SpudFiles

Hey everyone, am currently bilding a pnematic spitball cannon, (and piss off everyone in my class ) and was thinking, that maybe i could get one of those pumps in shampoo pump things, and use it to pump up my mini. i think it might work, but can someone tell me why it would or wouldnty work???

it might work but.. ,ud need some kind of check valve in place after the nozzel,for obvious reasons,
if u managed to overcome that id like to see myself what kind of pressure it could reach "give it a go"

It wont work.

They do not have a perfect seal, only enough to pump thick fluids. Added to that, they are only meant to push past a few inches of gravity.

The bore and stroke is also so small that reaching pressures (respectable) would be impossible.

Crap....
then does anyone have an idea of how i could get a small easy pump??

http://www.google.com/imgres?imgurl=htt ... 2&ct=image

and ever thort of using a small bike pump???

Yes, I have, But they are too expensive. i cant find one for under 20$ and wouldnt the pump thing you linked to be too big? i need something small, as in 4-5 cm long at most. any other ideas?

u cant find a basic small hand pump for under $20 can i ask where u have been looking?? if ur an aussie try rebel sport and look for a basket ball pump/ball pump ,i got one from there not long ago its about 200mm long

and the chemical/water pump id say its about 30cm long

and if ur looking for a pump 4-5 cm long let me know cause id like one

hehe lol! actually, i have decided to make my own. it will use some 6 mm copper tube, some small o rings i just found, epoxy and ball bearings. im also gonna have two springs in it, so rather than pumping in\out like a bike pump, it will be more like clicking a mechanicle pencil, only a bit harder. it will be (if my plan works) only 3.5 cm long! yay!

Just checking, you do understand the mechanics of how a pump works, don't you?

this post is not in responce to mr nickname

yeah ive had a stab at making a pump, here she is the chamber is 100mm long except for the handle which is 100mm long as well,, its basically a water pistol i made for my brother,but anyways post some pics once ur completed

hereis a small high pressure pump i made, its pretty easy you just need to make a floating o-ring piston, then you can use a schrader valve as a check valve.