Step 3: Bundle the jugs
The 2 gallon jugs fortunately have two grooves that can be used to tie them together. I used some basic white string that I got at the hardware store.
I wrapped the string completely around the outside of the front groove on all of the four containers. On one end of the string I tied a loop using a figure-8 knot (although, any old knot should do). With the other end, I cut the line a little long and pulled the extra string through the loop I just made. I made sure the string was in the grooves all the way around the four containers. Then I folded the string all the way back and tied it onto the taught part of the string using a slipknot. I pulled this knot to make sure the bundle was very tight.
To begin with, I would then glue the slipknot in place using hot glue, but I later realized that this wasn't necessary.
I then repeated this process for the other groove until there were 2 taught bands wrapped around the whole bundle.