YASP - Yet Another Stirrup Pump

Cannons powered by pneumatic pressure (compressed gas) using a valve or other release.
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dongfang
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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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I made the piston out of a knob like this. It is made of very hard (and a little brittle) heat resistant plastic.
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 9152 times
Piston almost-exploded, with a bushing that could just be hammered into the piston tube.
Piston almost-exploded, with a bushing that could just be hammered into the piston tube.
DSC_0150.JPG (24.3 KiB) Viewed 9152 times
Piston ready to go. I dremelled a few grooves in the bolt to make it leakier on the return stroke.
Piston ready to go. I dremelled a few grooves in the bolt to make it leakier on the return stroke.
DSC_0151.JPG (21.52 KiB) Viewed 9152 times
From another angle.
From another angle.
DSC_0154.JPG (20.07 KiB) Viewed 9152 times
Check valve exploded. The 1/8" elbow just can squeeze into the PVC pipe which is siliconed into the reducers. No epoxy got in...
Check valve exploded. The 1/8" elbow just can squeeze into the PVC pipe which is siliconed into the reducers. No epoxy got in...
DSC_0155.JPG (34.27 KiB) Viewed 9152 times
Base with check valve installed, ready for epoxy pouring.
Base with check valve installed, ready for epoxy pouring.
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.
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 9152 times
The handle
The handle
DSC_0275.JPG (28.83 KiB) Viewed 9152 times
In all its glory. The handle is just 25 mm PVC.
In all its glory. The handle is just 25 mm PVC.
Last edited by dongfang on Sun May 04, 2008 9:38 am, edited 2 times in total.
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JDP12
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looks nice, well done
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Lentamentalisk
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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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dongfang
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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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SpudFarm
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thats so store bought looking i almost can't say it!!

the metric guys rule :D
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Hawkeye
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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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Gippeto
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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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watto
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nice work, I want one!! where do you get check valves?
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Lentamentalisk
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OMFG WATTO! please change you sig and avatar to something less graphic and flashing! I can't concentrate!
Do not look back, and grieve over the past, for it is gone;
Do not be troubled about the future, for it has not yet come;
Live life in the present, and make it so beautiful that it will be worth remembering.
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watto
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yeah theyre pretty crazy aye, you shoulda seen my other one that PCGUY got me to change :o
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dongfang
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Location: Switzerland

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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far_cry
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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
ImageImage
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Sticky_Tape
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Pump looks really cool and Far_cry 50 bar is about 735 psi.
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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far_cry
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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
ImageImage
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