Water Balloon Cannon // How-To

I made this impromptu water balloon cannon for my kids to play with! It's a simple quick project made to be fairly safe.
Subscribe to my channel:
MORE PROJECTS, POSTS AND EVENTS
TOOLS LIST:
4" PVC pipe (3' long)
3" PVC cap
1" PVC pipe (2' long)
Want to support ILTMS? Get early viewing, exclusive content and more...
BUY A SHIRT, STICKER, PENCILS and MORE!!
FOLLOW:
I used a 3' length of 4" and 1" PVC pipe.
I also used a 3" cap which fits right inside the large pipe.
I traced the smaller pipe on the larger one, marking it a little larger than real life.
I marked a cross line several inches from one end.
I ran it through the bandsaw which cuts the line on the top and bottom of the pipe, to cut both lines.
I used a cut off wheel on a Dremel to trim the piece out.
I switched the wheel out for a grinding stone and cleaned off the corners of the cut. This is to cut down on friction.
I made sure the smaller pipe fit in the slot and moved freely.
Then I made sure there was enough space on each side for a hand, and marked the pipe.
I cut the small pipe along that mark then rounded over the ends on the disc sander.
With the cap, I used the belt sander to carve out a small dip in the  top.
Then back to the disc sander with the cap. I sanded down the entire outside  of the cap to make it's diameter a little smaller.
When you cut the section from the PVC, it puckers a little, making the interior size a little smaller. Sanding the cap makes it fit better inside.
I drilled a small hole in the center of the cap. Drilling from the inside of the cap helps drive the bit to the center. I also drilled a hole in the middle of the smaller pipe section.
I ran a long bolt through a large washer, then through the cap from the inside.
I added the small pipe to the bolt and added a washer and nut to hold the pieces together.
This assembly dropped down into the slot cut in the larger pipe. Then I added some PVC cement to the open end and slid on a 4" coupler.
Since the pipe had the pucker, I clamped the cut edges to the coupler while the cement set up. This helped maintain the correct interior shape.
I cut two pieces of old pressure treated 2x4 into sections about the same length as the pipe.
I drilled a hole through the coupler into the 2x4 below.
I connected them with a short decking screw.
I used some polypropylene strapping to hole the pipe down to the 2x4 on the front and back.
These straps cut very easily with a utility knife, but will hold up well outdoors and are not sharp like the similar metal strapping is.
I also had some used pressure treated plywood that I cut down to a smaller size, with one diagonal side.
I traced it and cut a second identical piece.
I screwed these to the sides of the 2x4 with decking screws. This gave lift to the front of the cannon.
I cut down two more short sections of 2x4 and screwed them onto the front edge of the side panels.
I used 4 decking screws each as these will receive a lot of force when the cannon is used.
On each of the 2x4s I drilled a hole and screwed in an eyelet. This was in line with the cut out in the pipe.
I carefully cut the hooks off of a 4' long bungee cord.
I cut the cord in half and burned the ends with a lighter to stop them from fraying.
I fed the cord through each eye and tied them into a figure 8 loop knot. The other end of this knot can easily slip over the handle piece.
I adjusted both cords until they had mostly even tension on both sides.
The entire thing got sprayed black, which made it really look like a cannon.
On our playset, I drilled a hole in the railing.
I also drilled a hole roughly in the middle of the second 2x4.
I added two washers on the railing then ran a washer and bolt through the 2x4. Second channel: bit.ly/iltms-2