My Homemade (ideas, progress)

Build a homemade water gun or water balloon launcher and tell us about it.
totokan
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My Homemade (ideas, progress)

Post by totokan » Mon Jun 04, 2007 2:19 am

As with all other homemade things of mine, it's the T-Machine. I'm going to try and make a CPH. Opening a cylindrical version in the Lightning, I came up with a plan to make a PVC gun with 2L bottles as tanks, PVC cells for CP-like bladders, and I still need to come up with pump and valve designs. I'd make mock-ups, but I'm no good with art or blueprints. I'll have pics after I have parts.

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Silence
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Post by Silence » Mon Jun 04, 2007 4:28 am

Sounds good. Have you taken a look at the (relatively few) CPHs that have been documented? They should provide the general gist. :cool:

Just in case you weren't aware, latex rubber tubing (LRT) is most conveniently available from McMaster-Carr or from direct manufacturers online. McMaster-Carr ships from New Jersey, so it will probably take less than a day to get to you.

Use the largest and thickest tubing possible. The best combo is 1/2" ID, 7/8" OD tubing and 1" ID, 1.5" OD tubing. That provides 60 gauge PSI (PSI above one atmosphere, or 15), which is plenty for these purposes. You could use an even smaller size of tubing underneath for more pressure, but that would end up restricting flow, so performance wouldn't be too good.

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SSCBen
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Post by SSCBen » Mon Jun 04, 2007 12:17 pm

Welcome to Super Soaker Central totokan! SilentGuy has you covered on what it takes to make a CPS water gun. If you need any pictures of my CPH, I could provide a few that aren't online.

SilentGuy, I don't think you can add up the pressures quite like that. Certainly, more rubber does increase the total pressure, but not as you suggest due to the space inbetween each layered tube. Also, for most of the tubes (if you look at the listing), twice the thickness with the same ID does mean twice the pressure, but on some tubes you should notice a tapering off (such as the comparison between the largest 20 PSI tube and the largest 30 PSI tube). The pressure will be less than what is expected with straight addition. It is best to just make the chamber as thick as possible as take the pressure reading afterward. ;)

What we really need is a tubing manufacturer willing to make 1/2 to 3/4 inch thick tubes... that would be perfect!

totokan
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Post by totokan » Mon Jun 04, 2007 8:15 pm

So, I have searched for other people's CPH's so I can get an idea, but i can not seem to find anything, and the search feature does not aid me here.

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Scavenger
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Post by Scavenger » Mon Jun 04, 2007 9:15 pm

Well, there are Ben's different CPH guns, and then this
http://waterwarfare.com/forums/index.php?showtopic=308
and another on the old SoakerMedia forums, but DX updated the forums. There are probably a few more cylindrical ones, but I can't find them.

totokan
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Post by totokan » Tue Jun 05, 2007 12:10 am

I'm a bit unclear on the tubing, does it go in a main shaft between the tank and ball valve like on a water worm, or off to the side like a cps bladder?
EDIT: T-Machine Mark I will be a APH, pretty standard to start out. Mark II is what I'm trying to figure out here.
Last edited by totokan on Tue Jun 05, 2007 12:24 am, edited 1 time in total.

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SSCBen
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Post by SSCBen » Tue Jun 05, 2007 1:43 am

This should help a lot more than anything else posted: http://forums.sscentral.org/t3918/

This water gun has shot water over 60 feet back in 2004 when I first built it. I've been experimenting with it and tried a few less than successful things with it, so I'm trying to return it to how it looks in the thread I just linked to. Best water gun I've ever made. :)

totokan
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Post by totokan » Tue Jun 05, 2007 10:05 am

Sorry if I appear thick-headed, but the pressure chamber appears to be holding only a length of tubing, is this really all that you need for one?

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Silence
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Post by Silence » Tue Jun 05, 2007 1:15 pm

Yup. As you pump water, the tubing gets filled and expands - like one of those long, thin balloons. When you open the trigger valve, the rubber deflates and shoots out water. You'll want to use PVC or something sturdy to cover and protect the rubber.

If you didn't know, the rubber is what generates the constant pressure. :cool:

totokan
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Post by totokan » Sat Jun 09, 2007 1:07 pm

The local Home Depot didn't have all the pieces, so I had to go farther away to Lowes to get some. Now I have all the pieces for an APH, except I want a tank, so I also got some 2" ID SCH 40 PVC pipe. How exactly would I run that through the circuit?

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Silence
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Post by Silence » Sat Jun 09, 2007 3:44 pm

Just a note before you begin - you could use much larger tubing for the backpack. 3" or 4" would allow for more capacity, and especially if the large tubing comes as cellular core (and thus non-pressure-rated), the price will be somewhat low and so will the weight.

I presume you've gotten the hose barb on the APH so you can add a hose tube to the backpack. Get a reducing bushing like the 2"-to-3/4" one for the PCs - except that you want this one to go down to 1/2" with threads on the inside of the small socket. Then get a hose barb identical to what you got for the actual gun and screw that into the reducing bushing.

Remember, there's tons of flexibility here, and no "correct" method of accomplishing things. So feel free to do anything that gets the job done. Ie, specific instructions aren't really necessary if you know in advance what you're trying to build. :cool:

Good luck! Sounds like the project is moving along nicely. :)

totokan
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Post by totokan » Sat Jun 09, 2007 4:32 pm

thanks. After looking through my parts, I found out my 1/2" tee and one of my 2" x 3/4" reducers have a threaded side. Any way to work around this?

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DX
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Post by DX » Sat Jun 09, 2007 4:44 pm

You'd have to buy a corresponding threaded part. Let's say that the reducing bushing has threads on the 3/4" end - you'd have to buy a 3/4" male adaptor, which screws in, then connect the other end to the rest of the gun with a segment of 3/4" pipe. If this will be under pressure, then you also want to wrap teflon sealant tape on the threads.

If it is too much of a hassle, you might as well return the threaded fittings and buy the same ones without threads, if available.
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totokan
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Post by totokan » Tue Jun 12, 2007 10:44 pm

Soon enough, I'm going to the Home Depot to replace the parts that don't work and get some I'm missing. Hopefully, after this trip, I'll be ready for gluing. All of my PVC is cut and sanded, except 1/2" because i still need some parts there. So, I'll post pics when it's all ready. Quick question: when cutting the pipe, is it better to have shorter lengths? I have the pvc as short as I can make it (1 1/2" long) that still connects the Tee to the ball valve, but I'm wondering if a longer segment of pipe is worth it.

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DX
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Post by DX » Tue Jun 12, 2007 11:06 pm

There are two schools of thought on the matter. The first is for long segments. By using long segments, repair is very easy if you screw up somewhere, or if you drop the gun and somethiing snaps off. When using short segments, you don't plan on screwing up in the first place. The short segments keep the gun as compact as possible. Either way works just fine, provided that you prime and glue correctly.
Mess With the Best, Get Soaked Like the Rest!

2004 Red Sox - World Series Champions
2007 Red Sox - World Series Champions!

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