Semi Auto

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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PCGUY
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Sat Feb 05, 2005 6:39 pm

<div align="center">SEMI AUTO

Provided By - Clide

Deemed the "Slider" gun in reference to it's key part, the exhaust valve.

[youtube][/youtube]

Basically it is a fancy barrel sealing tee valve. The exhaust valve used is a homemade version of McMaster part number 4622K57. In the forward position, the input holes are connected with holes going to the chamber. In the back position, the input holes are isolated and the holes going to the chamber are exhausted to atmosphere. That means input flow is cut off in the same motion that exhaust the pilot chamber. The piston has a built in one way valve for a quick fill without harming performance. If I had a high flow air source available I could get up to .25" input flow, but currently flow is limited by the quick connect fitting. The stock can be pushed into the chamber when the gun is not in use, and I tried my best to give it a fancy paintjob. (3 days ago, waiting 7 days is impossible). I can get about 2 shots off per second. Faster ROF could probably be obtained with an electric 3 way valve instead of the slide valve, but I wanted to stay away from electronics.

Anyway, of course I needed a loading system to keep up with the gun. I decided to use paintballs because they are cheap and fit with the scale of the gun. Seems to work fine. I find paint in there sometimes, but I think it is from the 3 year old paintballs, not a problem with the loading.

Currently I just use a clip, but I am planning on getting a hopper to work.

Provided By - Clide</div>[/youtube]
Attachments
back822.jpg
front822.jpg
grip.jpg
left822.jpg
piston parts.jpg
slide assembled.jpg
slide parts.jpg
slideclosed.jpg
slideopen.jpg
top822.jpg
bolt.jpg
bolt.jpg (10.22 KiB) Viewed 133913 times
noclip.jpg
noclip.jpg (14.5 KiB) Viewed 133912 times
barrel position1.jpg
barrel position2.jpg
barrel position3.jpg
barrel position3.jpg (19.77 KiB) Viewed 133912 times
barreldisassembled.jpg
finalwithclip2.jpg
finalwithclip2.jpg (18.84 KiB) Viewed 133912 times
finalwithclip.jpg
clideauto.gif
clideauto.gif (16.46 KiB) Viewed 133912 times
Last edited by PCGUY on Sat Aug 29, 2009 11:39 pm, edited 12 times in total.
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theexp
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Sun Feb 06, 2005 4:28 pm

BEAUTIFUL. :lol: I love it. I downloaded the vido of it, it is a BEAST. I like how it Killed the sheet metal. Thats awsome. Could you described in a little more detail how it works...

Nice Paint job :D
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syco kilaa
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Mon Feb 21, 2005 10:42 pm

yes could you possibly take some time and MAKE PLANS for it? please????????? I need to make one of these but I'm not really sure what to use for materials, also, about the stock, where is the chamber itself? I mean is the space where the stock comes out of the chamber? help...
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Sun Mar 06, 2005 3:28 am

Sorry, no exact plans. It would take a lot of time and be very difficult for anyone to do without a lathe, but if you have specific questions I can help you out. As for the parts it is pretty much all off the shelf pvc (some modified) except for some PVC rod, a couple springs, some screws, and various rubber sealing parts. Edit, and yes where the extendable stock comes out is the chamber. If I forget to extend it before pressurizing the gun it will kindly remind me by slamming into my gut.

Below is a new animation that includes the bolt and a schematic of the slide valve. They can also be purchased at McMaster, and there are often 1/8" versions on ebay.
Attachments
Each green tic is .25&amp;quot;. Light blue is 1&amp;quot; sch40, red is .5&amp;quot; sch40. Purple is modified 3/4&amp;quot; sch40. Dark blue is PVC rod. Grey dots are holes. Brown are screws. Black dots are o-rings.
Each green tic is .25&quot;. Light blue is 1&quot; sch40, red is .5&quot; sch40. Purple is modified 3/4&quot; sch40. Dark blue is PVC rod. Grey dots are holes. Brown are screws. Black dots are o-rings.
slidevalve.gif (3.09 KiB) Viewed 157690 times
Full animation
Full animation
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theexp
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Wed Mar 09, 2005 7:26 pm

k thats cool, I would probaly get frustrated making it without a lathe, and just light the thing on fire.... :twisted: :evil:
But did you think of it yourself, I LOVE IT
Monkeyd00
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Sun Jun 05, 2005 4:58 pm

Do you have the plans for that loading mechanism?
spudshot
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Mon Jun 06, 2005 6:26 am

you should be able to see how it works from the diagram, and if you need plans for this you shouldnt be building it, espesially since you need a lathe to do it, custom machined parts can blow out on you if you dont know what you're doing
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Monkeyd00
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Mon Jun 06, 2005 4:16 pm

No, I'm just wondering what size pipe/pvc rod he used there. I know what I'm doing, I'm just asking the size of the green piece in the animated diagram of the system.
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Mon Jun 06, 2005 6:07 pm

sorry for the misunderstanding, i thought you wanted like detailed plans for how to make every step, just email him from his address on SGTC forums, i dont think he's registered here
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clide
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Tue Jun 07, 2005 10:10 pm

The bolt is 3/4" CTS CPVC, the tee is 3/4" CTS CPVC, the outermost tube on the loading mechanism is 1" sdr21 I believe, and the threaded fitting that is in the back of it is a machined down 1" NPT x spigot adaptor. Every thing else is just random parts machined down to act like bushings. Whatever I could find to fit. Oh and the spring is from an orbit watermaster sprinkler valve.

Hope that helps
kto
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Thu Jun 23, 2005 9:47 pm

awesome cannon
i like the loading mechanism
Edopsys
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Sun Jul 31, 2005 2:00 pm

How are the oring grooves cut into the slide part of the valve
kudos on the sweet gun. its the only semi ive actually seen a vid for
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Sun Jul 31, 2005 2:21 pm

he used a metal lathe
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deathtodeer666
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Wed Sep 07, 2005 11:23 pm

that is the sweetist thing I have evar seen keep up the good work.
CaptPIKel
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Thu Sep 08, 2005 6:07 pm

I am truly impressed with it. You did a very good job.
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