 70 pounds per square inch. Remove the bicycle pump and when ready to launch, pull the twine to release the trigger and bottle. Be aware that you will get wet and the bottle will fall back to the ground after rising about 50 to 75 feet.