Creating a PVC water gun requires a few common piping parts. These can be found at most hardware stores, such as Home Depot or Lowes. You will want a few hardware tools as well, which may also be found at the same stores.  You will want the following materials: a 6 inch piece of 1/2" PVC, a 3 inch piece of ½” PVC, a tee with a threaded side outlet, two 4 inch PVC nipples, one 2 inch PVC nipple, a threaded PVC cap, two threaded ball valves, a garden hose adapter (hose to ½” female thread), a ½” male adapter (female slip to male threaded), and a 2 liter water bottle. Think of the water gun as being made of three parts: the bottle adapter, the fill assembly, and the nozzle assembly. Drill a small hole into a PVC cap. The size of the hole you create will determine the size of the water stream that is created. The smaller the hole, the smaller the stream.  Check online for resources related to working with PVC pipe. There are many guides available for identifying, connecting, and modifying piping. Note that a larger water stream means you’ll have to fill up the bottle more often! The bottle adapter connects the water bottle to the gun mechanism. Heat the middle of the 6 inch ½” PVC pipe with a heat gun. When the plastic is softened, press the opposite openings of the pipe toward one another (like pushing an accordion closed). This will flare out the pipe, creating a small bulge in the center. Place this pipe into the bottle so that the bulge snugly fits in the bottle opening, and allow to cool.  Make sure to heat just the middle portion of the PVC pipe. Leave the ends of the pipe cool so that you can use your hands to compress the pipe. If the tube does not fit snug enough, remove the tube, reheat, and compress once again. Remove the adapter from the bottle and mark where the rim of the bottle meets the pipe, as well as where the pipe is first fully inside the bottle. Drill 2 or 3 small holes around the second line (the line where the pipe is first fully inside the bottle.) These holes allow the water to more effectively drain into the piping.  As a softer material, wood and metal drill bits both work well on PVC pipe.  On many bottles, about 1 and ¼” inches from the bottom of the pipe are where the pipe first becomes fully enclosed in the bottle. The nozzle assembly is the piping that connects the nozzle to the "trigger" of the gun. Attach the nozzle to a 4 inch nipple. Connect the nipple to a threaded ball valve. Afterwards, connect the other side of the threaded ball valve into another 4 inch nipple, and plug the entire assembly into the tee. Use Teflon tape to assemble these pieces. The fill assembly is where the hose connects to the gun in order to fill the gun with water. Connect a 3 inch PVC pipe to the female slip to male threaded adapter. Connect a 2 inch nipple to the ½” female threaded to garden hose adapter. You should now have two “parts.” Connect these two parts using a second ball threaded ball valve. The threaded joints can be connected with Teflon tape, but PVC primer and cement are needed to attach the PVC pipe to the tee and adapter. Place the bottle adapter created earlier into the remaining open tee and cement it in place. Adhere a little cement to the inside of the 2 liter bottle, and place it on top of the bottle attachment. Allow several hours for all of the cement pieces to set. Don’t cement the bottle in place until you are sure the bottle fits snugly onto the attachment. Screw a hose into the bottom of the gun and turn on the water. Make sure the bottom ball valve is open to allow water into the bottle. Once enough water has entered the bottle, close the bottom ball valve and remove the hose from the water gun. You will now have a “loaded” water gun. To fire the water gun, open the valve that is connected to the nozzle of the gun. The internal pressure of the bottle and piping will force water through the nozzle hole, produce a stream of water! Close the nozzle valve to cease firing. Keep a hose nearby for whenever you need to fill the gun back up.
++++++++++
One-sentence summary -- Purchase your materials. Build the nozzle. Create the bottle adapter. Vent the bottle adapter. Build the nozzle assembly. Build the fill assembly. Attach the bottle adapter to the bottle. Attach the water gun to a hose. Release the nozzle ball valve.


It will be really hard to stop yourself, and you'll probably end up falling down. If you lose control of your wheels, you could end up in a dangerous situation! If you're going to be in a busy area, it can't hurt to wear a helmet, elbow and wrist guards, and knee pads to keep yourself from getting bruised up.
++++++++++
One-sentence summary -- Don't heely faster than you can run. Don't heely near cars. Wear protective gear.


Because you're tuning the bottom 4 strings a full octave higher, you could easily snap the strings while tuning. An electronic tuner is generally safer than tuning by ear (unless you have perfect pitch). There are free online or mobile app tuners. However, since these rely on your computer or smart phone's internal microphone, they aren't always accurate. Clip-on or handheld chromatic tuners are generally better. In Nashville tuning, your high E and B strings are tuned exactly as they would be on a regular guitar. Go slowly, making short quarter-turns. Take care not to apply too much tension too quickly, or the string could snap. If you do snap a string, replace it with another one and continue on. There's no need to restring the whole guitar. Your next 4 strings are tuned to the same notes as a regular guitar. However, they are an octave higher than a regular guitar. As with your E and B strings, go slowly. Once you've gotten the lowest E in tune, your high E and B strings have likely slipped a little. Gently turn the knob to bring them back into tune. Hold your guitar in regular playing position, then gently pull the lowest E string away from the guitar, about halfway down the length of the guitar. Repeat the process with each of the other strings.  Take care not to pull too far – you could snap the string. Pull the string just about a thumb's thickness away from the fretboard. Tension them up a little and stretch them again. This will help them stay in tune longer. Then get them back in tune again and you're ready to start playing.
++++++++++
One-sentence summary --
Use a quality tuner to avoid snapping strings. Tune the high E and B strings to regular pitch. Raise the remaining strings an octave higher than a regular guitar. Stretch your strings gently and retune them.