The Ping Pong Ball Mauler

Today, I have the great pleasure of introducing to you the Ping Pong Ball Mauler, the only fully automatic, large capacity, ping pong ball launcher.  This is the first do it yourself project I have undertaken with my new company, Outsmarting Technologies LLC .  Please visit the website to see other recent creations or check out my construction blog here or here .

      Back to the Ping Pong Ball Mauler.  This creation is unlike any other pneumatic launcher created. Traditional pneumatic launchers utilize a low volume, high pressure system and are usually only capable of launching a barrel loaded projectile (commonly a potato) and then can launch this object far, but at a very slow rate, often taking more than a minute before a follow up launch is possible and would be very dangerous to hit someone with.

     However, the Ping Pong Ball Mauler is completely different.  By utilizing a high volume, low pressure system provided by a standard shop vacuum, The Ping Pong Ball Mauler can launch hundreds of balls a minute, continuously, without having to reload!  By utilizing a 55 gallon poly drum to hold over 2500 ping pong balls, the user can sustain a rapid rate of fire so long as there is ammo left.  It has a maximum firing capacity of 300 balls per minute (as long as nothing jams).  The best part is, the balls are so light and harmless that they can readily be used to attack and unsuspecting friend with (be sure not to aim for the face as one to the eye may cause damage). 

        I have organized each step of this Instructable into 5 sections to try and make it as clear and easy to follow as possible:
1) Step Aim: where I discuss what we will accomplish/create in this step.
2) Tools: which tools will be required to perform this step.
3) Materials: what materials from the part list will you need in this step.
4) Directions: step by step directions for this particular component's construction.
5) Tips: where I make note of any problems I ran into and ways to avoid them during your building process.
      Of course, there will be countless photos, diagrams, drawing, and links to supplement each step and avoid any confusion (you may need to view full size to see all the dimensions and notes properly).

     The best part of all of this is its simplicity to make.  Anyone can build this as there are no particularly difficult skills to learn and all of the parts are readily available at any home improvement store.  This is a great weekend project and is an absolute blast to use.  So what are you waiting for, let us get started!  

I recommend reading through all of the steps before attempting to build it and ask any questions before you start.  Also, feel free to be creative and make whatever changes you would like, there are plenty of ways to make this and customize it to your needs. 

Again my name is Christian Reed (going to be a junior at MIT this year in Mechanical Engineering) and feel free to  look at my company, personal, or blog websites.  Of course, feel free to message me or otherwise contact me with any questions or problems you have and I would be happy to help.

Tools

- Welder (don’t worry if you don’t have one, the frame can easily be built from 2x4’s cut in half (the long way) without much of a problem
- Angle Grinder
- Dremel Multitool
- Wrench and Socket Set
- Pliers
- Spring Clamps
- Utility Knife
- Jig Saw
- Screwdrivers
- Metal Cut off Saw

Materials

See attached PDF

Step Aim
Here, we will begin to make the basic structure that will hold the device together by welding the first part of the frame.  Note, if you are building this out of wood, the basic shape will probably be the same and you can certainly follow these guidelines or come up with another design that you have in mind.

Tools
- Welder Setup
- Angle Grinder
- Magnetic clamps (make life a lot easier)
- Metal Cutoff saw (or a metal blade on whatever saw you are using)

Materials
- 3/4” Square tubing
- 5/8” Bolts

Procedure
1) Begin by cutting the metal for the entire frame.  Its better just to get it out of the way and then just be able to fly through the welding aspect once all the pieces are cut and ready to go.   Clean up any rough edges with the grinder so everything fits together nicely.
2) Grind off the zinc coating (while wearing a regulator as this will create toxic fumes and dust) from the bolts in the back part where they will be attached to the frame (see picture). 
3) Begin on the ground and weld the basic rectangle using the magnetic clamps to ensure all corners are right angles.  For new welders, always start by making tack welds to hold everything in place then go back later to complete the weld.
4) Make the wheel angles separate from the frame first then once the angle is completed, weld that to the frame
5) Attach the bolts (taking care to make sure they are level both horizontally and vertically and perpendicular to the frame in both directions.


Tips
- I forgot to write the size for the lights.  The top bar is 7" long and the connection to the frame is 2" long.
- Check out this instructable to learn more about MIG Welding 
- Grind down all welded joints to smooth them out.
- Never overlook safety.  Wear all necessary equipment when welding
- Where a regulator when grinding as it creates a lot of dust
- When cutting the obtuse angles for the barrel support bars, take extra care to secure the bar down as you will cutting at an unusual angle

Step Aim
In this step, we will complete the frame by welding the remaining parts togeather.

Tools
- Welder Setup
- Angle Grinder
- Magnetic clamps (make life a lot easier)
-Spring Clamps


Materials
- 3/4” Square tubing

Procedure
1) Align and assemble the bar that comes up perpendicular to the frame on the ground and then weld it to the frame.
2) Attach the cross bars on the base level of the frame
3) Weld the angle pieces that will hold the barrel to the frame.  It is helpful here to have a helper or use the spring clamps as shown to help hold the bars in place
4) Finish welding the frame by assembling the light holders on the front of the frame.


Tips
-Soapstone is a great device for marking alignments and locations on metal and are found at any home improvement store in the welding section

Step Aim
In this step, we will create two tank adapters which will allow the 2 ½” shop vacuum hose to be connected to one of the two openings in the 55 gallon drum.  Here you need to be somewhat creative as my setup works for the hose and the shop vacuum that I have but this entirely depends on your setup.  However, the procedure will probably be the same, only different kind of fittings.

Tools
- Dremel
- Drill

Materials
- Course threaded Poly Drum Cap (Comes with the barrel and covers the course threaded hole.
- 2” Male PVC adapter
- Epoxy
- (2) Shop Vacuum fittings (basically connections that have the unglued side able to connect to whichever hose you want to use

Procedure
1) The easy one is the NPT (fine threaded one).  Simple glue the end of the Vacuum fitting that will not be connected to the hose to the end of the cap.  Once it is dry, it will screw right into place and allow the tube connection for the ball exit hose
2) The second fitting requires a little more work.  Start off by drilling out the center of the cap.  Use the dremel to open the hole enough that the Vacuum adapter will fit in but not so much as you ruin the structure of the threads or cap (it still has to be screwed into the hole.)
3) Look at the picture for reference as this is a very simple step once you see what to do.


Tips
-Just be careful making the second connector as we do not want to ruin it.  There may be a better adapter for sale online but this is a simple and cheap way to make one.

Step Aim
Here we will make the ball joint which will hold the PVC barrel and allow the barrel to be held in almost any position. I have drawn out this procedure as it may be hard to understand.

Tools
- Welder Setup
- Angle Grinder
- Magnetic clamps (make life a lot easier)
- Bench top Grinder
- Dremel Multitool

Materials
- 3/4” Square tubing
- Trailer Hitch Ball
- Epoxy
- 1 ½” Male Adapter
- 1 ½” Flat Endcap

Procedure
1) Start by welding the frame together for the holder.  Again, be careful when cutting the obtuse angles.  Grind the welds once completed.
2) Using the bench top grinder, grind down the base of the Trailer hitch ball so we can slide on the PVC end cap later on.
3) Use a radial arm saw or chop saw to cut off the bottom part of the PVC end cap.  MAKE SUYRE IT IS CLAMPED DOWN AND YORU HAND ARE NO WHERE NEAR THE BLADE.
4) Drill a hole in the end cap.  Using the dremel, make the hole bigger until it is just about 2-4mm away from the wall of the end cap.  Ensure that it will slide on the ball and lines up with the top PVC adapter.
5) Epoxy the two pieces together.  You may need to spin it often to ensure that  it does not get stuck to the ball. 
6) Finish up by welding the ball and PVC assembly to the top of the frame you just made at the beginning of this step.
7) Feel free to paint the frame and PVC joint now if you would like.  Try to avoid painting the ball as it will just chip off.

Tips
-Make absolutely sure the end cap that you are cutting is securely held down. 
-Spread epoxy generously on the outside to ensure a solid connection.

Step Aim
In this step, we will assemble the PVC frame for the barrel, from which the balls will exit the launcher as well as pick up speed.

Tools
- Saw to cut PVC

Materials
- 4” PVC
- 1 ½” PVC
- ¾” PVC
- 2” to 4” PVC Reducer Fitting
- 2” to 1” reducing bushing
- Female 1 ½” threaded section
- Plastic Epoxy
- (4) ¾” PVC 90 degree bends
- (4) ¾” PVC tees

Procedure
1) Cut the 4” PVC (for the tank) and the 1 ½” PVC (for the barrel) to length. 
2) Assemble the PVC pipe together using the picture and diagram for reference.  Be sure to prime (Purple) and glue (white/clear) all the pieces together.
3) Sand a flat section on the 4” Section where the female adapter will be epoxied down.
4) Epoxy the female adapter to the section you sanded flat
5) Assemble the PVC handles (do not glue before you know it will fit) and position on PVC barrel then epoxy into place.  Again, this needs to be an exact/close to exact fit so be careful to ensure this is the case when performing this step.
6) Paint barrel color of choice

Tips
-Do the PVC gluing outside as the fumes are not good to breathe in.

Step Aim
Here, we will make a couple of changes to the 55 gallon poly drum in order to make it more useful in our creation as well as painting it (with a cool design if you want). I found my barrels on craigslist and got it a lot cheaper than if it was new so it may be worth looking around locally first.

Tools
- Jigsaw (you could probably use a dremel too)
- Drill with ½” bit

Materials
- 4” PVC Threaded Drain Cap
- 4” PVC Drain cap connector
- Plastic Epoxy
- Spray paint

Procedure
1) Start off by tracing the outline of the PVC drain cap connector on the bottom of the barrel on the same side that the course threaded opening is on the other side of the barrel.  This is important as we need this for everything to be oriented properly.  Note, the barrel has two openings, one course threaded and one fine threaded NPT (the threads are closer together). Make sure again that the drain cap holder is on the bottom of the barrel lined up with the course threaded opening (which of course will be on the ground now as you have flipped the barrel over.
2) Drill a ½” pilot hole somewhere in the outline you just traced.  This is where we will begin the jig saw cut
3) Using the jig saw, cut the hole for the drain cap holder.
4) Cover the edge of the drain cap with a layer of epoxy and then insert into place and then twist 90 degrees to ensure the epoxy is spread evenly.
5) Once the epoxy is dry, the time is right to paint the barrel so it can dry while you work on the rest of the frame.  Using a primer is helpful to allow the paint to stick better and not chip off (which it will inevitably do).

Tips
- Double check to make sure you are cutting the right size and location

Step Aim
The fabrication phase of the project is pretty much done, now it is just a matter of securing everything down and assembling the various components.  Here, we will paint the frame and then attach the wheels and lights.

Tools
- Screwdrivers
- Drill

Materials
- Spray-paint and primer
- LED Strobe Lights
- (4) 10” Wheels
- #10 1” bolts and nuts
- #10 ½” bolts and nuts


Procedure
1) On a cloth, paint the top and bottom of the steel frame so it doesn’t rust.  I first put on a white primer coat and then went over it with a green camouflage color for the final layer. 
2) Once the paint is dry, attach and bolt the wheels into place on the frame
3) Drill two holes that line up with the holes on the LED Strobe light bracket.
4) Using the #10 nuts and bolts, secure the lights in place.  Run the wires to the center of the frame (using zip ties) as this is where the power source will eventually be.

Tips
-Make sure to paint everything otherwise the steel will rust

Step Aim
We will attach and secure down the air tank and vacuum to the frame as well as the airline which will be used to clear balls in the event of a jam. 

Tools
- Dremel
- Wrench Set

Materials
- 11 Gallon Air Tank
- Hose Clamps
- (2) Ratchet down straps
- Air Line Regulator
- (4) Hose barb to ¼” MNPT
- Shop Vacuum you will be using
- Zip Ties
- ¼” Air Hose
- Teflon Tape


Procedure
1) Use the Dremel to carefully remove the bottom support from the tank.  I am still not sure why there would only be one but regardless, it needs to come off.  MAKE SURE YOU DON’T HIT THE TANK WITH THE DREMEL AS THIS MAY CAUSE THE TANK TO FAIL.  Just take off enough to remove the brackets; it is okay that if a little extra remains.
2) Once the bracket is removed, secure the tank with the Rackets to the frame with the gauge facing up.
3) Place the shop vacuum in the frame and use hose clamps as necessary to ensure that a secure connection is created.
4) Start to put together the hose line.  I have included a drawing to aid in your assembly.  Make sure all connections are secure and use Teflon tape for extra leak protection. 
5) Double check everything is secure down properly.


Tips
-Make sure everything is securely fastened to the frame so it does not come loose or fall off while the cart is moving.

Step Aim
We will place the barrel on the frame and secure the tank to the frame as well as the holder for the PVC barrel. 

Tools
-None

Materials
- 55 Gallon drum (the one we modified)
- Ball Joint we made
- PVC Barrel we made
-(2) Ratchet Down Straps

Procedure
1) Place barrel on the frame and make sure both holes in the back are accessible and ensure the frame will not interfere.  The fine threaded hole should be on the bottom.
2) Strap down the barrel to the frame and place the ball joint so that it is held in place by the straps.
3) Screw on the barrel to the ball joint.

Tips
-Ensure that the frame does not block access to any of the holes as we will attach the hoses in the next step.

Step Aim
The end is near!  Here we will finish up by attaching all of the hoses and finishing up the project.  

Tools
- Drill

Materials
- 2 ½” Shop Vacuum Hose
- 3/8” Acrylic Rod
- 3-Way Electrical Outlet
- Outlet switch with remote cord.

Procedure
1) Drill a hole near the top of the barrel for the rod to slide into.  This will serve as the operators mixing stick to clear out clogs and control the rate of fire.
2) Attach the shop vacuum hose coming from to vacuum to the course-threaded adapter and then to the top hole on the barrel.
3) Attach the other Shop vacuum hose to the PVC barrel and the other end to the NPT threaded hose adapter and screw into the bottom of the barrel.
4) Place the 3-way outlet as shown and scure down with a zip tie. 
5) Run the power cord to the barrel handle so you can control when the vacuum is on and off
6) Use pictures for reference.

Tips
-Make sure all wires are secured down and not loose

And now you are done!  Congratulations and enjoy.  There are countless ways to have fun and enjoy this wonderful creation.  The sky is limit.  Personally i have used this at a recent party to launch ping pong balls all over the backyard, put it in the back of my pickup truck to make it completely mobile, and used it to attack unsuspecting friends.  Its a lot of fun as you can see from my video.  Just be sure to be safe and careful when using it.  Enjoy and happy building.  

Before I undertook this invention, a lot of planning and testing went into this creation.  A lot of ideas were toyed around with (in case you were thinking of trying them), that I know will not work.  I have shared a few here to show you my thought process for coming to the final, functional, design.

1) Adding compressed air to the barrel does not speed up the ball

2) The balls will inevitably get clogged somewhere.

3 Since the mauler is mobile, make sure everything is secured down to the frame.

4) The barrel and launcher work better when there are about 300 balls in the launcher and you do not need to use the stirring rod as much, however, the barrel can hold more than 3000 balls, you just need to use the stirrer to ensure nothing gets clogged.

5) Use the stirrer to control your rate of fire and prevent jams from forming.

Please let me know if you have any suggestions, comments or improvements and i would be glad to help in any way I can!