"Requiem", my first homemade... made from Copper!

[Silence]

Absolutely.

A large stream would definitely be a bruiser at close ranges. The stream speed is going to be about the same, and an even larger stream will just mean more impact force. As the third-to-last image in the SuperCannon II article shows, water cannons would probably hurt a lot.

However, it's probably safe to get hit at the maximum range any water gun can shoot. Water has a low terminal velocity, manifest in raindrops, simply because it's inclined to break up and be subject to more drag force. Therefore it decelerates quickly and doesn't hurt much at a distance, unless there's just so much of it that you collapse under its weight (as in a waterfall or in turbine-powered, water-shooting fire suppressors). Given enough time, the drops will slow down to the point that it feels like rain.

[aEx155]

FYI, you linked to the Supercannon II article, not the SuperCAP. Also, I didn't see any bruising in any of the pictures.

[Drenchenator]

Even though it would be possible, I don't think anyone would be willing to go up against 150 PSI of water pressure. I mean, it's going to hurt, isn't it?

Again that depends. If the stream breaks up a lot, no. It is doesn't, yes. Imagine the stream still has some pressure (dynamic pressure to be precise). If the applied area is larger, it's not going to result in as much force, and from that pain. That's why I was hit by a 130 oz/sec blast from SuperCAP and was fine.

The gun could also just be so inefficient that 150 psi would be like 40 in another. I'm thinking like 5 or more bends before the nozzle with a variety of internal diameters; that's when viscosity is really going to matter.

[aEx155]

Originally Posted by Drenchenator

If the applied area is larger, it's not going to result in as much force, and from that pain. That's why I was hit by a 130 oz/sec blast from SuperCAP and was fine.

That's what I meant. It's like an experiment I saw in my 5th grade science fair:

A balloon was placed in a bucket with a number of nails in the bottom. One nail popped it, several didn't.

I guess what you said makes sense. So as long as the nozzle on any 150 PSI gun isn't too small, then there's no chance for danger.

[Silence]

Sorry, I actually meant to link to the SuperCannon II article. I changed the text.

[Aurum]

Sorry, i havent started building yet, as i cant get to the shops to buy the parts today. My dad blagged my car to go to work in (at 3AM, so i wasnt awake to stop him), and i cant get a lift untill at least 4PM. daaamn.

At least this has given me time to redraw the design plan a bit. We're now looking at "Requiem" version 1.20. Basically, upped the scale of the PC section of the gun. Also, i may go ahead and feature dual PCs now, although this isnt shwon in my plans...



Im still looking for different ideas for the [metal] nozzle, if any one has any?

[Drenchenator]

Well, you can always use hose barbs, like in sbell's APH. Your size selection may be a bit limited, but it's always an option.

You can also just get a male-threaded plug to fit into a female-threaded adapter. Conversely, you can get a female-threaded cap to fit into a male-threaded adapter, like how most homemades on this site have nozzles. If you have a drill available, all you would have to do is drill a hole into the plug or cap for a nozzle.

And McMaster-Carr has plenty of nozzles, but they may just not be in the right sizes. Doesn't hurt to check though.

[aEx155]

I really don't think that the nozzle has to metal; the only pressure it will be holding is the water exiting the stream. Everything from the first check valve up to the ball valve would be under pressure (at some point), while everything outside of that zone wouldn't. That includes the nozzle (to some extent; most argue that it is under pressure).

If the pressure is so high that a plastic nozzle (excluding nozzles made for high pressure) breaks in some way, then it probably will end up hurting someone.

That is, unless, you want to go with all metal just for looks or feel or boasting rights (what about o-rings?)

[Drenchenator]

I was actually talking in general; I wasn't referring to just metal hose barbs, caps, and plugs but hose barbs, caps, and plugs in general. You're right. You can use plastic pieces too if they're available. But I don't think you would have to worry too much about the pressure though, as most of the fittings are rated fairly highly from what I remember.

(what about o-rings?)

If you're thinking about what I'm thinking, I don't think that would work. Just putting an O-ring inside the end of a pipe wouldn't work as a nozzle because it would get blown out once the water's turned on. Are you thinking about something other than this that I'm maybe not thinking about?

[Aurum]

OK, i made it to B&Q before they closed today. Due to out of stock parts, im still missing my 22mm-15mm reducer, and the second check valve is now 22mm (how this will affect the Pressure im not sure, probably not a direct threat though right?)

I even got a [metal] coated 1.5m shower hose to link to the resevoir. not because its metal, just because it was the perfect size (one end is 15mm, the other end is 1/2" although this doesnt matter too much).

Also, big update on my Water Resevoir. Im using an old spraying tank (used with agriculture, for spraying weeds. It has over 16L capacity and already has shoulder handles built into it. To make it work/fit etc, all i have to do is remove the crappy pump (which doesnt work anyway, hence why im allowed to have it), cap the hole where the pump was, remove the pump handle, and drill a 1/2" hole to attach my shower hose to. Apart from that, all i have to do is repair the one strap and give it a good wash to remove the dust/dirt/weed spray remnants.

I HAVE to have large PCs now, with my total water capacity this gun will diserve to have large capacity PCs...

[Silence]

Wow, that'll definitely be a rather large reservoir - about four gallons. It may not be very easy to run around with, but walking should be fine. And as you mentioned, a thorough wash will be necessary...weedkiller isn't a very benign substance.

1.5 meters sounds a little long for the hose. Although I like to err on the side of excess since it's easy to cut plastic tubing down to size, I'm not sure if you can do that with your hose.

[Ben]

Due to out of stock parts, im still missing my 22mm-15mm reducer, and the second check valve is now 22mm (how this will affect the Pressure im not sure, probably not a direct threat though right?)

The size of the check valves does nothing to affect your pressure. It might be marginally harder to open but from what I know they're all calibrated to open at 1 PSI, so it won't be any harder to open.

Also, big update on my Water Resevoir. Im using an old spraying tank (used with agriculture, for spraying weeds. It has over 16L capacity and already has shoulder handles built into it. To make it work/fit etc, all i have to do is remove the crappy pump (which doesnt work anyway, hence why im allowed to have it), cap the hole where the pump was, remove the pump handle, and drill a 1/2" hole to attach my shower hose to. Apart from that, all i have to do is repair the one strap and give it a good wash to remove the dust/dirt/weed spray remnants.

Sounds nice but definitely excessive. You obviously don't need to fill the tank completely to use it. I'd suggest less water in the 8 to 12 liter range, but it's all personal opinion. You might find that you like 16 liters.

Get some pictures up when you finish it or while you're working.

[Aurum]

I'll see what i can do once i've started proper construction, picture-wise.

I know the packet says 1500mm (1.5m) length hose but it honestly doesnt look that long...

[Silence]

I found that it doesn't look that long on the ground, but if you think about the distance from the back of the gun to the backpack when you're actually using the thing, it's surprisingly small. You could probably get away with half a meter of length.

[Drenchenator]

Great idea for the tank! 16L is a lot of water to carry, but who could argue with a tank that comes with build-in shoulder straps? I agree that you should have large PCs now. With that much water available, it would be sad to basically use very little in a full chamber. Good job on the hose too.

I'd like to see some pictures too. Good luck with the build.