British newbie seeking more power

[Silence]

You probably do a straight part after the cone, although commercial water guns seem to make do with nothing. Regardless, the straight part is where the straws should be.

I believe somebody tried using coffee stirrers, but it didn't work all too well.

[Biopyro]

I must say, the instructable progress ground to a halt when I realised that there was almost no need for the handset I had made. I guess now it will just be easier to make the instructable because there will be less steps. I might put in a bit about making the laminator (with credit) if that works too.

This is the Instructable so far, I think you can view it even though it isn't published.

I may go for a 1/4 nozzle if I can, snce 800ml/s is what I get now I think?
If the volume is 4l, and it vents in about 4 seconds.

[Silence]

It's neat that you can look at unfinished Instructables, although maybe it's only limited to registered members. The guide's looking good so far.

Those who use PVC should still use pressure-rated pipe.

I'm getting question mark glyphs where there should be pound or Euro symbols. I'm not sure if it's my computer or not...I'm pretty sure Unicode works fine on this end, at least with most fonts. Weird.

800 mL/s is 27 oz/s, or 27X in water gun terms. That's pretty high, as even the CPS 2000 maxxed out below that, and it's close enough that the numbers are probably right. And it's even better considering it's using just hose pressure. But 4L in 4 seconds is 1000 mL/s, so it could be even better...I'm not sure which it is though.

What nozzle size are you using right now? And what's the approximate inner diameter of the hose barbs (since those will kinda limit the flow through large nozzles)? I'd say a 1/4" is best, but don't rule out 5/16" or 3/8". Ultimately you'll want to test out different sizes to find the sweet spot.

[Biopyro]

Well, I tested the tank today, and it turns out that at 20psi it holds 3l, and at 30bar (what I got that stream at) 2.3l, so a little dissapointing there! I really want to upgrade the tank to an 18l, but it's £22 I don't have .
At the moment I am firing straight out of the 3/4" ball valve (~20mm opening). I am perfectly happy with the flow I get from my CPS 1200, 141 mL/sec (4.7 oz./sec), infact, the original plan for this project was to have a CPS 1200 which didn't need refilling or pumping! What sort of nozzle would I need to get 150ml/s?

The thing with the pound symbols is a problem with instructables, and happens unless I save in a certain way. It's a pain, but I will fix it for the final version

[Ben]

Yes, I think that it's important to note that while the pressures are lower than typical spud gun pressures (and some water guns don't involve any gas, which essentially makes catastrophic failure impossible), that's no excuse to not use pressure rated pipe and fittings. Parts shearing off that causes part of the water gun to turn into a water rocket are what you should worry about primarily.

@Silence: I think he's referring to my flow approximation on the previous page about the 800 mL/s.

1/4 inch would have lower water flow than 3/8 inch because it is smaller. From the approximation I used earlier, you should expect about 350 mL/s of flow.

Let me note that this approximation is bound to be wrong in most cases because I based it on a very small amount of data. So just take it as a guess. Simple but more accurate flow approximations would have to use flow coefficients for the accumulator tank, the hose, the ball valve, and the nozzle. Such data for general parts is a little hard to come by but I've been compiling it recently.

[Biopyro]

Just wondering if there is any point in trying to make a laminator for flow out of a nozzle as small as 1/4"? I guess I could always have the 2 laminators in series, or just screw a 3/4" to 1/4" adapter onto the riot blast laminator.

[Ben]

1/4 inch isn't that small of a nozzle, so you could see a benefit. Try out some laminators and see if it makes a difference. Often they won't help and often they will. The only way to know aside from CFD (computer modeling) is through testing.

There aren't any general rules for laminators aside from that small diameter pipes (like 1/4 inch or smaller) shouldn't use them because a pipe that small essentially is a laminator.