We’ve assembled the necessary pieces:
- 20″ of each: 1″ and 1 1/4″ PVC pipe (usually available in 10-foot sections, hence the suggestion to make six water guns at once)
- End cap for each diameter of pipe
- One 3/4″ plug (generally for use on 3/4″ pipe)
- Number #15 O-rings
- Dental floss
And used PVC cement to attach them. We also bought some curved pieces to make a better handle.
We used a Dremel to bore out the bottom end to fit the push plug and then wrapped about a foot of dental floss below where the O-rings should be and then rolled the two O-rings on top of that and put the third O-ring seated between.
The water cannon turned out great but was a bit too big for our four year old son to handle. We are working on a smaller one for him right now but in the mean time it’s a great toy for Dad!