Hello - I recently set out to build "my son" this cannon:

https://www.youtube.com/watch?v=q508d3k9518

Well, now I can't get it to hold air it seems:

https://www.youtube.com/watch?v=8a2Xx2LNRpg

I followed all of the steps in the Nighthawk video with the following mods:

- I used a CPVC connector ...