Air Pressure 2,5 litre firing chamber

Build a homemade water gun or water balloon launcher and tell us about it.
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-G-JiV-
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Air Pressure 2,5 litre firing chamber

Post by -G-JiV- » Sun Oct 10, 2010 9:10 pm

I am modifying Soakers since a long time...
First I have just changed nozzle sizes...later upgrading backpacks...then upgrading size of reservoir and pressur-chamber and I even built up a whole CPS...

I am now constructing an Air Pressure-Water gun. As firing chambers I will use 5 x 0,5 litre PET bottles.
Here is my first question: People tested these bottles, they can hold 20 bar pressure till they explode, can I thrust this ? I do not want my pressure chambers explode, because I do not install a valve...
I think 5 x 0,5 litre bottles are better than one big bottle with 2,5 litre, what do you think ?

I also have a question related to glue: I need a strong, pressure safe glue. What do you recommend ? PVC glue? Seconds glue with Cyanin-Spray ?

Any advices or thing I would have to notice, please tell me, I will let my imagination and creativity its way...Let's see what comes out in the end :D

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C-A_99
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Re: Air Pressure 2,5 litre firing chamber

Post by C-A_99 » Sun Oct 10, 2010 10:43 pm

If the bottles are designed for soda, then they should be able to hold pressure fairly well. There is much dispute about them from other places I've read, mainly because the bottles are designed to store water under pressure instead of air. On the other hand, Waterwolf (now inactive) did some stress tests on soda bottles. They were powered up to 140PSI and took some stonings before they bursted.

In the end, I would still avoid using them unless you need a light and quick solution. I don't know how well they hold up over time. For PVC homemades (APH's) you may want to use PVC air presure chambers.

As for glue, most of us here prefer epoxy and epoxy putty. Epoxy is used to seal those small cracks, where the properties of the highly viscous liquid will fill in those tracks. Epoxy putty is used for larger areas and more heavy duty work, but can often also be used if you're simply too lazy to use epoxy. I know I've done that a lot. PVC primer and cement are exclusively used for putting PVC fittings together, they are not useful for anything else. (The primer is also required to ensure durability.) When properly welded, the connection of primer and cement is usually stronger than the PVC itself. (Someone correct me if that's not true.)

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-G-JiV-
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Re: Air Pressure 2,5 litre firing chamber

Post by -G-JiV- » Mon Oct 11, 2010 7:12 am

Thanks, I will remember this :) But due to the fact that the gun is a prototype, I will try the PET-bottles first. If the gun works properly I will see, if I replace the bottles with something else.
Do you know Caynin-acrylate-glue which can be used with an activate-Spray and then immediately it is fixed and hard ? May I used this mixed with sealing-gel ? My experiences showed that this seals and fixes everything quite good and in some seconds it is done.
By the way, I do not only use PVC---but a mixture of things I have at home. Let's see what comes out in the end :)

Image

That is the firing chamber-area. I need anything I could fix the bottle's cap on the pipe, have to be seal and really strong, because I will reach 4-6 bar pressure(60-90 PSI)
I have tried a special glue now, let's see whether this is strong enough...Need a glue that connects cupper and PET very well...this is difficult to find^^
Last edited by -G-JiV- on Mon Oct 11, 2010 7:33 am, edited 1 time in total.

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Killi101
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Re: Air Pressure 2,5 litre firing chamber

Post by Killi101 » Mon Oct 11, 2010 3:44 pm

looks nice, but why do you need the hose clamps? secondly, i dont think the glue will hold, it may but i wouldt reccomend it, it may fly off after a few tries. the good part is the caps can be used with any new bottles if they need to be replaced. when this is done it will be a beast!! :)
Water:
dont like drinking much
like to throw it at people

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-G-JiV-
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Re: Air Pressure 2,5 litre firing chamber

Post by -G-JiV- » Mon Oct 11, 2010 5:32 pm

Killi101 wrote:looks nice, but why do you need the hose clamps?
These clamps fixes the PVC-tube, which connects the T-element, so they are verrryyyyyyyy important^^ They will have to keep things together when 70 or more PSI are inside the firing area... :)
Killi101 wrote: secondly, i dont think the glue will hold, it may but i wouldt reccomend it, it may fly off after a few tries.
I have used two types of glue, mixed toegther. one is for sealing, the other is a special superglue...I will think about another safety-fix for this, but at the moment I do not know what to sue :D
Killi101 wrote:the good part is the caps can be used with any new bottles if they need to be replaced. when this is done it will be a beast!! :)
Haha, lets see, whether it is a beast !!! or just a small monster or at least a failed idea... :rolleyes:

Further progress is made, promised, and also documented here.

Pump was installed today, trigger is ready and installed and also the backpack is ready. What I have to do now is looking for a backpack to put in the the waterbackpack(because it is more comfortable :rolleyes: ) and 5 x o,5 litre Coca Cola bottles...And I have to make carring the gun more easily, parts are not fixed together at the moment.

IF all this is done, gun is ready for action :)

By the way, it has got a 7 X:: nozzle...

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cantab
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Re: Air Pressure 2,5 litre firing chamber

Post by cantab » Mon Oct 11, 2010 8:07 pm

-G-JiV- wrote:I have used two types of glue, mixed toegther. one is for sealing, the other is a special superglue
This may be a bad idea. Glues have specific chemistries to make them work. By mixing two they could each "interfere" with the other.
I work on Windows. My toolbox is Linux.
Arsenal:
Super Soaker: XP215, 2xXP220, Liquidator, Aquashock Secret Strike M(odded), Arctic Blast M, CPS1200, CPS2100, SC Power Pak, 3l aquapack, 1.5l aquapack
Water Warriors: Jet, Sting Ray M, Shark, Argon M, Tiger Shark, PulseMaster
Others: Waterbolt, The Blaster, Storm 500, Shield Blaster 2000, generic PR gun, generic backpack piston pumper (broken), 3l garden sprayer M, 10l water carrier:

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-G-JiV-
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Re: Air Pressure 2,5 litre firing chamber

Post by -G-JiV- » Mon Oct 11, 2010 9:39 pm

That is right, but if you use the correct ones and mix them together, you may even get a better result as if each glue is used seperately. Generaly speaking, you are right, chemistry can interfere with each others and we just do not know what happens then.
This is why I have tested them together lots of times and they work well together :) .
But I am sure it is not enough to "just glue the cap and the cupper pipes together"...Therefore I am looking for a mechanical fixment, hm...This have to be solved, any advices ? :D

I will test the gun as soon as I have the missed equipment, tomorow I may finish and test it out, hehe^^
Pictures will follow, either it exploded or it just worked fine ;)

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cantab
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Re: Air Pressure 2,5 litre firing chamber

Post by cantab » Mon Oct 11, 2010 11:51 pm

A couple of ideas:

Firstly, take a 15 mm compression fitting, and drill a hole in the cap so it can be slipped like a washer before you screw the nut on. You could use a straight connection, or possibly a drilled stop end. I'm not sure if the dimensions will work out though.

Secondly, drill a 15 mm hole through the cap, then slot in a 15-22mm adapter, with the 22 mm to be on the inside of the bottle. Fasten the 15mm end to the blaster, physically blocking the cap from leaving. Again, I'm not sure on dimensions; a 22mm pipe might not give space to screw the bottle onto the cap. You could use a smaller reducer but then you cut the blaster's power, although if you have multiple pressure chambers it may not matter.

I'd suggest checking everything fits before soldering or tightening nuts.
I work on Windows. My toolbox is Linux.
Arsenal:
Super Soaker: XP215, 2xXP220, Liquidator, Aquashock Secret Strike M(odded), Arctic Blast M, CPS1200, CPS2100, SC Power Pak, 3l aquapack, 1.5l aquapack
Water Warriors: Jet, Sting Ray M, Shark, Argon M, Tiger Shark, PulseMaster
Others: Waterbolt, The Blaster, Storm 500, Shield Blaster 2000, generic PR gun, generic backpack piston pumper (broken), 3l garden sprayer M, 10l water carrier:

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-G-JiV-
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Re: Air Pressure 2,5 litre firing chamber

Post by -G-JiV- » Mon Oct 11, 2010 11:56 pm

Good idea^^ I will try my contruction first, as it is now, if it break, I will try this :) .

cantab wrote:I'd suggest checking everything fits before soldering or tightening nuts.
I am sorry, but I cannot translate this, so I understand, can say in other words ? :D

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cantab
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Re: Air Pressure 2,5 litre firing chamber

Post by cantab » Tue Oct 12, 2010 12:47 am

Make sure all the parts will fit together before you build it.
I work on Windows. My toolbox is Linux.
Arsenal:
Super Soaker: XP215, 2xXP220, Liquidator, Aquashock Secret Strike M(odded), Arctic Blast M, CPS1200, CPS2100, SC Power Pak, 3l aquapack, 1.5l aquapack
Water Warriors: Jet, Sting Ray M, Shark, Argon M, Tiger Shark, PulseMaster
Others: Waterbolt, The Blaster, Storm 500, Shield Blaster 2000, generic PR gun, generic backpack piston pumper (broken), 3l garden sprayer M, 10l water carrier:

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-G-JiV-
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Re: Air Pressure 2,5 litre firing chamber

Post by -G-JiV- » Tue Oct 12, 2010 7:58 am

Haha, ok, that was what you wanted to say. Yea, I will do this, gun is nearly finished :) . Thanks, It is exciting building such a gun, because you do not know what comes out in the end and whether you made everything right :) .

Ok, enough written, I will now go and finish my work ;)

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-G-JiV-
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Re: Air Pressure 2,5 litre firing chamber

Post by -G-JiV- » Wed Oct 13, 2010 9:34 am

Ok, gun is finished, looks nice and I think it will not crack easily...It weighs less than a CPS 2000. Reservoir is a backpack, holds 4,5 litre of water(will make this another time and double reservoir volume :) .
Pump is great, , is not tracked but it is strong built(strenghten with a metal core), so you really cannot break it by pumping, may you drive over with a car, ok than it will probably brake :D . Pump volume is amazing, roughly 170 ml each pump, and it also works smooth and pumping is easy till the pressure gets high^^
Firing chambers can be changed easily, it now has 2 litre volume, really nice. You only need about 10-12 pumps(depend how much you move the gun each pump)to get full pressure. Nozzle is rated at more than 20 X::, output is a bit under 2 seconds, so about 1000 ml output /s. Range is more than CPS 2000(it would says hmm about 60 feets) but the Powerrating :D is incredible...I will have to use it carefully in a water battle, i do not want to hurt anybody...haha
Nozzle can be changed into 5 X::, 1X:: and no nozzle(firing time less then 1 seconds, thus incredible power and output, range about 45 feets)

Firing pictures will follow, it is rather cold out here in Austria today...

Thanks for advices, the gun is more or less finished and works really fine^^

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Killi101
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Re: Air Pressure 2,5 litre firing chamber

Post by Killi101 » Wed Oct 13, 2010 5:50 pm

wow, it is a beast, but it would be adviseable for all the bottles to be the same that way you can ensure the bottles are safe, it seems to work well for you, but for the future...
Water:
dont like drinking much
like to throw it at people

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-G-JiV-
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Re: Air Pressure 2,5 litre firing chamber

Post by -G-JiV- » Wed Oct 13, 2010 6:03 pm

Haha, yes you are right. it is just that I found a better way to fix the bottles, but as long as the superglue can fix the bottles I will not change them, day will come when it breaks down, then the bottles are replaced by similars, so I use only bottles of one type :) .

The bigger backpack(9 litres) is needed...2,5 times filling the firing chamber and the whole water is used...its a beast :D

tomorow I will make firing pictures

Fredcompany
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Re: Air Pressure 2,5 litre firing chamber

Post by Fredcompany » Thu Oct 14, 2010 5:10 pm

That looks scary...
Nice job!
I'm a dude

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