PVC/Copper Hybrid SCH

Build a homemade water gun or water balloon launcher and tell us about it.
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SEAL
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PVC/Copper Hybrid SCH

Post by SEAL » Sun Aug 15, 2010 4:26 pm

First of all, the title is not a typo. This is not my CPH. I'm not building that until this winter. This is just something I decided to make in between so I wouldn't get bored. It's not a very serious project.

Here is a drawing. For some reason I couldn't upload my saved PVC designer picture on my photobucket account, so I had to use paint. But don't worry, I learned a few tricks, so the picture is a lot better then my APH picture.
Here you go.
Image
Note: The goldish parts are copper, and the white parts are PVC. It's not to scale.

SCH stands for Super Charger Homemade. It's basically a homemade that has to be charged by the hose. A 2L would fall under this category. (The kind that I made anyway.) If nobody has used this term before, or if there isn't a different term for this kind of blaster, then I'd like to coin this term.

Originally, I wanted to make the whole thing out of copper, 'cause I had some copper pipes laying around, and I could use a copper ball valve without buying converters. But I wanted to use 3" pipe for the reservoir, so I looked in Lowes, but the biggest I found was 2" which was insanely expensive at $130.00 or something like that. So I figured if they did make 3", it would be even more costly. So I decided to make the reservoir out of PVC, and the valve and front of the gun out of copper. The front will be 3/4 inch, and the reservoir will be 3".

I have 3/4" copper and PVC, and 3" PVC. The only things I need are the bushings, a 3" endcap, and a copper 3/4" ball valve and male adapter. (For the hose.) I plan on using the same refilling hose as my 2L.

Now the big question I want to ask you, is will it work? I know you need to have an air pocket in the reservoir. Will this shape work? If not, I have a backup plan. It should work though, the CPS Splashzooka has the same shape.
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cantab
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Re: PVC/Copper Hybrid SCH

Post by cantab » Sun Aug 15, 2010 6:22 pm

If that is an empty chamber, it won't work very well. Air rises, so if you aim upwards - which you want to do - it would just vent all its air and lose pressure. It would shoot if you aim downwards, but that's not too helpful.

You have a few possible solutions

1) Put an elbow in and hold the PC upright with the nozzle at the bottom. This is the simplest way, but may reduce performance.
1a) Related - put a dip tube down inside the PC, this lets you have the elbow and valve at the TOP which gives better ergonomics, but you'll never be able to fully empty the PC.
2) Put a piston in, like in SCII and the LPD (limited pressure drop) blaster.
3) Use a CPS chamber
4) Inflate a balloon and place it inside the chamber. Weight it or glue it to the back end. This is an untested idea but might work. It functions in the same way as the piston - you pump water in and the air inside the balloon is compressed, creating pressure, while the rubber skin prevents the air going to the top.
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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SEAL
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Re: PVC/Copper Hybrid SCH

Post by SEAL » Sun Aug 15, 2010 7:04 pm

This was meant to be a last-resort type blaster. The kind of gun you'd pull out when all your other blasters are empty. So I want it to be compact.

I'll review the solutions.
1) This was my original back-up plan. I was planning on using a 45 degree elbow. That would give it better performance then a regular 90 degree elbow.
1a) That would be pretty difficult to affix. I'd rather not do that.
2) I don't know how SCII works, but if I did put a piston in it would probably cost a lot. I may make a SCII gun in the future. I've never heard of LPD. Is it a homemade blaster?
3) Yeah I could give it CPS. (Then it would be a CPSCH?) I'd have to read up on CPH tech though.
4) I don't know about this. I'd rather do solutions 1 or 3.

I'll have to think it over. By the way, what do you mean by "If that's an empty chamber"? Do you mean empty by not having an intake tube, balloons or LRT? Because I wasn't originally planning on putting any of that in there.
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Fredcompany
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Re: PVC/Copper Hybrid SCH

Post by Fredcompany » Sun Aug 15, 2010 7:29 pm

If you don't put any of that in, it'll have the problems Cantab described.
The Splashzooka is (I think) CPS.
The simplest solution is probably the elbow, or if you can find one, the piston.
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SEAL
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Re: PVC/Copper Hybrid SCH

Post by SEAL » Sun Aug 15, 2010 8:37 pm

I think I'll use the elbow. It's probably the simplest and cheapest alternative to the current design.

Yes the Splashzooka is CPS. (That's why it has CPS at the front of it's name.) I think it works like my design except the water fills up in a rubber bladder instead of the reservoir. I thought that rubber bladders needed air pockets too, but now I'm not so sure.
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Silence
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Re: PVC/Copper Hybrid SCH

Post by Silence » Sun Aug 15, 2010 8:50 pm

Rubber bladders don't need air pockets, in fact the case for the bladder usually has a hole to let air in and out and keep the air pressure constant.

Someone once suggested using a bag to separate the air and water, which is similar to cantab's last suggestion. I don't think it's been done, however, it would probably work if you used Teflon tape both inside and outside the bag to stop the threads from cutting it.

LPD stands for Limited Pressure Drop. But a piston/bag inside a standard air pressure chamber (like in Supercannon II and in the 2 liter homemade) is fine since it doesn't sound like you're going to store much water. If you were shooting a Splashzooka quantity of water, then you'd start to notice the pressure/speed/range dropoff at the end of the shot.

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SEAL
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Re: PVC/Copper Hybrid SCH

Post by SEAL » Sun Aug 15, 2010 11:31 pm

Okay, cool. Thanks for clearing those things up!

Now, I wonder if I can go to Lowes tomorrow...
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mysterio
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Re: PVC/Copper Hybrid SCH

Post by mysterio » Mon Aug 16, 2010 12:07 am

Just wondering, are you going to use a pair of pistons? if so, youll need a air release at the end.

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SEAL
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Re: PVC/Copper Hybrid SCH

Post by SEAL » Mon Aug 16, 2010 1:20 pm

No I'm not going to use pistons. I'd rather go for the cheapest & simplest way possible.

And I don't think I can go to Lowes today...
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SEAL
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Re: PVC/Copper Hybrid SCH

Post by SEAL » Tue Aug 17, 2010 1:59 pm

Hey, just wondering, doesn't the SC 400 work the same way as my original design? I mean, it is air pressure, and the reservoir is tilted sideways. Unless it uses an intake tube, but then how would you fill it up with the QFD? I always thought you couldn't quick-fill something with an intake tube, but I may be wrong.

Here is a link to the iSoaker review page.
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cantab
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Re: PVC/Copper Hybrid SCH

Post by cantab » Tue Aug 17, 2010 5:13 pm

I know no reason why you couldn't quick-fill a blaster with an intake tube.
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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SEAL
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Re: PVC/Copper Hybrid SCH

Post by SEAL » Tue Aug 17, 2010 6:43 pm

So the water would enter the tank through the intake tube? I thought... Oh never mind.

But why would an intake tube make it so you wouldn't need an air pocket? If I were to add an intake tube, then when I fill it up by the hose, water would enter through the tube, and fill the reservoir. But wouldn't you still need an air pocket? I mean, how else would the water have enough pressure to shoot?

Forgive me for all these questions. I hate being a newbie...
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Re: PVC/Copper Hybrid SCH

Post by cantab » Tue Aug 17, 2010 7:01 pm

When the chamber is empty of water, it's full of air. When water is then forced in under pressure, that air must be compressed. And that's where your pressure comes from.
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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SEAL
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Re: PVC/Copper Hybrid SCH

Post by SEAL » Tue Aug 17, 2010 9:53 pm

I knew that, but the reservoir has to be tilted a certain way in order to trap the compressed air right? So if I were to go with my current design, when I'd shoot it, of course I would point it up at say, 45 degrees, which would move the air pocket up to the top of the tank, so when I'd go to shoot it, all the air would escape out the nozzle, and the water would be left in the reservoir without any force behind it to shoot. Am I right? If I am, then how does the SC 400 shoot without losing all it's air? Or do you have to quick-fill it and then pump it? I've never owned an SC 400.
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Re: PVC/Copper Hybrid SCH

Post by cantab » Wed Aug 18, 2010 5:36 pm

It has an intake tube that extends to near the back of the reservoir and is weighted so it sinks.
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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