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 with ...