I want to build an APH...

Build a homemade water gun or water balloon launcher and tell us about it.
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mackiwi
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Joined: Wed Nov 17, 2004 4:05 am

Post by mackiwi » Tue May 31, 2005 6:35 am

Hi everybody, I am wanting to build an APH pretty much identical to the one in Doom's article. A couple of things I wanted to clear up first...seeing as it's air pressure, is stream dropoff a big problem in this design? Also, if I make the PC's the same size as the original design how many pumps is recommended to stay safe (I.e before I damage the gun or something like that). And finally, as water is coming in from the backpack, is there any pump lag as water is sucked in all the way from the backpack to the PC? I'm really looking forward to giving this a shot as I've had no previous experience with PVC piping and I thought it would be a good place to start. Hopefully I can find all the parts I need!
Thanks in advance for any advice.

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SSCBen
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Post by SSCBen » Tue May 31, 2005 10:16 am

Stream drop-off exists, of course.

You'll know when you've pumped this water gun enough. The PVC can take far more pressure than your average Super Soaker water gun. The pump will get considerable harder to pump, and that is where you should stop to prevent dangerous pressures.

As for "pump lag", I suppose that exists to a certain extent. You have to make sure the backpack and water gun are correctly siphoning and everything is sealed for it to work best.

mackiwi
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Joined: Wed Nov 17, 2004 4:05 am

Post by mackiwi » Wed Jun 01, 2005 8:31 am

Thanks, doom...I was thinking though, I have an old now-broken CPS 2700 which I could salvage the PC from, do you think if I made the ID 1/2" I would be able to use the 2700's PC in the APH (or CPH, in this case) and do a heavy K-mod to it? I'd really like to have a constant pressure gun but don't think I am experienced enough to begin playing around with latex rubber tubing yet.

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Spinner
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Post by Spinner » Wed Jun 01, 2005 9:37 am

What makes you think that using latex rubber tubing is hard? I'd have thought it would be simple enough.
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SSCBen
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Post by SSCBen » Wed Jun 01, 2005 10:11 am

Whoever is getting the thought that homemades are hard to make in your head is wrong. The only people who say that haven't made one. If homemades were hard to make, I wouldn't make them.

I would say that it most definitely would be easier to use Latex rubber tubing as opposed to figuring out a way to attach a CPS 2700s PC. Latex rubber tubing is extremely easy to use, you know. All you need for a basic CPS gun is some barbed fittings, tubing clamps, and a length of latex rubber tubing. Assembly is self-explanatory for the most part: just attach everything together securely and make sure one end of the tube is blocked off.

I made this constant pressure homemade with leftover parts. Hopefully that image should get your started. ;)

mackiwi
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Joined: Wed Nov 17, 2004 4:05 am

Post by mackiwi » Wed Jun 01, 2005 8:48 pm

Thanks again doom. I think my main problem is going to be finding LRT over here in New Zealand, it isn't quite so easy to find it seems. So do I just attach the barbs and tubing clamps to opposite ends of the tubing or have I got a completely wrong idea here? These probably sound like obvious questions, but I am new to all of this so bear with me here!

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SSCBen
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Post by SSCBen » Wed Jun 01, 2005 11:43 pm

Just keep reporting back to us to make sure you're doing everything correctly if you are unsure.

All you really need to do to make the CPS chamber is securely attached to barbs. One barb will have the end sealed off with a threaded endcap.

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BlueMage
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Post by BlueMage » Wed Jun 08, 2005 10:36 pm

doom is right. they are actually pretty easy. the hardest part is finding the weird PVC bits like adapters and check valves. the rest is just cutting, gluing and making sure it doesn't leak.
Image

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