SpudFiles

I built my first potato gun two years back using a 3/4in sprinkler valve. It sure is fun as hell and impresses friends and family members entertaining our summer picnics for hours. I live in SE MN and have a 12 acre wooded lot and have a large air compressor with plenty of hose to pull to the back yard.

One thing that constantly teases me is the quest for more power. I've been trying to find sprinkler valves with a larger diameter or putting a couple of smaller 3/4 valves in parallel in the hopes of more air and more volume to really punch that potato to the max.

I just joined the forum today to hopefully find some good direction to build my next one but i'm just more confused. People mention that the sprinkler valve is a great starter gun. What would people suggest for my next build to achieve more power?

I do have a full wood working shop, tools, and i'm pretty damn handy so complexity of the build isn't a big issue for me.

i'll continue on the searching through the forums but some suggestions would be great as well.

Thanks

In the corner of your screen you'll see a number of buttons.
home-forum-cannons etc.

click "wiki"
It's our Bible.

There are several big valves you could make.
A piston valve is probably the easiest.
Look it up.

Here's a shortcut:
http://www.spudfiles.com/spud_wiki/inde ... ory:Valves

If ultimate power from a pneumatic is what you seek, look into burst disk valves.

Brian the brain wrote: There are several big valves you could make.
A piston valve is probably the easiest.
Look it up.
title=Category:Valves

maybe i should clarify my question/confusion.

In my mind there are factors that would define the muzzle velocity of a spud. PSI along with the restriction of compressed air leaving the air chamber to the back of the potato.

(off the top of my head) I have a 4 inch diameter air chamber that is filled to 125psi, then it's reduced to the 3/4inch sprinkler valve, then has to expand again to the 2 inch diameter barrel that holds the spud.

I'm guessing that if i didn't have to reduce the pipe all the way down to 3/4 inch then the air could be released much faster giving me a higher velocity. Are there other factors that i'm overlooking? I don't care about how easy it is to make i'm just looking for insight on what can simply give me higher velocity.

I will check more in that Wiki link, thanks brian.

A valve performs better the faster it opens, and the less restricted it is. A burst disk is the ultimate solution, this is how you go about it:

Connect your barrel to your chamber with one of these:



block off the coupling with layers of material (for example heavy duty aluminium foil) that will fail at 125 psi.

Fill your chamber until the material fails, and *whoomph*

You have the equivalent of a valve with no flow restriction, and zero opening time.

I live in SE MN and have a 12 acre wooded lot

I got a 12 metre long basement, nosy neighbors and a police station across the street

Kilash wrote:I got a 12 metre long basement, nosy neighbors and a police station across the street

That would explain your recent interest in "captive piston" devices...

Kilash wrote:I got a 12 metre long basement, nosy neighbors and a police station across the street

That just makes it all that more fun !

jackssmirkingrevenge wrote:If ultimate power from a pneumatic is what you seek, look into burst disk valves.

I'm guessing with those burst disk valves that you can't really control when it goes off?
I do like having the simplicity of a a trigger.

here correct me again if i'm wrong.

I'm seeing that a piston valve or a dust collector valve would give me a much better performance than the sprinkler valve.

izod wrote:I'm guessing with those burst disk valves that you can't really control when it goes off?
I do like having the simplicity of a a trigger.

The system I described should fire within 5 seconds of you starting to fill assuming you're filling from a compressor.

You can also make a triggered burst disk: http://www.spudfiles.com/spud_wiki/inde ... burst_disk

This is a bit more complicated to set up, but it has been done: http://www.spudfiles.com/forums/trigger ... 24868.html

I'm seeing that a piston valve or a dust collector valve would give me a much better performance than the sprinkler valve.

Dust collector valves and sprinkler valves are similar in construction and for the same diameter and piloting will give similar performance.

A piston valve works on the same principle, but due to the nature of its configuration it can allow for greater flow.

For minimum effort, buy yourself a 2" sprinkler valve, convert it to manual piloting and you're sailing.

For such a large valve, something like a 1/2" ball valve is a better idea for a pilot than a blowgun.

Three words for you..... Dust collector valve......
@ jsr my 1 1/2 inch dust collector out performs my 2 inch sprinkler valve... Not even close to the same performance...

mattyzip77 wrote:@ jsr my 1 1/2 inch dust collector out performs my 2 inch sprinkler valve... Not even close to the same performance...

Did you try them side by side with the same chamber, barrel, pressure and pilot? Perhaps the dust collectors have smaller pilot areas and greater diaphragm travel.

Yes sir same everything....The dust collector has its own built in pilot allowing a faster opening time...

mattyzip77 wrote:my 1 1/2 inch dust collector out performs my 2 inch sprinkler valve... Not even close to the same performance...

So Matt, with the dust collector valves... you say they open faster than the sprinkler valve, Is that the main difference? Do you know if the diaphragms in those open up further as well, to allow for greater volume?

I've noticed most people who are using these valves seem to be using them with golf balls and a lower psi. As much fun as it would be to launch golf balls, i don't want them all over my woods. From your testimony, I'm guessing the dust collector valve should still be better than sprinkler valves for potatoes as well?

My current gun with the 3/4" sprinkler valve is pumped up to 120psi. Do you have any experience with dust collector valves and high psi?

Did you still have a couple for sale?