filling multiple chambers at the same time

[Biopyro]

Plans for water cannon are here. I decided to go to the experts regarding advice, but you can see the more detailed (and neater) plans. I may try to get a rubber bladder tank so that I can get constant pressure instead of having to keep pumping. That would also mean I can pressurise from the municipal water system![/url]

[trollhameran]

the rubber bladder is a good idea, maybe chop up a couple of cheap footballs and take the bladders out of them, perhaps you could make a hole in the bottom for the pipe then put the bladder inside a bottle so that it wont explode if you use to much pressure, that way you can still have the shrader on the bladder for filling it coming out the bottom of the bottle

[THUNDERLORD]

If you slide surgical tubing over a small nozzle fitting for a regular faucet,
And pinch one end, it will inflate with water.
Then pinch the front and remove it from the water supply.
When you release pressure on the front water sprays out.

I bought a toy called a "water weenie" a long time ago. It was a fancy version of that, supposedly invented by a science student because they used to play with water in the college labs.

It had a plastic nozzle tip wire tied onto the front, a plastic clip for the trigger (so it could be stopped) and a rubber stopper piece wire tied at the back.
It also came with a plastic garden hose cap with a little hole in it for refilling it.

It was a cheap fun and clever toy. There are much larger sizes of tubing
out there. Your rubber bladder idea made me remember that one.

I just got a new idea: A piston with o-rings inside a pvc pipe and maybe using rubber tubing for the spring.
Maybe an end cap for the nozzle with a 1/8" hole.
The trigger could work sort of like a caulking gun,
It will press against the rod attached to the piston to stop the water flow temporarily. Just a constant pressure spring piston.

I might build one out of some old pvc I don't trust for pneumatic use and some tubing! 8)

BTW, Biopyro tried to look at your plans but you've got to sign in to see anything there. They've got that sight locked to guests!

[Biopyro]

Ok well cider is the only source of 3l bottles, so I'll have to look into that!
I'm gonna go with just an air pressure design because using rubber tubing is too complicated... for now.
Unfortunately 22mm pipe doesn't fit in the drinks bottle like I thought, so I'm going to heat some flexible hose and fit it around the bottle, hopefully it'll be watertight.

[trollhameran]

try heating the neck of the bottle just enough for it to stretch when you push the pipe into it, thats what i did, either that or file down the inside of the neck a little until the pipe fits, i did that to lol

[Biopyro]

I tried that and I couldn't get the tubing I have to stretch. When I jammed the 22mm pipe in the bottleneck though, it was a perfect fit. I put it up to >100psi and it wouldn't budge on it's own (no swelling or other side effects too). I'll secure it as if it's the male part of a compression fitting, then it'll be no problem.

[trollhameran]

jamming it in was probably the best idea for getting i tight fit and a good seal, thats ideal though that it doesn't leak at all at 100psi

[THUNDERLORD]

@Biopyro, Those plans look great.
You should make a seperate post for that.
There's no showcase for water cannons. Guess it would go in pneumatics if that's allowed(?)

Not to hi-jacking trollhammeran's post, but I was thinking with the garden hose, They thread onto/into 3/4" fittings.
So you could use a repair kit for garden hose(Threaded end piece) to attach the hose, If you use 3/4"
(not sure the metric equivelent). 8)

EDIT: Also I was thinking washing machine hoses are threaded at both ends.

[trollhameran]

Lol i dont mind if my threads hi-jacked, ive got the answer i needed to my question.

Shower hose type thingys (dont think there actually called hoses) the ones with lots of metal rings that bend conecting to the shower head are threaded both ends but they thread onto 15mm fittings as far as i know

[Biopyro]

Hmm washing machine hose is 3/4BSP threads but it may not be long enough - I'l find out.

[trollhameran]

you could always fiz a few pieces together with threaded couplers

[THUNDERLORD]

This topic's a little dead.
But I made a "discovery" today. Not really worthy of a new post and it was mentioned a lot here.

I noticed that the top of a 2-liter soda bottle fits through the hole in 2" inch to 1" inch reducer bushing perfectly!

The threaded part fits through the hole but stops on the lip part.
Then the 2-liter cap can be screwed on holding it in place perfectly!

Probably a rubber washer on each side would be useful and some epoxy on the cap threads to strengthen it.
Then the bushing can be pvc glued into a 2" coupling. The coupling is also a perfect place to mount a shraeder valve. 8)

[trollhameran]

Hmm that is very interesting, ill have to go check that out it makes you wonder if the person who invented the 2 liter bottle was a spudder lol