First attempt at custom soaker.

[Inquisitorphil]

Edit: Note that this is not the latest design: the latest design will be the last one drawn in the topic unless stated otherwise.

Hello SSCentral!

This is my first post here, so please excuse my ineptitude. I've never built a homemade water cannon before, but after my mother decided to throw away two CPS1000s without asking me, I've decided that I won't find that power again without doing it myself.

Below is a slightly rearranged cannon:



1. Would it work in this arrangement?
2. If I'm going for range rather than soaking capacity, should I use a tighter nozzle and wider piping, or a tighter nozzle and narrower piping?
3. Would this format work if I managed to get a rubber air chamber inside the air tank (to mimic CPS technology)?
4. Would a bicycle pump be an alright method for pressurising the cannon? I can't be bothered to faff around with making a custom pump for the moment. For example, this one: http://www.halfords.com/webapp/wcs/stor ... yId_165661 which can get up to 120psi. Or should I go for one which pumps faster but can only get to 50psi?

Thanks in advance!

[BlueCharged]

1) The Air Chamber needs to be put up like in this diagram:

Apart from that it would work

2) Tight nozzle and narrow piping (Im no expert but it seems to work)

3) Yes

4) I would use this for a bike pump http://www.halfords.com/webapp/wcs/stor ... zone=PDPz1

PS: Bike pumps already have a one way valve in so just drill it the hole where the air goes in and put some tubing/piping in there

[Inquisitorphil]

With that in mind, would this work (obviously not with a rubber lining unless I'm really clever):



I'm not 100% clear about what you mean in your postscript though. Could you provide an illustration? I don't get where I'd be putting it to take advantage of its own valve.

Thanks for the help already given though!

[wetmonkey442]

Just remember that you want to keep your trigger valve as close as possible to the bottom of your pressure chamber. In your picture above, you'll end up with quite a bit of water trapped at the bottom. Here's a link to an APH I constructed earlier this summer to get an idea for the parts you need:http://forums.sscentral.org/t6467/

To save parts, you can opt for a straight PC rather than one tilted at 45 degrees. A simple thread male or female on the back-end will serve to attach your water tank.

And I would not recommend using a bike pump. Bike pumps are designed for air not water, and the seals will not handle long-term exposure to moisture. I would recommend building your own pump instead.

[C-A_99]

Perhaps the attached diagram will help.

Wetmonkey, are you sure that bike pump seals deteriorate when exposed to water? They seem to be simply standard O-rings. Plus, I was hoping to find a way to convert bike pumps (particularly foot pumps) to water pumps, which would be easier than building a custom foot pump. (Why a foot pump that pumps water? Well, you could build an excellent turret with such a pump.)

[Inquisitorphil]

Right. Points taken on board. Would the following work?



It's not going to be very ergonomic, but assume I can a) put it together, and b) hold it to work it.

In case it's not clear from the design, the water drains from the tank and is pushed via the pump up through the air tank and drains down into the pipe beneath. This also then compresses the air in the tank.

I believe it's set up correctly so that it would work, but it might not.

Sorry to keep fiddling, but I'm not adept enough to just build and modify until it works. I'd like to know what I'm building *should* work before I try to build it.

[BlueCharged]

It's own valve is in a different place in every different pump. It shouldn't be that difficult to find because it's just a hole.

[C-A_99]

Just remember that the water is ALWAYS level regardless of how the gun is positioned, unless you add a piston to separate the air and water. This applies to BOTH the pressure chamber and reservoir. If your intake (where the water exits the container) is not on the very bottom of the container, you will need an intake tube which is a mess to build and negatively affects performance if you're using an intake tube for the pressure chamber.

Angling the pressure chamber (what you currently have in your latest drawing) has been done a few times, and there are a few good reasons for it, one being that the blaster will often be held up at an angle for longer range shots. Any angle between 0° and 45° will work, but you want to think through how the final product will come out because angled PC's may not be as structurally sound in many cases.

You can take a lot of liberties when designing the reservoir for the sake of ergonomics. You'll just need to build an intake tube as mentioned above, but the improved ergonomics will be worth it. You can also use just about any water container as the reservoir instead of PVC; all that really matters is that the whole thing seals reliably.

You can also use a backpack container as a reservoir, if you wish to do so.

[Inquisitorphil]

Just remember that the water is ALWAYS level regardless of how the gun is positioned, unless you add a piston to separate the air and water. This applies to BOTH the pressure chamber and reservoir. If your intake (where the water exits the container) is not on the very bottom of the container, you will need an intake tube which is a mess to build and negatively affects performance if you're using an intake tube for the pressure chamber.

Yep, the pictures don't really show it, but the exit is supposed to be right against the corner to minimise trapped water at any angle between 0 and 45 degrees.

Angling the pressure chamber (what you currently have in your latest drawing) has been done a few times, and there are a few good reasons for it, one being that the blaster will often be held up at an angle for longer range shots. Any angle between 0° and 45° will work, but you want to think through how the final product will come out because angled PC's may not be as structurally sound in many cases.

I can tighten the structure later, especially when I'm building out of copper. Again, the angle is supposed to help firing at range.

You can take a lot of liberties when designing the reservoir for the sake of ergonomics. You'll just need to build an intake tube as mentioned above, but the improved ergonomics will be worth it. You can also use just about any water container as the reservoir instead of PVC; all that really matters is that the whole thing seals reliably.

You can also use a backpack container as a reservoir, if you wish to do so.

Noted. I'll probably fiddle with the water input after all the rest is together, as it's frankly the least complicated part of the whole design. I will probably just end with a screw-cap so that I can put a platypus or any size standard water bottle on there. It would also make reloading easier.

So, would the latest design work? I don't know whether pumping the water through the pressure chamber is something which has been tried or whether it would work.

[C-A_99]

Not exactly sure what you're asking, my guess is that it's regards to the water source of the pressure chamber coming in from in front of the PC instead of from behind it, i.e. as the water is shot out, the water will go past where the water comes in from pumping.

This is actually how all CPS's work, as far as I'm aware. The bladder (pressure chamber) goes behind where the water comes in from the pump and the water is shot past it when the valve is opened and shooting.

From what I know, that setup introduces a negligible disturbance on stream performance, that is, it theoretically reduces performance by an insignificant amount. In practice, it doesn't matter at all and will work fine.

[Inquisitorphil]

Excellent. I shall go to Screwfix tomorrow and build it after work. You will know the results in a day or so when it's all stuck together. Fingers crossed!

[atvan]

If you plan to convert the design to CPS, you must drill holes in the PC container, where the rubber tube/bladder is. Otherwise it will act funny.

Also, the pump would need to be reduced in size.