John Daly

Show us your pneumatic spud gun! Discuss pneumatic (compressed gas) powered potato guns and related accessories. Valve types, actuation, pipe, materials, fittings, compressors, safety, gas choices, and more.
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D_Hall
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Mon Feb 01, 2010 8:54 pm

A big heavy guy who can send golf balls out some distance.

Figured I'd finally follow up on what I did with the sch 10 stainless pipe I bought last year. This is it. The design really isn't that optimum for performance. In fact, it's not particularly impressive. But the gun shoulders nicely and is easy to aim given the limited accurate range of golf balls (SLICE!).

In any event....

Barrel: 6' of 1.5" sch 10 stainless steel sleaved inside 6" of 2" sch 80 to provide an easy way to connect it to the valve.
Valve: 1.5" Asco pulse valve.
Pressure: I've had it to 150 psi. No real intention of going higher.
Velocity: 600 fps (measured with commercial chrony).

Image


Here we have a close up of the trigger/safety assembly. 'Tis the only part of the gun that is (IMO) clever in any way. As you can see I fed the vent through the chamber. This makes for a clean mounting for the trigger.
Image

And here is a sequence of pics to show the loading sequence. It goes pretty quick and easy.
Image
Simulation geek (GGDT / HGDT) and designer of Vera.
John Conklin
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Mon Feb 01, 2010 10:24 pm

I like the innovative design. Especially the trigger mounting system and the O-ring seal on the barrel.
Clearly you have considerable metal working experience under your belt.
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McCoytheGreater
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Mon Feb 01, 2010 10:27 pm

Neat looking gun. I like the way you integrated the shoulder mount and front grip into extra chamber space. Not only that, but the way the trigger is piped through the chamber is pretty nifty as well. It seems that everything in the gun is very clean and straight. Nothing hanging out to the sides. Tell me about that pulse valve.
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POLAND_SPUD
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Mon Feb 01, 2010 10:56 pm

I could swear I've seen it before
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D_Hall
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Mon Feb 01, 2010 11:02 pm

John Conklin wrote:I like the innovative design. Especially the trigger mounting system and the O-ring seal on the barrel.
Thanks. As I said though, the only thing in the design that I consider at all clever was the trigger mount. Everything else has been done by somebody else somewhere before (and heck, probably even the trigger mount but since I don't know of anyone else I'll claim independent invention). :)
Clearly you have considerable metal working experience under your belt.
Not at all.... I just owe a case of beer to a guy who does. ;)

McCoytheGreater wrote:It seems that everything in the gun is very clean and straight. Nothing hanging out to the sides. Tell me about that pulse valve.
I will not build a gun if it is anything but clean. A kludged design isn't worthy of the time/effort it takes to build it IMHO.

As for the valve, it's one of these... http://www.ascovalve.com/Common/PDFFile ... nPulse.pdf

POLAND_SPUD wrote:I could swear I've seen it before
You have. Sort of. A while back somebody asked a question about something and I posted a pic of the gun in response. But the gun wasn't 100% finished yet so I don't really count that.

Ah... Here's the pic I posted previously (see below). Notice that the trigger/forward grip positioning/etc. changed by final revision.
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tghhs
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Tue Feb 02, 2010 12:06 am

Moddled in GGDT? :P haha

EDIT: I love the gun too, nice and neat just the way i like it.
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jackssmirkingrevenge
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Tue Feb 02, 2010 12:12 am

I've had it to 150 psi. No real intention of going higher.
Shame, given the overengineered construction.
hectmarr wrote:You have to make many weapons, because this field is long and short life
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D_Hall
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Tue Feb 02, 2010 12:43 am

tghhs wrote:Moddled in GGDT? :P haha
Yes, actually.

It was actually kind of funny. When we took it out for it's first shots I told my friends that it should shoot at about 600 fps. I found out later they thought I was full of crap, so you can imagine their reaction when the first measured shot was at 593 fps. 8)
Simulation geek (GGDT / HGDT) and designer of Vera.
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McCoytheGreater
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Tue Feb 02, 2010 2:18 am

You really get a scale for the project in the pic. I like how the barrel is almost eye-high. I don't know if that was the original plan, but it looks like it would make for easier target acquisition. Nice looking gun. Congratulations on a successful build.
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tghhs
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Tue Feb 02, 2010 4:35 am

D_Hall wrote:
tghhs wrote:Moddled in GGDT? :P haha
Yes, actually.

It was actually kind of funny. When we took it out for it's first shots I told my friends that it should shoot at about 600 fps. I found out later they thought I was full of crap, so you can imagine their reaction when the first measured shot was at 593 fps. 8)
Nice, that is pretty awesome.
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POLAND_SPUD
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Tue Feb 02, 2010 6:02 am

Here's the pic I posted previously
ohh yeah I remember now.

Have you launched something heavier than golf balls with it ?
I wonder what recoil you could get with steel ball bearings :D
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deathbyDWV
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Tue Feb 02, 2010 8:57 am

Nice cannon. Where did you get the valve at?
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dewey-1
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Tue Feb 02, 2010 9:15 am

@D_Hall

Great to see your 1.5 Asco launcher completed!

Could you post a screen shot of your GGDT parameters for this valve?

I would like to compare to my Asco parameters. I too bought two of those valves back awhile.
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john bunsenburner
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Tue Feb 02, 2010 11:24 am

Nice, the gun looks a lot more impressive when you are holding it! How about a paint job?

Also, what does this baby weigh?
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D_Hall
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Tue Feb 02, 2010 11:54 am

Dunno that I'll bother with a paint job. Now that it's up and running I'll probably disect it for parts and start on a different project (depends on whether or not I can find a 3" pulse valve for a reasonable price).

Weight? Yeah, it's heavy; thus the name! But if you want a number... I'll say it's on the order of 20 pounds. Really no big deal when it's sitting on your shoulder.
Simulation geek (GGDT / HGDT) and designer of Vera.
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