really? dangit so THATS how you tell. I think i will just take my chances though because i dont think im going to be taking past like 60 psi. thanks for the concern though. this is just one of those guns that i made for portability, not power.

hey while were on the topic...anyone live in ohio? i live in fairfield OH. close to cincinnati

huh? you mean the valve that i used (schrader) to fill the gun? any auto parts store will have those, as well as bike shops

this is my new diaphragm pistol. The chamber is 1 1/2 inches and the barrel is 1/2. The diaphragm is just a circle of 3/16 neoprene. 3/8 inch ball valve for the pilot valve. i was going to use a blowgun with a hose so the gun only took one hand to operate but it didnt release the air fast enough. oh...

yeah 1/4 inch sounds a bit big for metal bbs. try airsoft.

but why not just put a threaded cap instead of messing with the o rings and stuff?

the part that has always confused me about valves like this is how does the end cap hold pressure when its just screwed in?

with dry ice you can customize the tank though. Valves, size, popoffs, gauges, ect.

i still would buy the gas and a reg though before i would do this

problem is you would have to carry around the dry ice in highly insulated containers and have all the gear to handle it. i had the idea once to make a metal chamber to hold the dry ice and pressurize it up to like 2000 psi. then regulate it to like one hundred and you could get many shots out of it....

i think hes trying to say 923 pounds of force because it would be 100 pounds PER square inch. but i doubt you would have 9 square inches

haha never thought of that before. good idea. i would try it if i didnt have to clean it all up

two inches sounds plenty. and about the porous thing, you have to put a piece of neoprene or something on the face of the piston anyway and the rubber wont be porous

the ignitors will ignite the fuel every time thats for sure. i think the reason alot of people dont use this method though is because you have to pay for each igniter as opposed to buying, say,a stun gun for 30 dollars and never having to pay again.

i would just use a non threaded but im trying to fit in a schrader and 1/4 inch nipple onto a 1 1/2 inch threaded cap. the non threaded ones would take up too much room in the inside of the cap

none of my local hardware stores carry them threaded. but thanks for all the help. ill probably just order them from mcmaster