handle was traced from another gun onto a 2x4, cut out with a jigsaw, and shaped with a dremel. just held it to feel where it needed to be smoothed down. haha i was using a big file it first it took forever.

yes, the inside of the ball valve is sleeved with SDR21, and the deepest part is done with a little piece of sch40 that i tapered down with a dremel. so when i put in the golfball itll catch and stick in the breech and not roll out the front.

I still havn't got the thing to fire yet though =/ its ...

heh ya i had four pairs of screws for gaps, but they sparked very inconsistantly so i bent three of the pairs together, and the single one left sparks every time.

thx for the advice. running with the new meter volume i got 44 odd psi, still didnt work though.

and its already at 1 gap, had to abandon the four because they very rarely worked, so i just bent all the screws except for one pair until they touched.

i cant measure my chamber volume with water ...

except that you cant really feel the shock on a piezo.

before i was into spudguns i spent a long time making shocking stuff. worked on a glove and eventually made my own little stunprod. i could never get my own tranformers i made to work right though =/

anyways, i wanted to build something that ...

Ok. I finished building my gun, posted it in the showcase section here , and promised all you guys damage pics. only problem is, i cant get it to fire :x

The sparker is working. i can see the spark when i look down the barrel (chamber has definately been cleared! lol) fuel is being mixed.

I ...

they hold the batteries for the fan.

heh, ya ive gotta admit the tape was due to eagerness to finish it, should've waited for more hose clamps.

film canisters hold the batteries for the fans.

one of the pressure gauges is part of the regulator, and the other is on the meter chamber itself, so say when its full? im not sure, i based ...

Just finished my first combustion gun tonight. Haven't fired it yet though, don't want to wake up the neighbors =P but damage pics coming eventually.

Advanced combustion, it's got a chamber fan wired to a switch on the handle, and a piezoelectric sparker wired to multiple spark gaps for ignition ...

just finished the meter, have yet to measure and check for leaks

ok, ive been convinced to go with an all metal meter. and i guess ill have to buy a threading tool >.<

ive been hand threading best i can just using nipples forcefully twisted into pilot holes.

i want a quarter inch npt right?

EDIT: just got back from radioshack, bought an 80mm fan so i can do 3 ...

ok, i wasnt sure which way they worked, looks like its the pressure-makes-them-open-in-one-direction way.

but i was thinking about what lockmanslammin wrote, about the kind that limits flow rate.
so the gun firing makes it close right up, but then as soon as the projectiles out it will open on its ...

i just thought of something, not sure if it will work though, because i might be a little ignorant of how check valves function.

but it you had a big check valve installed in the back end of a combustion cannon, say, behind the fan, facing inward, would it allow free passage of air at atmospheric ...

ahh that would require shipping =P

anyways, im still stumped about the propane meter.

every time ive tapped metal guages or threading of any type directly into PVC its leaked, so im a little wary of that.

and i cant think of anything to go from the regulator to the first ball valve except using ...

i used something like a forstner, its ancient though not as spiffy as they are now. but it was a tad small, widened it a little with a dremel
havnt got a drill press though, had to just do it by hand. marked a dot in the center by eye and drilled a pilot, got lucky i guess.

EDIT: looked it up ...