simple homemade cps gun help

[Commander Soakage]

for anyone who wants to know where to get LRT, you can get it at a medical supplies store. I found a store in albuquerque (my home town) that sells it by the foot with various thicknesses and diameters for great prices (approximately $1.75~$2.98 a foot)

[Ben]

Make sure it's the right stuff. Most of the stuff they sell is too thin and has too small a diameter. If you did find a good local place, that's great. I know that some people call LRT "surgical tubing" because of its use in medicine, but I didn't think to look there.

[Commander Soakage]

the diameter is 1/2 inch and the thickness is 1/8 inch tell me if I got the right stuff or not

[Ben]

1/8 inch may or may not be too thin for your tastes. McMaster-Carr rates the same tube's maximum pressure at 25 PSI, which should be adequate, but not great. The CPS 1000 operates at 23 PSI for comparison. I'd layer on some more tubing or bike tubes or see if they have a thicker tube available.

[Commander Soakage]

bike inner-tubes, balloons, I would REALLY like a good long list of everything that can be used for cps blasters. Maybe I'll start a thread.

[Ben]

It comes down to gas pressure regulators, balloons, rubber tubing, and bike tubes really.

There also are other CPS type systems no one has made. Be creative. I know for a fact that there are designs out there that no one (well, other than me) have thought of because I've thought of them and haven't told too many people.

[Commander Soakage]

ben, it's time to release you CPS secrets. if you know about a material that no-one else has considered you should tell us.

[Ben]

No, it's not time. I want to get a patent and releasing it to the public before filing is a good reason to deny a parent.

Once I get pending status (or whenever is safe) I will post about my new design. It is significantly different than anything else and should at the very least offer a new option in homemade water guns.

Please don't discuss this further.

[Commander Soakage]

I think I know what i'm going to do. ben, I took a look at your APH and an idea spawned.
aphparts.gif

the long, black thing is rubber tubing and the it is attached by an elbow


P.S. i apologize to ben for modding his image

Originally Posted by Ben

1/8 inch may or may not be too thin for your tastes. McMaster-Carr rates the same tube's maximum pressure at 25 PSI, which should be adequate, but not great. The CPS 1000 operates at 23 PSI for comparison. I'd layer on some more tubing or bike tubes or see if they have a thicker tube available.

correction, ben. they say that a 1/8 inch thickness can hold 48 psi.

[Ben]

As I said in your other thread, there's no reason to change the APH layout to work with LRT. Use a design made to work with LRT like SuperCPS: http://www.sscentral.org/homemade/supercps.html

This will cost less and perform slightly better than using the APH layout. The APH layout is designed for air pressure and thus the chambers must be fed from the bottom so the air can float on top. With LRT you do not have that limitation, so you should make the water flow straight to the nozzle.

Don't worry about modifying my images. It's not illegal and I don't even care. I put them online so you could look at them, modify them, and ask questions about them.

correction, ben. they say that a 1/8 inch thickness can hold 48 psi.

I don't know what tube you're looking at, but the one I'm looking at on McMaster-Carr says 25 PSI. See the attachment. Is that information coming from your supplier? If so then I think it's inaccurate unless they have a stronger latex, which is unlikely from what I've seen. The people who make this stuff have one method and they won't change it unless you'll pay them a lot of money.

[Commander Soakage]

the major reason I want to use your aph design to make a cph is because your aph design is more simple and alot cheaper.

[Ben]

I don't know how the APH design is simpler or cheaper. It uses larger 3/4 inch pieces that cost more, so it definitely is not cheaper. It is no simpler than the SuperCPS design as far as I can tell. The only differences are the position and orientation of a tee and the size of the pieces. Is there anything you're confused about?

The APH design again would perform worse because it has a turn in the water flow, introducing some turbulence and reducing the flow. The SuperCPS design on the other hand has no turns, improving performance.

[Commander Soakage]

you have a point about the curves ben, and the price may be about the same, but what if I put the pressurized chamber in the back instead of on top or put a check valve right here
aphparts.gif
and used 1/2 inch pipes instead of 3/4 inch pipes.

the aph is also smaller.

[Ben]

I don't know what you mean about putting the PC in the back or on top. It's already on top isn't it? I'm confused. Could you explain?

Putting an extra check valve there would just waste money. Moving one of the check valves there wouldn't change the design. I'm confused as to why you're suggesting that. Is there any advantage to that location?

The APH is not smaller. They're similar in length, but you can make the CPS one much shorter if you shorten the chamber. The CPS one is also less tall.

Regardless, if you use 1/2 inch pipe but don't put the nozzle inline with the PC, the only difference between the SuperCPS design and what you've made is that the nozzle isn't inline with the PC. There's no disadvantage to putting the nozzle inline with the PC, only an advantage in performance.

[Drenchenator]

the aph is also smaller.

Dead wrong. A CPH as built in Ben's guide is smaller and probably lighter too. The APH's chambers just make it that much taller. I can attest to this because I've used both Ben's CPH and one of his APH's.

I suggest that you read this article; you seem a bit confused about the purpose of the check valves. You can't just arbitrarily introduce one--it could seriously mess up the gun. The two check valve system is the simplest way this can be done.

And I'm sorry; I'm gonna ask it--what's wrong with the standard CPH design? It's the best possible design for this kind of a gun. The flow's completely uninterrupted from the chamber through the valve and out the nozzle.