which valve

[jon_89]

i have a .5in chamber and a bb barrel. should i use a blowgun or a ball valve? and if a ball valve should i use .5in or a .25in? thanks

[keep_it_real]

considering it's shooting bbs, a blowgun is probably fine. If you do use a ball valve, use a .25 inch one if you can find it. .5 is overkill for bbs.

[frankrede]

a blowgun should work fine, and maybe even better than a ball valve in this situation. unless you have a long barrel.

[paaiyan]

Blowgun sounds pretty good to me.

[jon_89]

i think i will go with the .5in because i will most likly have a .5in barrel also. will this effect the bb barrel any? thanks

[keep_it_real]

No it won't affect it. You won't have any accuracy because ball valves just suck that way.

[paaiyan]

Most likely the torque you put on the device turning the ball valve will bow the weapon and possibly affect the accuracy. Other than that I guess it wouldn't affect performance.

[jon_89]

is there any other way to turn a ball valve other then a spring?

[paaiyan]

You could make a pneumatic actuator for it, though that would be pointless because that actuator would probably be activated by a blowgun, lol.

[jon_89]

is there any way to use a motor? i think this has been brought up before.

[frankrede]

Your cannon is too small for any noticable increase in power, and a blow gun should work just fine for bbs

[integral]

How about a camshaft turned with a ordinary washing motor or some motor similar. It all leads to the size of your project. If you wanted a different valve, why not a small sprinkler (15mm - inches?) actuated via a blowgun...

[frankrede]

OVERKILL!
Come one hes making a bb plinker!
There wouldn't be a noticeable difference if he used a blowgun or a sprinkler valve.
I think at most what he should use is a 1/8" qev, which I think would be the best.
its 5$+5$for blowgun
that setup would be the best

[cyanite]

Umm, I dunno why you would actually bother with a motor, for several reasons;
1- To turn a blow valve you need a bit of power unless you have a really well lubed one
2- A powerful motor would be fairly large, 4 cubic inches or so, where would you mount this?
3- A motor costs a lot more money than a blowgun or even a sprinkler
4- You will be carrying a bunch of wires/ batteries around
5- A motor has a shorter lifetime than a mechanical valve
6- The gears/ belts between the motor and valve would also cost money, and are usually pretty hard to come by for a decent price (here in sydney anyway)

I would suggest a modified blowgun valve, you will have plenty of power for your BB barrel, and you are getting an accuracy advantage over a ball valve. However, a motor would make for an interesting cannon, and if you have experience/ access to them, and you don't mind the extra bulk or inconvinience (S) go for it.