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YASP - Yet Another Stirrup Pump

Built a pneumatic cannon? Then post it here! This section is for completed, finished cannons that you have built. Please include pictures and information.
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YASP - Yet Another Stirrup Pump

Unread postAuthor: dongfang » Sun May 04, 2008 9:34 am

Hi,

Got my pump finished today. Now I can get some decent pressure on my guns...

The pump cylinder is a 72 cm long, 20.6 mm ID, 25 mm OD aluminium tube. I persuaded the plumber next door to try cut a 3/4" pipe thread in it - it then could screw into a 3/4" 'wall angle'.
The piston assembly is a home-made floating O-ring contraption. It is built around a 10 mm bolt, which screws into a bushing that I banged into the piston rod/tube. The piston is a knob / finger screw that I got from the hardware store. It doesn't fit in the tube with nanometer precision, but there is no need for that.
The base/'wall angle' holds the check valve, which is a 1/8" elbow with a screw and an O-ring inside. I connected this to a 3/8" to 1/8" reducer wit some PVC pipe, and screwed that in the base via a 3/4" to 3/8" reducer, Finally, I filled the base with marine epoxy; there is virtually no dead space left.
The piston rod guide on top of the cylinder are plain PVC fittings. The pressure gauge was salvaged from a bicycle pump that broke.

Lubed with a little silicone oil, this thing performs great. All I really need now is a gauge that goes a little higher, and a ditch in which to put my new experimental 16 bar gun, at the other end of my 10 meter long hose. Then, I can pressure test the chamber to 20 bar, hehe.

Feel free to ask any questions. The main features of this thing is that it´s solder free, copper free and epoxy piston free.

Regards
Soren
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Attachments
DSC_0264.JPG
In all its glory. The handle is just 25 mm PVC.
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The handle
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DSC_0267.JPG
The base, with pressure gauge. The black thing is the piston from a pocket bicycle pump. That fits perfectly, too. It just needs to be cut off, and a 4 mm hole be drilled through the bolt.
DSC_0267.JPG (31.44 KiB) Viewed 5333 times
DSC_0160.JPG
Base with check valve installed, ready for epoxy pouring.
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Check valve exploded. The 1/8" elbow just can squeeze into the PVC pipe which is siliconed into the reducers. No epoxy got in...
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DSC_0154.JPG
From another angle.
DSC_0154.JPG (20.07 KiB) Viewed 5333 times
DSC_0151.JPG
Piston ready to go. I dremelled a few grooves in the bolt to make it leakier on the return stroke.
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DSC_0150.JPG
Piston almost-exploded, with a bushing that could just be hammered into the piston tube.
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DSC_0148.JPG
I made the piston out of a knob like this. It is made of very hard (and a little brittle) heat resistant plastic.
DSC_0148.JPG (17.47 KiB) Viewed 5333 times
Last edited by dongfang on Sun May 04, 2008 9:38 am, edited 2 times in total.
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Unread postAuthor: JDP12 » Sun May 04, 2008 9:34 am

looks nice, well done
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Unread postAuthor: Lentamentalisk » Sun May 04, 2008 4:24 pm

Absolutely beautiful! I love your nice compact check valve. What pressures do you think you can take it up to? Good Job!
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Unread postAuthor: dongfang » Sun May 04, 2008 4:41 pm

Hi,

I believe it will go up to where that silly hose ruptures. When I find a replacement for that, it will go up to 25 bar or so. More than that, and I need to find a heavier operator.

The piston area is 3.33 sq cm.

I just used it today; it´s now a breeze to fill my secret prototype cannon to 9 bar. With my old bike pump, you had to like jump on it for the last 20 strokes.

Regards
Soren
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Unread postAuthor: SpudFarm » Sun May 04, 2008 4:50 pm

thats so store bought looking i almost can't say it!!

the metric guys rule :D
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Unread postAuthor: Hawkeye » Sun May 04, 2008 10:02 pm

You could replace the bike pump hose with one of those short sections of high pressure(300psi)hose for preventing hose kink in air tools.
You would need to put one of your little check valves on the gun in place of a schrader.
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Unread postAuthor: Gippeto » Mon May 05, 2008 1:35 am

Very nice pump!

I use hydraulic hose on my stuff. A 3 foot length with 1/4" npt fittings costs 12.00 at the local machine shop. Rated at 5800psi.

Don't forget a bleeder valve between the pump and the gun.

Threaded connections with a check valve on the gun are the way to go.
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Unread postAuthor: watto » Wed May 07, 2008 10:26 pm

nice work, I want one!! where do you get check valves?
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Unread postAuthor: Lentamentalisk » Wed May 07, 2008 10:46 pm

OMFG WATTO! please change you sig and avatar to something less graphic and flashing! I can't concentrate!
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Unread postAuthor: watto » Wed May 07, 2008 11:11 pm

yeah theyre pretty crazy aye, you shoulda seen my other one that PCGUY got me to change :o
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Unread postAuthor: dongfang » Thu May 08, 2008 4:03 am

Hi,

I certainly will take a look at the hydraulic stuff.

And it will be soon, because I am going to make a 14 mm ID version of the same pump now, that will easily give me 50 bar. For materials testing.

Getting check valve is a matter of finding a pneumatic fitting (like a reducer, an elbow or something else), a bolt or similar, and an O-ring that all fit together. But there are many other solutions, too.

A very easy but not at all bed solution is to get a Presta valve (French bicycle tube valve) and glue it into something. I even think you can take the spindle with the rubber seal out of some of them, so you may braze it in without burning it up.

Yeah I am going to add a bleeder valve. Either a ball valve (but they are stinkin' overpriced here) or a home made invention, a little bit like the check valve in the pump, but with the end of the bolt sticking out where I can push it when wanting to take off pressure.

Regards
Soren
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Unread postAuthor: far_cry » Fri Sep 05, 2008 5:16 pm

i get with my pump almost 50 bar
and the diameter of the piston is the same!!! my wight is 92 kg
http://www.spudfiles.com/forums/air-pum ... 15794.html
check out
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Unread postAuthor: Sticky_Tape » Fri Sep 05, 2008 5:30 pm

Pump looks really cool and Far_cry 50 bar is about 735 psi.
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You can tell how awesome a cannon is by the pressure used.
http://www.spudfiles.com/forums/high-pr ... 12803.html
xnt rnm ne z ahtbg
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Unread postAuthor: far_cry » Fri Sep 05, 2008 5:56 pm

Sticky_Tape wrote:Pump looks really cool and Far_cry 50 bar is about 735 psi.

lets say 710 psi
may be my modified check valve let me get that high pressure
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