Homemade Bottle Cap Shooter

There is nothing better than building things with your own two hands. It is even better when the thing you are building can shoot things!!

What we are doing and our objectives:

In this project you will learn how to turn the potential energy from a rubber band into a powerful cap shooter that can take down targets! This project is easy to do and can be made by anyone.

Parents, this is a great project to introduce your younger kids too. They will have a chance to be creative and learn how to apply engineering, design, and construction skills to real world situations. The best part is you can do this project with easy to find store bought supplies. If you do not have one of the tools listed this is an easy project to get creative with and improvise.

Although I use power tools in this walk through, it is not necessary. This build can be accomplished with just hand tools and glue. This would allow a much younger audience, 8+ years of age, to accomplish the builds without any supervision.

Otherwise, if you would like to use power tools adult supervision should be used. Or older kids can do it on their own, 14+.

Practices:

Creativity

Critical Thinking

Making and Doing

Standards:

Integration of Knowledge, Technologies, and Practices

Nature and Characteristic of Technology and Engineering

Core Concepts of Technology and Engineering

Context:

Material Conversion and Processing

Get Started!

WARNING:

ADULT SUPERVISION FOR CONSTRUCTION AND USE IS RECOMMENDED.

TOOL USE CAN BE DANGEROUS AND LEAD TO SERIOUS INJURY OR DEATH.

THE BOTTLE CAP SHOOTER CAN CAUSE SERIOUS INJURY AND BODILY HARM.

USE ONLY FOR TARGET SHOOTING.

Main Supplies:

· One piece of 1’-0” of ¾” PVC Pipe (2ft piece will cost $2.53)

· Two pieces of 0’-5.5” long ½” PVC Pipe (2ft piece will cost $1.86)

· One 45 deg ¾” Bell End Elbow ($1.25)

· One ¾” x ½” x ½” T-Slip ($0.74)

· One Clothespin (A pack of 50 costs $2.14)

· A couple of rubber bands (A large pack costs $2.04)

· Two small screws (I bet you can find 2 in your junk drawer)

· One 1’-0” x 1 ½” x ¼” piece of wood (Width and thickness can vary, price varies)

· One Popsicle Stick (A big bag is only a dollar)

Optional Supplies:

· Two ½” PVC Caps, slip on ($0.64 ea)

· Two ¾” PVC Caps, slip on ($0.79 ea)

· One ¾” Saddle Tee ($2.05)

· One 5” long ¾” PVC Pipe (Use leftover PVC from required supplies)·

· One threaded ¾” adapter ($2.50)

Tools:

· Hot glue gun

· Drill (A screw driver will also work, it will just be slower going)

· Drill bit for pilot holes (One that has a smaller dia. then your screws)

· Driver bit (One that is appropriate for your screws, i.e. phillips, torx, flat head, etc.)

· Cutting Device (Saw, pipe cutter, etc. But the measurements are not set in stone, you can vary the lengths of the pvc pipe to anything you want. We will talk more about that later.)

· Measuring Device (ruler is ideal, once again you can do without)

· Marker/Pencil/Pen

In this step we are going to need our ½” and ¾” PVC Pipe along with the wood you have chosen. For tools you will need something to measure with, a writing tool or something to mark with, and your saw or pipe cutter.

The wood I have chosen for this project is 1.5" wide and 1/4" thick. These dimensions are not required. As long as you have a piece of wood that is relatively wide and thin it should be just fine.

• Measure your 3/4" PVC pipe and your piece of wood to the same length. In this case I am going to cut them to 1 foot long. (The length can vary for your application, as long as they are the same length it will work just fine)
• Cut your 3/4" PVC pipe and wood using your saw and/or pipe cutter.
• Take your 1/2" PVC pipe and measure out two 5.5" long pieces. (Once again, your length can vary if you like, as long as they are the same length and shorter than your 3/4" PVC pipe)
• Cut your 1/2" PVC pipe pieces just like we did before.

We will need our two pieces of 1/2" PVC pipe, 2 screws, drill, drill bit, and driver bit.

I am using two #8 x 1.25" finishing screws which use a T15 Torx bit. But you can use any type of screws you want.

If you do not have access to a drill a screwdriver will work as well. It may just take a lot more effort to fully screw in the screws of your choice.

• Take your drill and install your drill bit. Ensure your bit has a smaller diameter then your screws. I am using a 3/32" drill bit but have also used a 1/16" drill bit.

• Drill one pilot hole at the end of each of your 1/2" PVC pipes. There is no seta distance from the edge of the pipe, but 1/2" to 1" from the edge is recommended. (Drilling a hole in a curved face can be difficult and dangerous, it is easy to slip and hit your finger, use caution)

• Once you have your pilot holes drilled switch your bit to the appropriate driver bit for your screws

• Drill one screw into each of the 2 pilot holes, ensure there is at least a half inch of each screw protruding out of the pipe.

In this step we will need all of our required PVC Pipe supplies. The two 1/2" PVC pipes we just cut, the 1ft long 3/4" PVC Pipe, the 45-deg. elbow, the T-slip, and if you have a 3/4" and 1/2" PVC end cap.

No tools are required for this step but using a glue gun to secure the parts is an option.

• First, slide your 3/4" PVC Pipe into the 45-deg. elbow, it will only fit one way. (If the pipe slides around more than you want, use some hot glue to secure the joint)
• Now take your two 1/2" PVC Pipes and slide them into either side of your T-Slip. Both screw should be facing up and in the same direction.
• Take the T-slip with the 1/2" PVC Pipes and slide it onto the other open end of your foot long 3/4" pipe. Ensure the elbow is at a 90-deg. angle from the two 1/2" PVC Pipes. (It is a handle)
• If you have an end cap slid it onto the other end of your 45-deg. elbow.
• If you have the two 1/2" end caps put one on each side of 1/2" PVC Pipe on the front of your shooter.

Now take your 1ft long piece of wood and the piping you just assembled along with your hot glue gun.

• Put a dollop of glue on both of the joints on top of the piping, it does not have to be that much. (This should be the two highest points as shown in the picture)
• Take your piece of wood and place it centered over the length of your 3/4" PVC Pipe.
• Apply pressure to the wood until it is fully seated on the joints. (Be mindful of hot glue dripping out from the sides and landing on skin, this can cause burns)
• Allow to dry for a few minutes.
• Once dry come back and add more glue along the length of the pipe to allow for extra reinforcement. (There is not set amount of glue to use, just use your best judgment)

We will need one Clothespin and one Popsicle Stick and some sort of glue to hold them together, I am using a hot glue gun.

If you are using a hot glue gun, please be careful. Adult supervision is recommended.

• Put a long thin trail of glue on top of the clothespin. (I prefer to start behind the metal spring)
• Carefully place your popsicle stick on top, make sure to center it.
• Apply light pressure to create a good seal between the clothespin and popsicle stick. (The pressure can cause hot glue to drip out onto your fingers and cause burns. Watch the glue while doing this)
• Let cool and solidify for a few minutes.

Take your current shooter, firing mechanism, and your hot glue gun.

• Add a thin line of glue to the back side of the deck just slightly shorter that the clothespin, ensure that it is centered.
• Apply the firing mechanism to the glue keeping it centered. (I prefer to have it hanging off that edge of the deck slightly, but this is preference)
• Apply pressure to the firing mechanism to ensure bondage.
• Allow to cool.
• Add additional glue if necessary to ensure a secure bond between the firing pin and deck.

First, let's look at rubber bands. The rubber bands on our shooter generates all the force we will be using. Rubber bands can store potential energy just like a spring. In fact, there is a formula that describes how much potential energy in stored in a spring, or in this case, a rubber band.

PE = (1/2)(k)(x^2)

But to make it easy to understand, the thicker the rubber band and the farther we stretch it the more energy it can store.

If we take 2 rubber bands that are identical, then we stretch one 2 inches and the other 4 inches, the rubber band stretched 4 inches will have more stored energy. This means it can fire something faster and further than the 2-inch stretched rubber band.

So, find yourself a few rubber bands that you think look good. keep in mind that when installed on your shooter, you don't want to over stretch your rubber band and risk it snapping. You also do not want your rubber band to be too long. If it does not stretch at all you will not be able to shoot anything. You may have to experiment with the type of rubber bands and the amount needed to get the desired results.

With that said....

Take your current bottle cap shooter and your rubber bands. I am using 2 rubber bands that are roughly 3" in diameter.

• Attach the rubber bands to one another using a girth hitch (If you are using more than one rubber band)
• Use another girth hitch to attach each end of the rubber band to each side of the 1/2" PVC Pipe over your screw. (The picture above shows how it should look)

I recommend using a girth hitch to secure your rubber bands, but other knots will work too. If you need help tying a girth hitch, check out the video below for a walk through.

This is not something you have to add, but if you would like your shooter to look a little cooler and want the added stability, make yourself a foregrip.

You need your 3/4" Saddle Tee, one piece of 3/4" PVC Pipe (the length is your choice), one threaded ¾” adapter, and a ¾” end cap.

• Slip your length of 3/4" PVC Pipe into the threaded adapter.
• Slip your 3/4" cap onto the other side of the PVC Pipe.
• Take your Saddle Tee and screw in your assembled PCV pipe.
• Now take your new grip and snap it onto the bottom of your bottle cap shooter. This will take a little bit of force but is easy.

You can now move it back and forth to find a comfortable foregrip position. If you would like you can use hot glue to secure it in place against your shooter. I do not do this; I like to be free to move it around or take it off when needed.

This is a bottle cap shooter, but it can shoot much more!

In the picture above you can see cut wooden dowels, wood squares, left over PVC Pipe of different sizes, and different bottle caps. Personally, I enjoy using hard oak dowels that are 1.25" in diameter. They are a little denser and heavier so they have a great kick when fired! The sky is the limit when it comes to choosing ammo.

How to load and fire the bottle cap shooter:

WARNING:

ALWAYS COCK AND LOAD THE BOTTLE CAP SHOOTER WHILE AIMING IN A SAFE DIRECTION. ACCIDENTAL DISCHARGE CAN LEAD TO INJURIES.

• Pull your rubber band back to the firing mechanism.
• Open the firing mechanism by pushing down on the lever.
• Place your rubber band into the firing mechanism and release it so it can close. (Ensure the firing mechanism is fully closed and the rubber band in securely seated before letting go of the rubber band)
• The firing mechanism should be securely holding the rubber band back in place.
• Now place your bottle cap in front of your firing mechanism, it should lie flat on the deck.
• Now that you're ready to shoot, aim at the target, when ready press down on the back of the firing mechanism (The end of the popsicle stick) and your new bottle cap shooter will fire!

Make it your own.

There is no one right way to build the bottle cap shooter. You can combine and change any part of it you would like.

One shooter above is made out of 1/2" PVC Pipe. Then later a 1.5" PVC Pipe was added as a grip. It is twice as long as the one we made in our previous steps, but it uses the same 2 rubber bands. The added stretch length makes the distance it can shoot much further. Not only this but the firing mechanism uses 2 clothespins to hold back all that stretched force.

Another example is made of just square poplar wood, no PVC Pipe.

As long as you have your rubber bands and a clothespin you can make a million different versions. So go wild, get creative, and come up with something cool and unique!