I think it must be about 2-3 years now, but it has been a very off-and-on hobby. I built a small burst disk gun by accident (I found out I could stick disks of tracing paper between two fittings on my water rocket launcher. I used it as a noisemaker type device for a few days until I discovered attaching a short length of pipe made a crude gun). The mini combustion came next, then there was a period where I was constantly changing and redesigning parts on the mini. Then I made a ballvalve pneumatic with a soda bottle as the chamber (due to my previous experiences with water rockets). That launcher saw a decent bit of use before I just sorta stopped using it. I then made a better, slightly larger mini combustion. After a while I saw the ballvalve gun sitting there but didn't trust the soda bottle after such a long time, so I bought a bit more pipe and made a smaller, stronger chamber. That stayed for quite a while until I was recently thinking about small coaxial pistons. I built one, stealing the filling T section from the ballvalve cannon. Luckily I could just rearrange some parts to get it working again. Most recently, I made my
K'nex artillery gun with my mini combustion, and it is stilll assembled.
So, after all that time, my current arsenel consists of a mere three guns: The k'nex artillery/mini spudgun, my inline ballvalve gun minus the T I mounted the fill valve in (valve is now in end cap of chamber), and my small coaxial piston gun with a pen tube for a barrel. It's been good fun
. Ohh well though, I'm in the process of building a mid-size combustion right now.
