i havent used ignition coils, but i know you can generate a pretty sizeable spark from a television flyback transformer. you can get a good 30 volts out of these things if you wire it right. theyre not too hard to come by either, but you'll want to read up on it a bit if you arent too familiar with ...

piston valves are hard to make sometimes depending on the individual situation and the materials you can get. but they open pretty nicely. i recommend them over diaphragm valves if you can make one work.

i would probably just fabricate a new grappling hook to meet the requirements, but i have a habit of making thigns harder than they have to be, and i like building just about anything myself anyways. if you did make it yourself, you could make it out of a lighter metal like aluminum (if you could fi...

because air pressure has to be on both sides of the valve. the valve opens by dropping the pressure on one side, the diaphragm then flexes to compensate for the pressure drop and the valve opens. if pressure cant get to both sides the diaphragm will just open as soon as pressure is put on it, so the...

i wasnt entirely sure if i did or not (i modded the valve a while ago) so i opened it up to look....i didnt have to seal the hole the guide rod went through because its the same whole that the back of the diaphragm is pressurized through, so sealing the guide rod hole on the diaphragm would render t...

i modded a valve like that recently, except i just removed the guide rod completely and finished it like a valve without a guide rod. i don't know for sure if that has any negative effects but it seems to work just as well as my other valves, and its easier to find than valves without guide rods (at...

beautiful work! im currently working on a similar (sort of) cannon, mine uses a 4" piston and the barrel is flush with the end of the chamber...i'm having problems with the valve, though, what do you use to lubricate the valve?