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Replacing a spherical pressure chamber

Posted: Sun Aug 17, 2008 5:02 pm
by 11ilee
Is there any possible way to replace the spherical pressure chamber in the CPS 1500 with a cylindrical one?

Re: Replacing a spherical pressure chamber

Posted: Sun Aug 17, 2008 5:09 pm
by aEx155
11ilee wrote:Is there any possible way to replace the spherical pressure chamber in the CPS 1500 with a cylindrical one?
Not without some modification.

You would need to replace the spherical PC housing with a cylindrical one to account for the different expansion; then you would need to mount it. You would also need to find a way to connect the new LRT to the old connection, since (I think) it's different.

It might be difficult considering the size and shape of the 1500; there's not much length (which is what you need) to work with. You might be able to extend it into the reservoir and add a backpack or other on-board reservoir, but I'm not sure how that would affect balance, aesthetics, etc. ...

Re: Replacing a spherical pressure chamber

Posted: Sun Aug 17, 2008 5:19 pm
by 11ilee
So it would be too difficult to be practical?

Re: Replacing a spherical pressure chamber

Posted: Sun Aug 17, 2008 5:21 pm
by Silence
Yep. You'd need to fit a new one and it probably wouldn't look too good in the end.

Plus, the CPS 1500 already has a decent pressure chamber, in my opinion.

Re: Replacing a spherical pressure chamber

Posted: Sun Aug 17, 2008 5:23 pm
by Specter
another option could be to K-mod it with a few balloons.

Re: Replacing a spherical pressure chamber

Posted: Sun Aug 17, 2008 5:26 pm
by 11ilee
But what if the pressure chamber bursts, then how can I fix it? (If replacing the pressure chamber is too difficult.)

Thanks.

Re: Replacing a spherical pressure chamber

Posted: Sun Aug 17, 2008 5:27 pm
by Specter
I think i heard before that someone made a new PC out of a bunch of balloons.

Re: Replacing a spherical pressure chamber

Posted: Sun Aug 17, 2008 5:38 pm
by SSCBen
People have replaced spherical pressure chambers with cylindrical ones before. A guy named AquaTech did it back in 2001 or 2002, way before anyone else.

I don't imagine it would be too difficult. With a hacksaw, some epoxy putty, sandpaper, a barbed fitting, some tubing clamps, and the right coupler I could have a new pressure chamber attached in minutes. It would be a permanent modification obviously, but it'd be rather simple.

If the pressure chamber isn't popped then I wouldn't suggest replacing it. If it is popped, you have nothing to lose by replacing it. The main problem is that a sphere and cylinder are very different shapes and the layout of the water gun isn't the best for a cylindrical chamber, but with a small one it'd work fine.

Balloons are an option too as Specter said. I think you can take the rubber part of the PC off the plastic part and attach them there. I've never tried though. I think DX has. PM him if he doesn't post here.

Re: Replacing a spherical pressure chamber

Posted: Sun Aug 17, 2008 5:58 pm
by 11ilee
So, I've got two questions,

How many balloons should I put to get maximum shot time, power, and range?

Also, If I replace the chamber with a short tube with psi 100, could the power of the gun be drastically raised?

Thanks.

Re: Replacing a spherical pressure chamber

Posted: Sun Aug 17, 2008 7:19 pm
by cantab
What exactly do you mean by "a short tube with psi 100"?

Re: Replacing a spherical pressure chamber

Posted: Sun Aug 17, 2008 7:24 pm
by 11ilee
Well, I read in the SuperCPS article that a CPS 2000 uses a pressure chamber with 45 psi, and that increased psi meant increased performance, (I may be wrong, I'm no expert on waterguns.)

Re: Replacing a spherical pressure chamber

Posted: Sun Aug 17, 2008 7:27 pm
by aEx155
cantab wrote:What exactly do you mean by "a short tube with psi 100"?
One possible answer would be a short LRT tube layered a bunch of times to get it to 100 PSI (very unlikely). I guess if you did put in a rather short piece of LRT it would become sphere shaped, but I'm not sure.
11ilee wrote:Well, I read in the SuperCPS article that a CPS 2000 uses a pressure chamber with 45 psi, and that increased psi meant increased performance, (I may be wrong, I'm no expert on waterguns.)
I'm pretty sure that increasing pressure doesn't lead to a direct increase in performance; you'd need to do other things (like adding good nozzles and changing to an optimal nozzle size) to use that pressure fully. On another note, layering LRT (which is what is done to get higher pressure tubing) gets hard as more layers are added, so achieving 100 PSI would be a feat...

Re: Replacing a spherical pressure chamber

Posted: Sun Aug 17, 2008 7:49 pm
by cantab
Read the k-mod guide in the mods section of this website for the pros and cons of increasing rubber thickness. If you want a performance boost, a k-mod is the easiest way to do it.

As for replacing the PC, should you need to, you could always try making a bladder out of balloons. It's a pain to do but results tend to be quite good. I'm sure some people here have done it.

Re: Replacing a spherical pressure chamber

Posted: Sun Aug 17, 2008 10:58 pm
by Silence
100 PSI is excessive, I think. Flow/output increases as the square root of pressure, and range increases as less than the square root of flow. In the end, you're battling diminishing returns and you may only see 20% of a range increase. Also, more pressure means you pump with more force. I'm guessing it's already somewhat hard to pump the CPS 1500...it should be impossible with 100 PSI. And finally, the gun isn't meant to handle three times the pressure and it'll break.

However, you probably picked 100 PSI as an arbitrary goal, which is fine (but hard to measure). There should be no problem with 20-30 balloons if you're just looking for a modest performance increase. You *will* need to replace the chamber if you want more capacity, though.

Re: Replacing a spherical pressure chamber

Posted: Mon Aug 18, 2008 12:08 am
by DX
The CPS 1500 pc is one of the best and largest spherical pcs. I see no reason to replace it with anything else unless it's broken. You could even lose power if you replaced it with a weaker cylindrical one [unless you use LRT].

As other have said, replacing it with an all-balloon pc is possible and has been done. Results vary depending on how thick you make it - you could get performance similar to a light or moderate k-mod. However, it is indeed a pain, especially to get the first few balloons started, and isn't exactly the most durable thing. It's much easier to just k-mod the existing pc or if broken, swap in another spherical pc and k-mod that. 1500 pcs are easy to work with given the right mark combination. I think the 1500 [don't know if 1500s have marks] and 1200 mk1 swap effortlessly, but it's been a while since I last had a look inside either.