APH or CPH?

[Goldfish4209]

I am building an APH, and I was just wondering which is better: An APH or a CPH? I know the APH is more powerful but takes more pumps to pressurize. What I was wondering is, in the SuperCPS guide, Ben said it was possible to pop the LRT when pumping too much. That's what kinda stopped me from liking CPHs a lot. My question(s): how easy is it to damage a CPH by over-pumping, and if you take into account that risk, is the APH or CPH better?

[Ben]

A CPH is much more useful than an APH in my mind. The only advantages to the APH is that no parts must be ordered and you have the potential for higher flow riot blasts. But, a CPH can easily be the APH in range and often does. Range is the primary measurement of power in my mind so a CPH is more powerful.

A CPH has constant range and water output which alone is one reason to use the design. The drop off in the APH can be very annoying, but not compromising as long as you use burst shots and continually pump it back to top pressure.

You can avoid the popping problem by making the pressure chamber much larger than what you need. I've only ever had the pressure chamber of a CPS water gun pop once unintentionally and it happened while someone who didn't realize how the water gun worked was using it (he was used to air pressure and was waiting for the pump to get hard). Usually the tear is small and isolated to a few inches of the chamber. You can cut it off and continue to use the remainder of the chamber.

Another option is a pressure relief valve like in normal water guns but you'll need to restrict the expansion of the chamber for this to work.

Popping isn't much of a problem in my opinion. It's really easily avoided and I think it's much better than its air pressure counterpart, bursting pipes.

[Goldfish4209]

OK, thanks. That changes my view on CPHs a little.

I'm still going to build an APH first though, to get some experience.

[C-A_99]

They're just about the same difficulty to build, at least from my experience. Personally, I didn't do so well in my CPH and made some stupid decisions, such as using 3/4 piping for the PC area instead of 1/2", meaning I have no chance at all to make a trigger for it now. I also didn't use good barb sizes nor good LRT sizes for layering. (basically, I was working with it in a time of outdated concepts) Now, with modern techniques for layering LRT, you shouldn't have much trouble achieving good power levels.

If, for whatever reason, you still want to build the CPH, I would avoid making the pressure chambers too large to ease pumping, but having never built the APH, I'm probably not one to make suggestions about it.

[Ben]

Both designs are worth building so I don't think you'll regret building an APH first. An APH is more straightforward in my opinion mainly because you can buy all the parts in one trip.

Since this is your first time, if you're ever confused about anything or have any questions or suggestions for the guide, let us know here. I'm trying hard to make my APH guide as good an introduction to building water guns as possible.

[Commander Soakage]

I just finished my first homemade. it is a cph and it really was not hard to build at all.

[Silence]

Sound neat. Do you have any pictures? What ranges are you getting, and with what nozzles?

[Drenchenator]

I second a request for pictures and stats. Congrats on finishing one!

[aEx155]

I'll third the request...hopefully this one encourages me enough to build one myself. I've been thinking about it for a while...