SubsonicSpud wrote:Simple thread,
How long have you been in the hobby? and what got you involved?
Myself I started out with Air/Water rockets in primary school about 16 years ago
SubsonicSpud
Good grief. As a kid I had one of those air/water rockets with the pump launcher. I had that in grade school, so if you go by that, I've started almost a half century ago.
Went through high school, military with real live ammo, and then into electronics. Didn't really get the bug until about 10 years ago when I built my first piston, a 3/4 inch coaxial. The piston was huge, very long and fairly slow, but it was my first home built. After that built several other models with a common problem of pistons either breaking the valve or the piston itself shattering.
This was the time I heard of combustion spudding and learned a little about ABS surviving the burst of a combustion cannon. This is where I decided to test ABS. I had no easy way to make a traditional piston with the stuff due to the limited selection of pipe sizes, so the rope pulled QDV test cannon was born. It outlived the 4 PVC cannons before it.
After the ABS cannon, I started playing with tweaking the dimensions on piston valves and learned how QEV's work, which led to the construction of the Mouse Musket, a 1 inch cannon with a 1.5 inch barrel sealer piston sitting on a 1.25~1.3 inch valve seat (o ring). This became my favorite toy as it could put gumballs through 1/2 inch plywood. Due to the SSSSSssssssBANG of a true QEV, it tended to shatter piston valves. After breaking 3 pistons over a couple years, it gathered dust and the ABS Test cannon was the annual event at the church camp launching apples.
Last year, the T shirt competition lit the spark again.
I knew of what materials failed on a regular basis and what held up. I was worried the non pressure rated pipe would count badly against us in a competition judged by engineers, so more testing was in order. The ABS Test cannon valve was a good performer, but PVC and rope pull.. Needed serious improvement.
First on the agenda was a new design. Steel tank.. Solves DWV problems and brittle PVC. The cost factor.
Disposable steel tanks are free
. Steel tank, steel cap, PVC piston, higher pressure maybe.. not good. More testing in order.
HDPE was tried. Made a HDPE piston on the drill press for the Mouse Musket to test the new material. Light strong and highly impact resistant. In testing found the barrel end of the Musket was leaking through the reducer.. Examination found the Coupler and Reducer was cracked from being tipped over on the floor too many times. Time to retire it before the crack migrates to the chamber wall.
Made the Steel Quick Dump Valve cannon just to see if it could be built with the tools my assigned high school had on hand. It was a success. Shared the news and made a trip to Arlington to share the findings and do a side by side comparison right next to a 1.5 inch sprinkler valve cannon.
Arlington wasn't too enthused on trying to build another launcher since they had one that works, but the performance was such, that to win, it could be the ace up the sleeve we had. They built one. Worked like a charm.
After the competition in showing the engineers how it works and was built, it became way too big to carry everywhere, so I built a working model, the Marshmallow Cannon. It fits in my lunch box and is my most recent project. On the table is a 3 inch version built in a Propane tank for a 200 PSI 3 inch cannon.
On a future drawing board is a full auto "Bubble Gum Machine --- Gun"
That's my history in spudding.
. Lost interest in the hobby after high school and somehow got the urge to start up again 6years later 
