Introduction: PVC Potato Shooter
Runner Up in the
PVC Contest 2017
This is an awesome PVC potato shooter which is powered on isopropyl alcohol. The cool thing about this type of alcohol cannon is you can get 40-50 shots without refueling. This is because integrated fuel sponges inside the combustion chamber are constantly adding more alcohol vapor. All that needs to be done between shots is add 6-10 pumps of air into the combustion chamber and your are ready to fire again. This design of fuel cells and air injection is inspired by a marshmallow cannon from the YouTube channel Sonic Dads.
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- 5ft 3/4'' PVC
- 5ft 1 1/4'' PVC
- 1 1/4'' x 3/4'' Bushing X 3
- 1 1/4'' Coupling X 5
- 1 1/4'' Tee X 3
- 1 1/4'' Slip to threaded Pipe Adapter
- 1 1/4'' Elbow
- 1 1/4' x 1'' Threaded Bushing
- 1 1/4'' Threaded Plug
- 1'' Threaded Plug
- 1'' x 3/4'' Bushing X 2
- Blue Dollar Tree Ball Pump
- Dollar Tree Lighter
- Tactical Rail Mounts
- Inexpensive Scope
- Spray Paint colors of your choice (I used Desert Tan and Black)
- Cheap kitchen sponge
- Thin steel rod (I used a gas welding rod)
Step 1: Making a Plug
First we need a plug which will separate the combustion chamber from the stock. To do this I started by putting several layers of gorilla tape on the end of a 3'' piece of 1 1/4'' PVC, Then I filled the plug with about 3/4'' of hot glue. Then using and exacto knife I cut around the edges of the tape leaving a clean plug.
Step 2: Construct the Main Body
To construct the main body start by gluing a 1 1/4'' x 3/4'' bushing into a 1 1/4'' coupling. Then glue a 1.5'' piece of 1 1/4'' PVC to the opposite end of the coupling. Next glue your second coupling to the first coupling. Continue this pattern of gluing a 1.5'' piece of PVC between each fitting with the next two tees and finally the threaded adapter. Next glue a 3'' piece of 1 1/4'' PVC into the tee closest to the threaded adapter followed by the 90 degree elbow. Finally glue a 12'' piece of 1 1/4'' PVC to that elbow ending with a tee. Make sure to refer to the photos to ensure your gun body is coming together correctly.
An important thing to pay attention to when gluing the body together is ensuring that your elbows and tees are aligned with each other. If they are not all on the same axis you will end up with a crooked gun. To make sure they are all aligned I like to press them flush with a hard flat surface like a concrete floor right after gluing.
At this time It would be a good idea for you to cut a 2 foot length of 3/4'' PVC for your barrel but DO NOT GLUE IT INTO THE GUN, it is intended to be removable for reloading.
Step 3: Making a Hole for the Trigger
To make a spot for the piezo igniter trigger to go. I heated up an old screw with a propane torch and used that to melt a hole. Then I cleaned off the melted PVC with a knife and some sand paper.
Step 4: Extracting the Peizo Igniter From a Lighter
I have found that dollar tree barbecue igniters are a very cheap and effective source for spark igniters. All it takes to get the peizo igniter out is to snap open the outer casing and pull the piezo unit along with its corrosponding wires.
Step 5: Installing the Piezo Igniter Trigger
To install the trigger, put the spark igniter into the hole we make previously and hot glue it in place. Then drill two very small holes about 1/4 in apart on the combustion chamber directly above were you glued the trigger. At this point you need to trim and strip the wires so that they stick through the holes into the combustion chamber about 1/4 in. Finally hot glue the entire assembly in place making sure not to hot glue the moving parts of the trigger.
Step 6: Making the Heat Sink
To make the heat sink you will need to print this template. Cut out the template and tape it onto a piece of 1 1/4'' PVC, then cut out the 8'' piece as shown by the template. Use the cross hairs inside the circles as reference points to drill the holes. In the end you will want 1/2'' holes, but it is a good idea to start with a small pilot hole and work your way up. It often can be difficult to drill 1/2'' holes strait from the get-go.
Once you have all the holes up to 1/2'' in diameter you will need clean up the holes with some sand paper and an exacto knife. This will get rid of any rough parts or attached shavings.
Step 7: Attaching the Heat Sink to the Barrel
To attach the heat sink to the barrel first you will need to modify 2 1'' x 3/4'' bushings by carving out the stopper which prevents the pipe from going more than 1/2'' into the bushing. This enables the bushing to slide along pipe anywhere you want. To figure out where the bushings need to get glued, form fit the heat sink and the bushings together leaving a 1/2'' nub on the short end so the barrel can get pushed in the main body. Mark where the bushings need to go then glue everything into place.
Step 8: Adding the Air Injection System
To add the ball pump air injection system start by marking a cross hair centered where the ball pump naturally fits into the body of the rifle. (see pictures) Then drill out a 1/4'' hole where you marked.
Next you will need to hot glue a piece of vinyl tubing to the output of the pump. Measure the tubing so that it reaches 2'' away from the threaded adapter. Thread the tubing up through the hole you drilled, then finally hot glue the pump to the body using a liberal amount of glue so that it will not fall off. Make sure you also seal where the pump touches the hole with hot glue as well so that no air can escape.
Step 9: Making the Suppressor
For the suppressor you will need 3- 1 1/4'' couplings and 2- 1 1/4'' x 3/4'' bushings. The bushings need to modified so that they can slide over 3/4'' pipe further the half inch or so. To do this I use a sharp knife to carve out the stopper then some sand paper to smooth the surface.
Next you need to glue together the 3 couplings with 2- 1.5'' pieces of 1 1/4'' PVC. This will make up the outer casing of the suppressor.
The core will be made out of a 6 1/4'' length of 3/4'' PVC which has a bunch of small holes drill in it. Except for the ends where we will be gluing. (see pictures) After drilling it is important that you sand the inside of the PVC to make sure it is as smooth as possible so it does not interfere with the projectile.
When gluing the core and bushings in, you want the core to be flush with the bushing on one end and recessed in the other. This will enable you to attach the suppressor to the barrel by pushing the barrel into the side where the suppressor's core is recessed.
Step 10: Making the Stock
To make the stock you are going to need some way to heat up the PVC so that it becomes malleable. I used a propane torch, but you could use a heat gun or even a bed of hot coals. Heat the PVC and flatten all but about a 1.5-2'' portion which will fit into the end of the stock.
I also tapered each piece on the band saw because I thought it looked better that way.
Once you have each piece made all that remains to be done is to glue them into place.
Step 11: Attaching the Tactical Rails
To attach the tactical rail mounts I simply glued them on with hot glue, ensuring that they were aligned and centered on the main body. If you wanted to go the extra mile and guarantee that they will never fall off you could use epoxy.
Step 12: Making the Fuel Cell
For the fuel cell you will need a 7.5'' piece of sponge cut into 5 equal parts, and an 8.5'' steel rod, as well as your 1 1/4'' threaded plug which attaches to the threaded adapter. Using a liberal amount of hot glue, attach the steal rod to the inside of the threaded plug, making sure that the rod is centered and extending straight out. Once the hot glue has cooled, push the rod through each of the sponges adding a layer of hot glue in between each section to ensure the fuel is equally distributed in the entire fuel cell.
Step 13: Preparing the Scope for Painting
To prepare the scope for painting I covered each lens with masking tape then trimmed any excess off with an exacto knife. I then proceeded to attach the scope to the gun for painting.
Step 14: Painting!
I first gave the entire thing a base coat of black. I then used desert tan to give it a camo look. I suspended it from my garage ceiling and that made painting the entire thing a breeze.
When painting PVC pipe it is imperative that you go in very thin, light coats to prevent the paint from pooling up and dripping.
Step 15: How to Operate
To use this PVC potato shooter first you will need to soak the fuel sponges in at least 91% rubbing alcohol. (Anything less is not flammable) screw the fuel sponge into the gun then prime the combustion chamber by using a spray bottle to spray 1-2 sprays of rubbing alcohol into the chamber through the auxiliary combustion chamber access port. Once the potato shooter is primed, take off the barrel and load it with a plug of potato, place the barrel back on, then pull the trigger. To fire again, all you need to do is give the air pump 6-10 pumps to replenish the oxygen in the combustion chamber, and reload.
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I'm building this....
1) the 3" combustion chamber piece which is sealed at one end...the sealed end is down. Right?
2) has anyone decreased the size of the barrel to 3/4"?
3) the auxiliary combustion chamber plug...is that the threaded one where the air pump line is?