simple homemade cps gun help

[Ben]

Colossus the chamber: http://www.sscentral.org/mods/colossus.html

Gluing rubber together again doesn't work from what I've seen. I've read a lot of people think of similar stuff to repair CPS bladders, but it just separates really quickly even with rubber cement. Get some mountain bike tubes. They'd have a much larger inner diameter that would definitely slide over your tube. If you go to bike shops and ask for some old tubes they often will give you a bunch for free (from what I've been told at least). Layering bike tubes should be very easy over your LRT because the mountain bike tubes' inner diameter is larger than the LRT's outer diameter, so no stretching is necessary.

[Commander Soakage]

I don't need anything w/ a bigger inner diameter, i need somthing w/ a smaller inner diameter. about 1/2 inch would be perfect

[Ben]

I was a little confused because you didn't distinguish between the two tubes, so I thought you had a road bike tube. Road bike tubes are smaller and should work fine for you.

Making the tubes fit tight isn't required and makes the process easier. It won't be as efficient as if the tubes were tight, but it won't be significantly weaker either.

Though, I just realized I was also confused about your tube in general. You said the diameter was 1/2 inch, which I read as 1/2 inch inner diameter. I can now tell that your outer diameter is 1/2 inch. In that case, this tube should get the pressure you reported before, but the flow would be extremely reduced due to the 1/4 inch diameter. It would be decent, but I wouldn't expect more than 45 feet of range from it at best. Your PC capacity also will be very limited from this very small tube. I would suggest ordering a new one from McMaster-Carr.

Edit: Also, if the OD is 1/2 inch, you might want something slightly larger anyway to let you slide it through. Otherwise you'll have to stretch the tubing to make it thin a bit so you can stick on the larger tubing.

Another option for Colossus again is LRT, but since you won't order from McMaster-Carr then that's not an option.

Go with road bike tubes if you want to keep the same piece of latex tubing. I don't know the exact inner diameter of road bike tubes, but it should be close at the very least.

[Commander Soakage]

I have started construction and so far it has gone well however, I need a check valve and home depot didn't have 1/2 inch. the smallest size they had was 1-1/2. does anyone know of a store that sells 1/2 inch check valves.

[Drenchenator]

Stock between Home Depot and Lowes can sometimes be complimentary. Ben and I usually go to Lowes for smaller parts and Home Depot for larger, because--at from my experience--Lowes has a better selection of smaller parts while Home Depot will have all the big pipe you need. Find a Lowes is what I'm saying.

[Commander Soakage]

thanks, drenchinator. my mom is about to take me to samon's (a plumbing specialty store) to buy check valves. one question though how much do 1/2 inch ones cost

[Ben]

You can check McMaster-Carr for current prices even if you don't buy it from them. McMaster-Carr has them at $7.10 each. Prices vary a lot depending on where you buy. I've seen them cheaper than that recently, but I wouldn't be surprised if you have to pay more.

Homemade check valves are an option, as are buying cheaper ones. However, since you've said you're not going to use McMaster-Carr, your only other real choice would be to build homemade ones unless that store has a good variety. We have a guide on building check valves in our homemade water gun section.

[Commander Soakage]

I checked out the homemade check valves diy, but I just found out they sell for 5.95 at lowes.
I think I might go w/ lowes just because I don't know were to find springs and car tire valves.

[Ben]

You should be able to find springs and schrader valves are both Lowes and Home Depot. Ask the people there if you need help. If you can find check valves though you don't need to, so don't worry about it.

[Commander Soakage]

I finished the gun. It works but it doesn't even match the HB for power the inner diameter is now more than before, so there is increased water flow. could one of you tell me which is the most likely of the causes below:

1. the hose barb is still somewhat less than 1/4 inch inner diameter.

2. I sealed the pump with duct tape, but it still pressurizes the chamber pretty well

3. the LRT now has less thickness than before.

I think it's probably #1 but i want to know which one it is before going out to a store.

[Ben]

It's probably a combination of all three and maybe something else, but your main problem is the tiny internal diameter. If you post some pictures of your water gun we could provide a better analysis. Until then, I'd suggest some larger LRT and a better pump. From larger LRT you'd also get the benefit of higher water capacity.

[Commander Soakage]

I think I may have solved the problem. but I'm still not getting quite enough range. What I did is I took the pc out of a nerf gun (it is an elastic chamber about the size of a FF's) and I modded It w/ bike inner tube. I think it is a good chamber but the range of a riot blast is about the same as the stream they are both about the same range as a HB. What should I do short of buying more LRT.

[Ben]

Why won't you buy any LRT online? Most of your problems would be solved if you bought some LRT.

You could use any rubber chamber. The ones Hasbro sells are decent, but not adequate unless you want performance matching what they sell. Bike tubes by themselves work too. Balloons work. We've already been through this from what I remember.

[Silence]

I'll back Ben up. Latex rubber tubing is cheap and more powerful than anything else you could get. I understand your parents may not be willing to buy it online, but it is for a pseudo-educational purpose. Better than buying a commercial water gun if you're interested in engineering.

[Ben]

I just remembered another potential CPS option. The reason why I didn't think of it before was that it's very uncommon.

Water bladder tanks are rubber chambers inside of a metal case. They should be available in most plumbing stores and maybe even most home improvement stores (With that being said I had not looked for them before and have no idea). I don't know much about how they are different than regular rubber CPS, but from what I know you can pressurize them. They've only been discussed here twice before from what I remember, and this is the most detailed post about them: http://forums.sscentral.org/t4669/

From what I remember, these tanks can cost like $30+ individually, but, they can be found for cheaper and they are strong, high flow, high capacity, and potentially high pressure devices. I know little to nothing about them so you will have to do your own research Commander Soakage. I assume their use is mostly straightforward once you find a plumbing shop that sells them. It should be as simple as attaching them to your water gun in place of the PC.