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okay recently i've been thinking about building a .40cal cannon. i've been thinking about making it a piston valve but i might get lazy and just use a sprinkler valve.

my first question is how much pressure could this thing take? i want to make one that opperates at 200-250psi but the highest i've seen anyone say they use is 80 or so. can the pipe take it? could the darts?

second, what is the best way to attach the blowgun? breech loading would be nice but not entirely necessary.

third, which type of valve do you guys think would be better, piston or sprinkler? barrel length will probably be about 3 feet maybe four if the barrel is removable.

SilentCyan wrote:okay recently i've been thinking about building a .40cal cannon. i've been thinking about making it a piston valve but i might get lazy and just use a sprinkler valve.

my first question is how much pressure could this thing take? i want to make one that opperates at 200-250psi but the highest i've seen anyone say they use is 80 or so. can the pipe take it? could the darts?

second, what is the best way to attach the blowgun? breech loading would be nice but not entirely necessary.

third, which type of valve do you guys think would be better, piston or sprinkler? barrel length will probably be about 3 feet maybe four if the barrel is removable.

Do you suppose you could be MORE specific?

Pipe? What kind of pipe? Copper, aluminum, steel, pvc, or ?

Just remember...PRESSURE RATED or METAL for pneumatics.

Depending on the "pipe" you choose, yes, it'll handle 250psi, or no it won't.

I don't think the darts will have a problem.

Sprinkler valves are NOT rated for 250psi.

Blowguns have threads for a reason. Use them.

A well made piston valve (metal) will easily handle your posted requirements. (I use a copper piston valve @ up to 450psi.)

Do some more research. Check the showcase section for ideas.

by blowgun i meant one of those cheap pieces of aluminum pipe you buy that shoots darts sorry for not making that entirely clear

Check this out then.

http://www.spudfiles.com/forums/blowgun ... 16325.html

If you are too lazy to make your own piston valve, but you do want to use pressures which require metal, consider using a QEV. A commercially made piston valve.

Like the one Psycix has on his cannon but still hasn't shared with the rest of us..

Dude, we need to go plinking one of these days...I restored Overkill..



The darts too should be made out of strong material if they are to survive

nah, i'm probably going to make it a piston valve and as for the darts i'm going to be using a mix of blowgun darts. i was kind of worried about them not being able to take it because in some of the pictures i've seen the plastic cone was half blown forward


so does anyone have any good ideas on how to go about attaching a blowgun to 3/4" pvc pipe? i had been thinking about just wrapping it in tape and jamming it in but at 200psi that's probably just asking for trouble

The ever popular "epoxy" comes to mind.

Much safer than tape at 200psi.

probably

would you suggest any type in particular? i'm pretty much out of the cheap stuff i bought a while ago

My 0.4 barrel is epoxied inside a piece of 1/2 inch PVC. The 1/2 inch PVC is then expoxied inside a copper 3/4 inch male adapter. The tolerances are fairly tight; I had to sand down the PVC to make it fit in the adapter.

Works like a charm

SilentCyan wrote:probably

would you suggest any type in particular? i'm pretty much out of the cheap stuff i bought a while ago

You can't really go wrong with JB weld.( It's just slow as molasses in January to cure!)

Leave it overnight at least, two days to be good and sure.