What do you mean by hot glue and pin? Do you suggest I bolt it in rather than glueing it?

Taking a break from this build and looking at it with fresh eyes really helped me out. Playing around with it I discovered that the piston was just slightly too loose and when pressurized the piston would not seal the barrel because too much air would leak around instead of forcing it up against the...

Sigh, the piston has defeated me again. The piston in the picture below moves nicely with a 2 finger push and I was satasfied with my work until I tried filling it. Air leaked out of the barrel again, not an extreme amount of air flow like last time, but to the point where pressure won't build up.

Well, after hours invested on the Bondo piston it broke when I was tapping the hole for the bolt. I'm glad it did I guess because if it was structurally weak then I would not want it in the cannon anyways. It was probably because of air bubbles trapped within the Bondo. Any tips for preventing air b...

I just casted my first piston out of Bondo :o it's fresh out of the mold I put it in so it needs some filing and sanding. I'm going to epoxy rubber to the top of the piston for it's sealing face. Is there any recommended thickness for the sealing face? I have really thin rubber from an inner bike tu...

Fenrir, what do you mean by soft enough to seal? I intend to use the cannon to it's full potential which from what I understand is 100-120psi. Also what are the physics behind having the pilot volume small? Jack, Do you have any experience with Bondo? Would it be similar to that of a piston made out...

Hey guys, I'm having trouble with not only piston design but piston actuation as well. Every piston I have designed so far has failed as instead of pressurizing the chamber all the air leaks out of the barrel. The pneumatic cannon I have built uses a 1.5" tee that reduces to a 1" barrel. Below I hav...

Thanks for the info 1nxtmonster! Based on your suggestions I have created a new schematic based on your suggestions. I am going to be building the cannon next week as I'm off from school, so you and noname have been beyond helpful for this newbie! :lol: Last thing, how dramatically would performance...

Thanks noname! Is there one choice that's better than the other for having that tight air-lock seal that maximizes air flow and piston reaction time? For example an additional tee one with the trigger valve (PVC ball valve) and on the other port the quick connect hooked up to a series of couplings t...

I am building my first cannon ever, and have decided on a barrel sealing piston design using SCH40 PVC. I have attached a hand drawn diagram of my build plans. To my knowledge the build is pretty solid and the piston will be be made out of Bondo (a lightweight car filler) and will be using pieces of...