Semi Auto

[PVC Arsenal 17]

The slide valve you selected is male x female. Depending on which end is male, you may not even need that 1/8" nipple you have.

And if you're still confused about the function of a slide valve... read the item notes in the link you provided.

"The Slide Valve allows easy isolation of down line components. In the "ON" or "Open" position system pressure flows from the inlet through a series of radial holes in the body to the air circuit. Moving the sleeve to the "OFF" or "Closed" position air from the circuit will flow through the body and exhaust to atmosphere "

[Lockednloaded]

ok thanks for that, just a careless mistake, i removed the nipple. the 1/8 schreader from spudtech will be screwed into the other side of the valve. I know the function of a slide valve after looking at your diagram, thanks.

[PVC Arsenal 17]

ok thanks for that, just a careless mistake, i removed the nipple. the 1/8 schreader from spudtech will be screwed into the other side of the valve. I know the function of a slide valve after looking at your diagram, thanks.

Schrader valve? Why? That makes it a b!tch to supply the gun with constant air. If you're going to fill your gun up from an external source, disconnect it from that source, and then go and fire, you're wasting your time and money with a slide valve when a simple blowgun or ball valve would suffice.

If you DO intend to connect your gun to a constant air source, I would suggest using something more convenient... such as a quick disconnect coupling. That would also offer a MUCH higher flow rate which you'll need if you plan to fire your gun fast.

[Lockednloaded]

do i need constant air, or can i just have a large chamber. I want this to be a gun that i pump up than take like six shots before i fill it up again

[PVC Arsenal 17]

do i need constant air, or can i just have a large chamber. I want this to be a gun that i pump up than take like six shots before i fill it up again

Oh that's right, I forgot you had mentioned that... Well in that case, you don't NEED constant air. It would just make it easier to achieve consistent shots. Unless you're ready to have a large chamber (possibly with a regulator so that you CAN achieve consistent shots) constant air seems like a good idea. A simple regulated CO2 rig isn't hard to do, and you wouldn't be limited to just six shots.

If you do want to go with an onboard tank, take some time to read about btrettel's FANG 2 project. Some very good ideas for that on there.

[Lockednloaded]

so are you saying i put a regulator between the chamber and QEV, if so, how would i go about doing this?
And if i wanted to supply constant flow to a schreader, could i use one of these? Click Me
PS-don't have the money for a Co2 reg right now

[PVC Arsenal 17]

Try to do some research. Here is an example: http://trettel.org/blog/35

Yes, you could use that air chuck to supply constant air to a schrader but it'd be an ugly looking extremely ghetto setup. You'd be much better off with a quick disconnect coupling.

[Lockednloaded]

hmmmm... regulators seem expensive and complicated, would performance be too inconsistent without one?

[PVC Arsenal 17]

Spud guns with onboard multiple-shot tanks have been done many times before. Do a search and see what you can find.

[Lockednloaded]

spudguns with on board multi shot tanks are fun for sprinkler valve cannons and such, but are they really necessary? In This example he doesn't need a regulator, the chamber is charged and then he gets lots of shots out of it. Is there something I am missing?

[POLAND_SPUD]

What about these toggle valves for filling/piloting

forget about them... first of all, 39$ for that thing is way too much... secondly it must have low flow..

a smaller QEV to help vent the main QEV

it does make sense as you get 4 things at the same time:

1. a 1/8" QEV will outperform any 1/8" DCV as far as flow is concerned
2. you achieve more consistent opening times of the pilot valve (in this case the aux. QEV) so in other words it becomes less improtant to open the main 'trigger' valve fast
3. you can use smaller 'trigger valves'
4. you can put your 'trigger valve' anywhere on the gun without noticable lowering performance

@pvc

the Clippard MJVO-3

it's a poppet valve right?? how hard you have to press teh stem or the lever to open it at, let say 500 psi ? how high pressures have you used with it ??

The "open" part is very important

that's what I don't like on their valves... but still you could build a gun with an NC valve... they would be safer than those with NO valves as first you would have to press the 'trigger' to fill the gun and it will fire on depressing it

I think I've found something that can handle high pressures well
bosh rexroth 0820402002

[btrettel]

Lockednloaded, if you don't use a regulator, you'll find that performance will drop. You might be able to only get a few shots out without a regulator before the performance drops too much. Regulators also aren't much more expensive than the other components mentioned here. I suggest using one unless you're very cheap and/or are willing to pump between shots.

[Lockednloaded]

I see.... regulators seem like alot of extra parts, you are all experts on this field as i already know, but i think you are thinking a little too hard for my skills and budget

performance will drop very quickly after the first few shots.

This isn't a highly efficient extremely well studied gun, it is my first venture into the world of semi-automatic spudding. This seems like a great approach to this for me, I am asking how well this will work with the parts i have gotten. Your ideas are great and will definitely be implemented further down the road when i am comfortable with this subject (I'm using threaded parts) I just really need to know this: with a QEV+slide valve+large chamber can i pump this cannon up and get a few good shots out of it?

[btrettel]

The page you've linked to is not a gun with an onboard gas source. It has a fill nipple connected to the slide valve. I assume they attach a source there. In this configuration the regulator could be attached to the gas source. Unfortunately, the connection is not visible in the video, so I have no idea what type of source they use.

Also, if the source is large enough, a regulator is not necessary as the pressure won't drop too much.

You might confuse the gas chamber connected to the outlet side of the QEV with the gas source. The two are separate. The outlet side of the QEV is what is exhausted each shot. The gas chamber attached to the inlet is what fills the outlet side.

[Lockednloaded]

thank you very much that was exactly what I was looking for. I assume i can either have a low pressure large chamber or a high pressure smaller chamber, or even the median of the two. You have helped me alot along with PVC and POLAND. I will now try to get the money to build this thing