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

Homemade water gun threads that are notable.
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SSCBen
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Re: "Requiem", my first homemade... made from Copper!

Post by SSCBen » Sun Jun 22, 2008 2:52 am

Aurum wrote:BTW
Im going to experiment with an accidentle nozzle i found. Some bags of water baloons come with a cheap plastic nozzle right? the ones i bought recently had one, with a threaded nozzle! and its roughly 22mm inside, and fits directly (well, with a little bodging) onto my Release valve. i think the nozzle's hole is about 5 or 6 mm wide, but ive still got my blanking disc ill drill to 4mm otherwise
I missed this for some reason.

I've seen what you're talking about before. They should work fine as nozzles. They even have a conical part so they're a little better than straight caps or blanking discs.

Let us know how well the gun works. Sounds like you have it done.
devvo wrote:in my third year at college doing heating and vent we had finished all our coursework a few months early so we could do what we wanted so we built our own, thats why i bring up the expansion vessel, you get them from 500ml to massive 100L ones, in our class of 30 we built 6 silly powerful guns, one guy had a 12L expansion vessel strapped to his back which he charged up to 12 bar with a motorised test pump, with a 28mm barrel he blew everyone away, of course not everyone has free materials like we did, i just wish we could of kept them but the college wouldn't let us run off with hundereds of pounds of fittings!
12 bar (about 175 PSI for those who don't know) is pretty high pressure so I'd imagine it would be incredibly effective at dishing out water. It's really too bad that you guys couldn't keep your creations but given their price I don't blame the college. I wish I had access to stuff like that... maybe I should get a job working for a plumber. :)

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Drenchenator
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Re: "Requiem", my first homemade... made from Copper!

Post by Drenchenator » Mon Jun 23, 2008 1:33 pm

in my third year at college doing heating and vent we had finished all our coursework a few months early so we could do what we wanted so we built our own, thats why i bring up the expansion vessel, you get them from 500ml to massive 100L ones, in our class of 30 we built 6 silly powerful guns, one guy had a 12L expansion vessel strapped to his back which he charged up to 12 bar with a motorised test pump, with a 28mm barrel he blew everyone away, of course not everyone has free materials like we did, i just wish we could of kept them but the college wouldn't let us run off with hundereds of pounds of fittings!
Sounds awesome! Do you know the flow rate or range those got?
The Drenchenator, also known as Lt. Col. Drench.

devvo
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Re: "Requiem", my first homemade... made from Copper!

Post by devvo » Mon Jun 23, 2008 5:12 pm

we had massive range, the guy with the 12L expansion backpack made his barrel 28mm got quite decent range of about 15 meters, my own was a little different in that I wanted a good blast with serious range so in order to have the pressure high enough I used two 3L high pressure expansion vessles and a high pressure braided hose with 18mm carbon steel pipe for the barrel and a female threaded coupling on the end so i could change the diamater of the barrel by changeing the endcap. I charged it up with the test pump to 20bar!

I also used half of a 4 inch clip for a shoulder stock which you really needed cuz the recoil was a biatch. it could shoot around 25-30 meters and was a hell of a lot of fun (but not for the joiners and painters haveing a smoke outside there building opposit us LOL)

aEx155
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Re: "Requiem", my first homemade... made from Copper!

Post by aEx155 » Mon Jun 23, 2008 5:17 pm

What do you mean by barrel? Is the the nozzle size? Also, what did you guys use for triggers? Ball valves?

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SSCBen
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Re: "Requiem", my first homemade... made from Copper!

Post by SSCBen » Mon Jun 23, 2008 5:44 pm

Wow. That beats what I've done, though I've limited myself to 100 PSI, not 20 bar. You should improve your efficiency if you use a conical nozzle. I'd imagine you could increase your range by maybe two or three meters if you do that, which should give you at least 85 feet of range easily.

Do you have any photos?

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Silence
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Re: "Requiem", my first homemade... made from Copper!

Post by Silence » Mon Jun 23, 2008 5:48 pm

The "barrel" is just the tubing that leads to the nozzle.

30 meters of range? Wow. What size nozzle did you use? (As you know, the recoil force would be be 20 bar, or ~300 PSI, times the cross-sectional are of the nozzle. At that pressure, you'd have a lot of kick regardless of what nozzle you use.)

devvo
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Re: "Requiem", my first homemade... made from Copper!

Post by devvo » Mon Jun 23, 2008 9:38 pm

As I said I used a female threaded coupling at the end so I could change the nozzle, the plan was to experiment with various fittings and sizes finding what was the most effective bore, hovever as soon as I was finished I was quite happy with full bore 18mm, the problem of course you would have about 20 seconds of charge before it ran dry, we had 2 motorised test pumps that could fill and pressurise the system in 30 seconds but even then we where running out so fast we couldnt really have a war (then again at them pressures someone would probably of lost an eye!).

for the triggers we mostly used ball valves but one guy had a great one, he used a pressure blowoff valve, tightened the springs so it wouldnt blow at the high pressure he was using and had the blowoff lever where the trigger would naturaly be so he would just press the lever light and BANG.

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Aurum
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Re: "Requiem", my first homemade... made from Copper!

Post by Aurum » Wed Jun 25, 2008 12:06 am

I know its been a while (over a week and a bit) but things are going so-so

The cork idea failed. it was ok, but... well trust me it didnt work. Next i tried super-gluing diphrapm seals onto a a wooden pole (after trimming the slightly. This was my best pump yet- fully water tight, up untill certain pressures when the pump could not long force the water BACK into the PC. the pressure int he PC was too great, and the water forced itself past the rubber seal in the pump.

At this point, ive now updated my pump shaft from 20cm of 15mm, to a (220% more volume) 30cm of 22mm. i tried with rubber seals again. No luck, i can only achive about 2/5 of full capacity (so about ~0.5L being compressed about ~0.3L)

---Not perfect, but at this point without a nozzle (firing from the 22mm piping nozzle) i can get the water to travel about 20 feet, in a large burst of water lasting less than 1 second
---But with the lucky nozzle i found (which is about 6mm) i can get te water to travel about 25-30 feet, in a jet lasting about 2 seconds. Both nozzles were tested at just above the horizontal (so 20-30* )

BTW
Im now using the pump from a feeding sringe (also agricultural, like the resevoir). slightly tight fit, but more water tight than the rubber diaphrapm seals.

I'll be testing tomorrow, but that will be it for 2 weeks. Im off to the USA state of Florida for a holiday. Woo! Sunshine!
Armoury includes: Homemade Copper Gun, "Requiem" (boasts a very large water-carrying capacity, large pressure chamber, fitted pressure gauge, and as of 2nd Sept 2011, fully working home-made pump)
I seem to literally only log in once a year!

aEx155
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Re: "Requiem", my first homemade... made from Copper!

Post by aEx155 » Wed Jun 25, 2008 12:32 am

Too bad about the cork idea. It seemed that it would work...and good find on the syringe plunger. If it's a tight fir, you could (if there were some allowance) maybe file the area where the seal sits to make it smaller; like a regular pump making the place where the seal touches should make it fit better (although, if it isn't extremely tight, then this shouldn't be a problem; making it smaller would just decrease it's sealing power)

Just a note on your pump size: changing from 15 to 22 mm changes 60 PSI from 16.2 pounds to 34.8; I'm assuming your okay with that though...

I would suggest getting some form of conical nozzle. It seems like you have a lot of power ready and waiting, it's just the nozzle isn't letting you use all of it. A conical nozzle should help quite a bit (doesn't it always?)

Looks like you're doing good; hopefully this turns out like a nice gun for you to use.

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Silence
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Re: "Requiem", my first homemade... made from Copper!

Post by Silence » Wed Jun 25, 2008 12:58 am

There's a lot of trial and error in pump-making, and I've never quite gotten it either. I've found the best method to be layers of duct tape around the rod and underneath the olive if the seal's too loose, or to cut a groove in the wood if the seal's too tight. Actually, if the seal is too tight, it may be easier to find a smaller olive (and you can make nearly any size piece stretch over the rod) and use tape from there.

And if you want, buy a length of PVC in the United States :p . I'm not sure whether the screw threads are compatible though.

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SSCBen
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Re: "Requiem", my first homemade... made from Copper!

Post by SSCBen » Wed Jun 25, 2008 2:57 am

devvo wrote:As I said I used a female threaded coupling at the end so I could change the nozzle, the plan was to experiment with various fittings and sizes finding what was the most effective bore, hovever as soon as I was finished I was quite happy with full bore 18mm, the problem of course you would have about 20 seconds of charge before it ran dry, we had 2 motorised test pumps that could fill and pressurise the system in 30 seconds but even then we where running out so fast we couldnt really have a war (then again at them pressures someone would probably of lost an eye!).

for the triggers we mostly used ball valves but one guy had a great one, he used a pressure blowoff valve, tightened the springs so it wouldnt blow at the high pressure he was using and had the blowoff lever where the trigger would naturaly be so he would just press the lever light and BANG.
I've experienced similar problems with my Supercannon II water gun. Once you start using large diameter nozzles you burn through water fast. 18 mm is pretty large (0.7 inches for those used to imperial/customary units), but likely not large enough to be the ideal diameter nozzle for pressures that high. In retrospect you'd be better off with larger diameter piping.

I didn't know anything about blowoff valves but Wikipedia seemed helpful. Interesting valve. That should open really fast at high pressure so it's easy to understand where the bang would be. Something simpler like ball valves would do the trick too but if you want instant feedback I guess this would be the way to go. :p
Aurum wrote:I know its been a while (over a week and a bit) but things are going so-so

The cork idea failed. it was ok, but... well trust me it didnt work. Next i tried super-gluing diphrapm seals onto a a wooden pole (after trimming the slightly. This was my best pump yet- fully water tight, up untill certain pressures when the pump could not long force the water BACK into the PC. the pressure int he PC was too great, and the water forced itself past the rubber seal in the pump.

At this point, ive now updated my pump shaft from 20cm of 15mm, to a (220% more volume) 30cm of 22mm. i tried with rubber seals again. No luck, i can only achive about 2/5 of full capacity (so about ~0.5L being compressed about ~0.3L)

---Not perfect, but at this point without a nozzle (firing from the 22mm piping nozzle) i can get the water to travel about 20 feet, in a large burst of water lasting less than 1 second
---But with the lucky nozzle i found (which is about 6mm) i can get te water to travel about 25-30 feet, in a jet lasting about 2 seconds. Both nozzles were tested at just above the horizontal (so 20-30* )

BTW
Im now using the pump from a feeding sringe (also agricultural, like the resevoir). slightly tight fit, but more water tight than the rubber diaphrapm seals.

I'll be testing tomorrow, but that will be it for 2 weeks. Im off to the USA state of Florida for a holiday. Woo! Sunshine!
The procedure I detailed in the APH guide should work fine. If you haven't tried that yet (I don't remember if you did) I'd suggest it.

While in the US buy some LRT... you'll appreciate it later until someone finds a good source of thick walled LRT in Europe. ;)

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cantab
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Re: "Requiem", my first homemade... made from Copper!

Post by cantab » Wed Jun 25, 2008 11:17 am

aEx155 wrote:A conical nozzle should help quite a bit (doesn't it always?)
With a caveat. The very last bit, before the water exits the gun, needs to be straight. (The ideal length of said 'last bit' probably depends on the nozzle size). Reducing conically from the barrel diameter to the nozzle diameter, rather than having a sudden step-down, is good, but having a nozzle that is internally conical right to the end is not good - the water then sprays outwards, as you might expect, since within a conical nozzle the water is traveling diagonally, so if it leaves the nozzle in that state, it will continue to travel diagonally.

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Drenchenator
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Re: "Requiem", my first homemade... made from Copper!

Post by Drenchenator » Wed Jun 25, 2008 1:06 pm

cantab's right, but many times this doesn't matter too much. The stream needs to be oriented back horizontally at the nozzle orifice, which a short length of straight pipe does well. But if the slope of the conic section is very low, it basically is going straight for our purposes. The straight length depends on how quickly the size drops in other words.
for the triggers we mostly used ball valves but one guy had a great one, he used a pressure blowoff valve, tightened the springs so it wouldnt blow at the high pressure he was using and had the blowoff lever where the trigger would naturaly be so he would just press the lever light and BANG.
Cool idea! With the pressures you're talking about, I'm sure it was a real bang when the valve opened. From what you said, it sounds like the valve opens easily, which might make it a good option for some people who dislike ball valves.
The Drenchenator, also known as Lt. Col. Drench.

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Silence
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Re: "Requiem", my first homemade... made from Copper!

Post by Silence » Wed Jun 25, 2008 3:55 pm

Blowoff valves remind me of the Navy's "pressure balanced fast opening firing valve". It's a really cool concept if you can make a (near-)perfect seal the whole way down the barrel. Admittedly, with fast opening times it's best for shorter barrels, though.
Drenchenator wrote:cantab's right, but many times this doesn't matter too much. The stream needs to be oriented back horizontally at the nozzle orifice, which a short length of straight pipe does well. But if the slope of the conic section is very low, it basically is going straight for our purposes. The straight length depends on how quickly the size drops in other words.
I'm not so sure about that - I think, for best results, there should be parallel walls at the end of every nozzle. Even a slight change in diameter spells trouble because the water that would have taken up that space has to go somewhere. In a gas nozzle it's not so important because the fluid can compress, but here you'd probably get some nasty eddies right at the aperture.
Last edited by SSCBen on Wed Jun 25, 2008 4:55 pm, edited 1 time in total.
Reason: Fixed broken quote tag

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cantab
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Re: "Requiem", my first homemade... made from Copper!

Post by cantab » Wed Jun 25, 2008 4:27 pm

As I said (in the topic in the mods forum), when I cut off the end of my WW Argon nozzle to widen it, I lost the end straight section, and the gun now sprays quite badly. Also I tried using a bic biro pen cap for a nozzle to my sprayer, with similar effects.

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