watergun idea possible?

[solar00]

I like to create an ideal cph watergun and was thinking the following.

- exceeding the cps3200 in capacity,
- exceeding the cps2000mkI in power
- exceeding the total pc volume of the monsterxl (2 liter)
- a range of nozzles. (5x, 10x, 20x, 40x, fan spreadshot)

For the capacity, using a portable camping shower or water tank(20liter) as a backpack might be an option.
To exceed the cps2000 power: LRT with a thick wall or LRT with extra bike inner tubes?
For 2 liter pc volume: LRT with large diameter or just an extra long piece of LRT but will this work?

Bicycle pump (pic) for pressurizing the chamber.

For the nozzles pieces of pvc or gardenhose filled with epoxy and drilled with holes of different sizes for the 5x,10x,20, one with 6 or 8 small holes for the spreadshot (and one plain piece for 40x) which can be switched. (doesn't have to be one single piece like a stock gun but has to be changeble)



Is this going to work or is it completely wrong?
If the weight of the gun(without the backpack of course) is about the same as a monsterXL it's ok.

And IF it's possible what will it cost to let someone else build this for me? (that would be even better)
Maybe I can place an order for something like this in the shop.

[Ben]

My SuperCPS design on the website already can do what you want.

To exceed the cps2000 power: LRT with a thick wall or LRT with extra bike inner tubes?

Two layers of LRT with some bike tubes as described by Killer 7 in his guide will provide much power than the CPS 2000, in fact, probably significantly more.

For 2 liter pc volume: LRT with large diameter or just an extra long piece of LRT but will this work?

I have some stuff in my latex rubber tubing guide about approximating volume. 15.5 inches of the piece of LRT I suggest in the SuperCPS guide should hold about 2 liters. An 8 inch piece will expand to approximately 24 inches and most people use more than 8 inches, so this isn't a problem at all.

I just realized however that my figures in the guide are off so I'll need to correct them. I didn't subtract the dead space that contains water that can't be shot out.

Bicycle pump (pic) for pressurizing the chamber.

Bike pumps pump air, not water, so they'll need to be modified to work here. They also have a much larger diameter than what you want for a high pressure water gun. As the diameter increases, so does the surface area of the pump head, which makes pumps harder when pressure is constant. The 5/8 inch diameter is good for higher pressures.

Not to mention that I'm sure modifying a bike pump to work here would be difficult. A regular pump is fine.

And IF it's possible what will it cost to let someone else build this for me? (that would be even better)

I'm not taking orders at the SSC store at the moment but I can figure out what I'd charge you for this and when I start taking orders again I'll let you know. Shipping to Europe from the USA would be expensive though so you might want to wait for someone closer to make an offer.

By the way, I've moved your thread to the homemade water gun forum.

[solar00]

Thanks for the information Ben

I did a search for materials today but these pvc parts are hard to find (in the Netherlands)
So I decided to use copper (15mm pipes) for this watergun (all parts including the valves are available in copper).
Which is a little easier because I don't need glue or cement.

Since Mcmaster Carr is the only one who sell LRT in small amounts (and in Europe nobody has ever heard of it) I'll place an order for it and wait for the shipment


I'll start with an APH and remodel it later on to a CPH, when the LRT shipment arrives.
Still have to figure out what to use as a APH Pressure chamber, which can can be mounted on copper tees.


However still have a few things I like to know.
First, Which tubing is usable from the APH to the watertank, can I use a piece of standard garden hose for this?

And I'm not sure how to construct the nozzles.
Does these endcaps with a hole drilled in it give a good concentrated stream of water or should I try something else like straws and screens (like in the stock guns)

And is 15mm a good size for the pipes/valves/connectors or is a smaller or larger size better (we also have 12mm and 22mm available)


It will become a watergun contructed completely of copper except for the PC's
I'll take some pictures during construction.

[Drenchenator]

Still have to figure out what to use as a APH Pressure chamber, which can can be mounted on copper tees.

If you're buying from McMaster-Carr, you could just buy a short section of 10 cm copper pipe with the needed fittings. That should work well for an APH. Keep in mind though that McMaster has so much stuff on the site, so look around for anything that you think could work.

First, Which tubing is usable from the APH to the watertank, can I use a piece of standard garden hose for this?

Any kind of tubing can be used, including garden hose. It only really has to transport the water from that tank to the gun, so garden hose works.

Does these endcaps with a hole drilled in it give a good concentrated stream of water or should I try something else like straws and screens (like in the stock guns)

This tends to vary but for the most part, no. End caps don't provide as good of a stream because the inner diameter goes from whatever the pipe is to whatever the nozzle is in a short distance. Conical or reducing nozzles are better for that reason.

Straws and screens help keep the stream together by improving laminar flow. The screens just slow the water down. You may see the term linear guidance walls around the site; this refers to straws. The straws divide the water up into many little streams, one per straw in fact. The idea is that a stream is more stable when it's smaller, so this allows many little streams to act as an overall larger stream. Both methods yield a more concentrated stream.

It's really a matter of choice as to what kind of nozzle you have. Most people just go with the hole in the end cap model, and it definitely gets good results. If you want better performance, by all means use straws or a conical nozzle; screens slow the stream down which does concentrate it, but also decreases performance.

And is 15mm a good size for the pipes/valves/connectors or is a smaller or larger size better (we also have 12mm and 22mm available)

For better performance, try to use 22 mm pipe for the section from the second check valve to the firing valve. This improves performance by allowing more flow because the pipes are larger.

Can't wait to see the pictures. Not too many people have made copper guns, so I'm anxious to see the results.

[solar00]

I've collected almost all the copper/brass parts needed for the watergun except for the pressure chamber(s), it was more expensive than I thought.

Unfortunately McMaster Carr doesn't ship overseas anymore so CPH is no longer an option. (and so are bladder repairs, hopefully the bladders of my existing waterguns hold out)

I'll stick to APH for the time being but still I have to find somthing to use as pressure chamber.

[Ben]

McMaster-Carr is not the only place to get LRT, so I wouldn't say that a CPH is no longer an option. McMaster-Carr works for people in the continental United States only. However, places like Primeline Industries ship worldwide and I'm sure there is a more local place that sells LRT. You'll have to do some research to find a place that will sell to you if you want to make CPH in the future.

[Silence]

Wasn't there a US-based service that can take shipments and redirect them to people overseas? You may have to pay more for shipping and handling, but at least it'll work. That service has been suggested for US-only contests and shipping, but I've forgotten the name.

Somebody here might be able to redirect the shipment too, but it'll be about the same amount of overhead either way.

[Drenchenator]

Aqua Flash found one such service several months ago. The topic is here.

[Silence]

Thanks, that was what I had in mind. I should have checked the stickies in the Marketplace forum, not in the Homemades one.

[solar00]

I e-mailed Primelineindustries and asked them for the distributor in Europe, there should be one in Germany.

Meanwhile I have started building the watergun, and the first raw model seems to work.
I used a bike tube as pressure chamber(just to test the gun) but it cracked quickly after too many pumps.
The pump itself is also not completely airtight but it's a very old piece of wood and the O-rings are too big for it, I'll fix that very soon
.

So what I need to do now:

Make the nozzle(s)
Buy a solar shower+backpack (now using a bucket for testing)
Get my hands on LRT.
Make an airtight pump.
The last steps will be a PVC pc to protect the bladder and carrying strap.

(of course the pump and LRT are the most important)

For a possible LRT alternative, there is Silicon tubing available in the Netherlands, is this usable as well? (It stretches 350% and latex 750% so I'm not really sure about this)

This weekend I'll post some pictures of it.

[Silence]

If they offer maximum stretch distances, I'm guessing that tubing is elastic and should be usable. The question is, how much pressure you can get out of a comparable silicone tube? If they have information about that (like McMaster-Carr does for latex tubing, for example 15 PSI for one tube), then you might have found a great alternative.

Kudos for being so dedicated to getting your water gun built! Hopefully Primeline will respond favorably and the rest of the build goes smoothly!

[aEx155]

I've never heard of "Silicon" tubing...did you mean silicone?

[solar00]

Originally Posted by aEx155

I've never heard of "Silicon" tubing...did you mean silicone?

Yes it's silicone (silicon isn't really flexible )

[Ben]

That's good that you've found a distributor! Let us know if they work out and let us know which distributor you're trying so we could recommend them to people in the future.

I'm not sure if silicone tubing would work well. The only way to know is to try it. From my understanding, it should be at least relatively constant if it expands. What matters is having a nearly linear force vs. surface area graph and latex tubing has that. If the tubing expands, the surface area increases while the force increases, and if they are nearly linearly related you have a constant pressure tube.

[Aurum]

Hey, another European building a Copper gun.

I know your going for a CPH gun and all, but i'd just like to point out a tip for APH PCs with Copper...

Most 0.5L bottles have an internal neck measure of 22mm. PERFECT for attaching to 22mm copper piping. just need to make it hold together, and it works nicely. Just thought i'd point that out for you