This simple jig makes tying balloons (especially water-bombs) a lot quicker, and makes it a lot easier to build up your ammunition for April Fools.
Step 1: Materials
For this prototype, I used a dead Sharpie pen and some spare timber.
Tools included a small saw, sharp knife, drill+wood bit and a circular file.
Step 2: Cutting.
The slot needs to be wide enough to slide the neck of the balloon into, and smooth enough to avoid snagging the balloon.
I cut into the pen with the saw, twice, then smoothed off the edges by trimming with a sharp craft knife.
Then, on the side of the pen that will end up at the bottom, I cut a wide, vaguely V-shaped notch to momentarily anchor the end of the balloon during knotting.
Step 3: Drilling, filing, hammering.
I drilled a pilot hole first, then used the large bit to drill a hole for the pen to wedge into.
The hole turned out to be ever-so-slightly too small.
To make the pen fit, I used a round file to enlarge the hole slightly. Do not be tempted to hammer the pen into the hole - you will snap off the end of the pen.
Instead, grip the pen firmly with a pair of large pliers, and then hammer the pliers beside the pen.
Make sure that the V-shaped notch ends up at the bottom of the pen.