"Requiem", my first homemade... made from Copper!

[Aurum]

Extra side note regarding copper PCs...

im seeing dual PCs made with 28mm piping blanked at one end.

and instead of keeping the gun a cross between 15mm and 22mm, to keep pressure at max (its metal, it can take it!), i could look at largely using 22mm and 28mm.

but i'd rather build this upped-model separately than upgrade the old one. I mean, i'll need something to use in the mean time right?

[Drenchenator]

28 mm seems a bit small. Regardless of how many chambers you are going to build, how much total water would you like in the chambers? To get about 500 mL of water--which is a good amount--you would need a chamber 81.2 cm long to just hold the water, let alone the air needed to propel it. If you can get it, I'd recommend copper pipe with a greater diameter for this project, at least 5 cm or greater if possible.

[Ben]

I'll have to agree with Drenchenator. 50, 80, or 100 mm pipe would be best for this because you can get so much more water capacity. If these pipes are too expensive I would suggest looking for scrap or asking if where you buy has any scrap.

You also could use something else for a pressure chamber. A bottle is common, but you might want to use latex rubber tubing, which has the advantage of being a CPS. If you do use latex tubing though you'll want to keep the smaller 15 mm pipe for the PC and valve end because the latex tubing has a smaller ID.

[Aurum]

Well, its going to be a plastic litre bottle first either way, the 28mm copper PCs were just an idea for once ive gbot it working.

28mm is kind of the biggest you can get for Copper piping (and is MUCH more expensive). I'll see if i can get my hands on some kind of Copper Tank, maybe like the ones used for boiling water in many many years ago, like one the size of a 3 or 4 litre bottle. the problem there being that the PC would then be too chunky.

I'll look into CPS tech now, perhaps i could contain the rubber bladder in a section of 15 or 22 piping then?

[aEx155]

Putting the bladder in 15-22 mm piping would greatly decrease the volume that it would be able to hold. Plus, I don't think the LRT tubing would even fit into the pipe. For bladder housing, it would be best to use something with a large ID (around 7.2-9.6 cm) like PVC pipe or soda bottles. You could use PVC for pressure chambers if you can't find anything copper that's large enough.

[Aurum]

Well, tbh, i wan the final, Final, product to be fully metal, with an attaching pressure gauge, as im looking for extremely high pressure to counter the weight of the metal.
Basically, the final version will be fully metal to that it take larger amounts of pressure than PVC can, and hey, maybe i'll start a new craze? lol

I heard somewhere on this size that LRT tubing should expand more in length than width, so surely I could have a CPS tube running along the underside of the barrel, as length would be more important than width?

OK, I think I'll stick with plain old APH, with maybe 1 or 2 PCs in the final design.

Ladies and Gentlemen, i begin construction tomorrow. Any last words before i log off for the night?

[Ben]

Well, tbh, i wan the final, Final, product to be fully metal, with an attaching pressure gauge, as im looking for extremely high pressure to counter the weight of the metal.
Basically, the final version will be fully metal to that it take larger amounts of pressure than PVC can, and hey, maybe i'll start a new craze? lol

If you're going for high pressures (60 psi+) then LRT wouldn't be the right thing to use. getting higher pressures is difficult with LRT. I'm sure you could get pressures as high or higher than 60 psi, but it would take more work than using simple air pressure. You should probably stick with a plain old APH as you said. You can always experiment later.

I heard somewhere on this size that LRT tubing should expand more in length than width, so surely I could have a CPS tube running along the underside of the barrel, as length would be more important than width?

Length doesn't affect pressure. As I said in my LRT article the tubing first expands in width and then length. If you limit the width it will reduce power slightly. I'd suggest at least a 3 inch (7.5 cm) diameter tube for the "standard" tube mentioned there.

[Aurum]

Thanks very much, and so, APH it is. Goodnight all

[Drenchenator]

If you really want high pressures, you're going to have to go with metal for the whole thing. I wouldn't trust a plastic bottle; copper metal seems to be a lot better for taking some pressure. Just an afterthought.

[aEx155]

From what I've seen, plastic bottles can go up to 100 PSI; I don't think that that would be achievable with anything pumped by hand.

[Drenchenator]

I was talking about really high pressures, 150 psi or more. It's possible, just not easy to pump it up to that high. If the pump shaft diameter is small, it shouldn't be too hard, just time-consuming.

[aEx155]

Correct me if I'm wrong, but at that pressure, wouldn't the stream break up easier because it's moving so fast?

[Silence]

It depends. That can happen easily on small CPS guns that have been K-modded to really high pressures. The problem is that the bore and nozzle aperture are way too small. Larger water guns are much more capable of handling higher pressure, although you'll still need good nozzles and even then there may be some turbulence.

Water cutters and jet cutters, which shoot streams of water less than a millimeter wide at thousands of PSI, exemplify the problem. At low "ranges" (say, within a few inches), the stream is really fast and coherent. But if you go any farther, it turns into a spray or a mist.

Similarly, too low pressure with too wide a nozzle doesn't work well. The end result may be like lobbing water out of a bucket. In the end, there is a balance and larger nozzles tends to help with greater pressure (like with a fire hose), even if you sacrifice a smooth stream.

But to answer your question, it really depends. In my opinion, a bad nozzle (and I only have bad nozzles) will do poorly at any pressure, and with luck the pressure won't be too high for a good nozzle.

[Ben]

Not necessarily. There's a certain size of stream for every velocity that will maximize range by minimizing break up while still having high enough velocity.

Edit: Didn't see SilentGuy's more detailed post.

[aEx155]

Okay, I understand now. Good nozzle + good stream size + high pressure = great ranges (right?)

Even though it would be possible, I don't think anyone would be willing to go up against 150 PSI of water pressure. I mean, it's going to hurt, isn't it?

Then again, with a larger stream, it wouldn't....

I guess a high soak factor + range would equal higher pressures + large nozzles, so if that's what Aurum is going for, then plastic isn't going to be enough...

...but for something simple with pressure that isn't too high, then it would work.