I never played with hydraulics before and I'm after some tips.

I'm thinking about making a height adjustable stool, using hydraulics. Was thinking of making a ram out of pvc pipe and using a garden sprinkler valve to release the pressure(stool goes down). I'm guessing I need some sort of hydraulic pump to raise the stool, anyone know what sort of pump would suit this application? I'm thinking about using just water and would like to find a cheap source for a pump.

Thanks guys...
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Imagination is more important than knowledge. Knowledge is limited. Imagination encircles the world.
Albert Einstein.

Anyone know if this sort of thing would work? Thanks.

http://cgi.ebay.com.au/Chev-V8-High-Volume-Oil-Pump-/260662963024?pt=AU_Car_Parts_Accessories&hash=item3cb0b92b50#ht_500wt_1154
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Imagination is more important than knowledge. Knowledge is limited. Imagination encircles the world.
Albert Einstein.

Not that I am an expert on hydraulics, but you would probably need a high pressure pump, rather than a high volume pump. If you go with water, a pump like that would rust and seize pretty quickly. How about picking up a discarded lift chair and seeing if you can hack the gas strut to work as a hydraulic cylinder?

The ram I'm cool with I can do that myself. If I make a large bore ram the pressure needed would be low but the flow needed would be higher and I guess I could use oil. Thanks for the input.
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Imagination is more important than knowledge. Knowledge is limited. Imagination encircles the world.
Albert Einstein.

How fancy do you want to get? What's your power source?

You could try car power steering pumps, IIRC they will work up to around 500psi and are commonly available.
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https://www.halfdonethings.com/

Not fancy @ all, cheap. Power would be a DC motor from a SLA.
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Imagination is more important than knowledge. Knowledge is limited. Imagination encircles the world.
Albert Einstein.

Car parts always seem to come to the rescue with these budget projects, it's great. I thinking a steering pump or a oil pump could work. I would have to use some type of oil. I guessing the oil pump would be better for a lower pressure application with greater flow as well. A lower pressure system would use cheaper fittings which I like, the bore of the ram would just need to be larger.

I'll try to get some pumps and play with them, thanks ppl.
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Imagination is more important than knowledge. Knowledge is limited. Imagination encircles the world.
Albert Einstein.

Oil pumps run <80PSI 99.999% of the time and will require a fair amount of modification due to their in-motor design. Power steering pumps are sealed units, generally come with reservoirs, lines, fittings (banjo bolts) and rotary valves (from the steering rack) that can all be sources from the car you pinch them off.
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https://www.halfdonethings.com/

Would this be for your flight sim project? If you are going to have a DC motor in there anyway, why not make an actuator from a car scissor jack? Alternatively, you might find a cheap hydraulic bottle jack and motorise that. Car parts to the rescue every time!

Another NEW project Nick

Good tips guys thank you, I'll ditch the oil pump idea.
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Imagination is more important than knowledge. Knowledge is limited. Imagination encircles the world.
Albert Einstein.

Engine oil pumps usually have a fair bit of leakage, no shaft seals, etc.
They're meant to be sitting in the oil reservoir so it doesn't matter


Electric fuel pumps from EFI cars can be pretty good. They won't work with water, but would be ok with kerosene or similar for less flammability.

They'll usually do up to 100psi or so.
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The Engine Whisperer - fixer of things