400psi pumping effort

[josephlys]

If I were to use one of those mountain bike shock pumps to pump up my air-chamber. How much effort would it take to pump it up to 300-400psi? Do I really need to be strong? Is it a work out when it starts reaching the high pressures?

[MrCrowley]

How long is a piece of string?

We need more information. You're pretty much asking "how long does it take to drive to New York? Do I need a lot of petrol?".

[cammyd32]

Well it depends on how big your pump is. The smaller it is the easier it is to pump due to the equation for pressure and force relating to a piston. A good pump that I personally have had no trouble getting up to 400 psi like this one: http://www.ebay.co.uk/itm/Raleigh-MTB-M ... 2099wt_992 Is both cheap, and for smaller chamber sizes great as it doesn't take much effort to crank it up to 400.
But if you want to fill your chamber a lot faster with a pump with a bigger volume then it will probably start getting hard for your average fella' at around 300.

TLDR version: NO

[jackssmirkingrevenge]

Pumping more than a couple of cubic inches does get a bit annoying, even after modifying the pump for comfort.



Think about getting a fridge compressor. It's not as portable, but will take a small chamber to 500 psi plus in a very short time.

[josephlys]

Yeah I was looking to get that sort of pump. My chamber is 1/2''x8'' I think it's 35cm3. Is the difference of 100psi and 300psi huge in the same chamber. How much more power do you guy experience?

[jackssmirkingrevenge]

force = pressure x area, so three times the pressure gives you (roughly!) three times the force.

1.6 cubic inches isn't *so* bad but it will still get annoying, a couple of shots at 400 psi and you'll be looking for a scrapped fridge

[POLAND_SPUD]

get a fridge compressor for god's sake

[Fnord]

For a portable solution, you could also build a stirrup pump for probably under $30. Some copper tubing, threaded rod, nuts/washers and a check valve will get you most of the way there.
You'll be able to put 400 psi in such a chamber in probably ten seconds or less.

[jackssmirkingrevenge]

For a portable solution, you could also build a stirrup pump for probably under $30.

Hear hear.

http://www.spudfiles.com/forums/easy-st ... 13277.html

Some other useful links here: http://www.spudfiles.com/forums/high-pr ... 24224.html

[josephlys]

I'll be sure to look into that. Is a stirrup-pump better thank a bike shock-pump? Easier to pump to high psi?

[jackssmirkingrevenge]

Is a stirrup-pump better thank a bike shock-pump? Easier to pump to high psi?

Definitely. A shock pump is made for... well, shocks, and these are low volume devices that do not need regular pumping, and the pump needs to be portable.

If you look at an airgun pump:



It has a longer stroke and allows you to use your upper body weight to push down on the handle, much more comfortable and allows you to get up to the 3000 psi range.

If you have $200 to spare, why not.

With the links above you can build your own with relative ease and much less cash though.

[josephlys]

Just curios what does the red button do on the shock pump.

[jackssmirkingrevenge]

It kills an orphan in the third world.

Mine is stuck :-/

It's a bleed valve, in case you pump it up too high and want to turn it down a bit.

[al-xg]

A decent track pump for bicycles can produce 400psi (or slightly more) as long as it is made from half decent materials (or if parts can be replaced for sturdier ones), and it will do this a lot faster than a tiny shock pump.