9 replies to this topic

[Gengar003]

Hello... I wish to make a homemade pump gun shoot from 2 barrels simultaneously, with ranges around 50-70 feet.

When deciding what to use for an air tank, and how big that tank should be, I remembered the AT2K tank and thought "heck... this is at least as big as that, and I'd be fine with half an AT2K's range"

So, before I assemble everything, my question: In your opinion, would an air tank of this size be sufficient to fire two darts in two barrels 50-70 feet? If not, how big should it be? (Those are 3/4" PVC elbows)



I jury-rigged it together with hot glue and electrical tape, and after just one or two pumps it got very hard to pump... by the time I could get my hands off the pump and to the trigger, however, most of the air had leaked out, so I was not able to ascertain on my own if this tank was sufficient.

Additionally, I'm currently just hooking the tank up to the air pump... I searched the homemade forum a bit and saw "check valves" mentioned -- would it make sense to have one, given that I intend to use a storebought pump?

Edited by Gengar003, 15 January 2007 - 09:04 PM.

[monkey with a nf]

it's leaking becasue hot glue isn't airtight. You'll need to use plumber's goop or epoxy (I think). I'm pretty sure that PVC cement (w/ primer) works too.

[Gengar003]

You misunderstand -- I'm not asking for help with leaks; I know that hot glue leaks. What I want to know, before I epoxy it together, is if the size of the tank looks okay. As this is my first homemade, I have no idea, but I'm hoping other, more experienced people will.

[Substance Abuse]

As this is my first homemade, I have no idea, but I'm hoping other, more experienced people will.

For your first tank it looks pretty good. It looks Like It would possibly fit with some cutting of some plastic.

Nice work.

[Langley]

It depends on what you're using for valves. What's the rest of the thing look like?
Your best bet with pumps is actually to use a nerf gun pump from an at2k or another easily found gun. Nerf gun pumps already have a built in check valve, they've got the right ratio of length to diameter for the pressure and volume of air you're looking for, and the hose nipple is just the right size.

[Gengar003]

I do not have any spare pump gun parts lying around. I was hoping to just use a bicycle pump connected to the tank, relying on the pump's built-in valve. Is that a bad idea?

[Prometheus]

This is some very basic physics, so anybody with a GR.10 education should be able to follow this. Any mod or somebody intelligent, like CS will tell you that volume is somewhat important, but so if pressure. If you were to take that tank, and double the volume, but cut the pressure in half, you have them same volume of air. Period. So yeah, lots of volume is great, but if you have lots of pressure so is that, Any serious homemade-compressed air person will tel ya that pressure is just as important as volume, because then that helps determine if you need a regulator or not. And one more thing, some bike pumps do up to 60 psi, ans some only 40, so it really depends on what type of pump you are using.

[Gengar003]

If I used a separate check valve between the tank and a pump, would I be able to pump the tank to more than the bike pump's maximum PSI? Common sense says "no," but then again, I've never done this before.

On the other hand, Prometheus, if the volume is too little, all the pressure in the world won't help (well, maybe if you had all of it, but you get the idea) because there's too little actual air moving, nevermind how fast or at what pressure.

It sounds like the verdict is "Yeah, that tank is big enough," so I guess I'll soldier on. Thank you guys.

[Prometheus]

To your first point, no, because when that check valve opens, a pressure equilibrium will be maintained between the pump and the pressure tank. And to your second point, true, but that would have to be a rediculously small tank....

[mrgrimm]

Hello... I wish to make a homemade pump gun shoot from 2 barrels simultaneously, with ranges around 50-70 feet.

When deciding what to use for an air tank, and how big that tank should be, I remembered the AT2K tank and thought "heck... this is at least as big as that, and I'd be fine with half an AT2K's range"

So, before I assemble everything, my question: In your opinion, would an air tank of this size be sufficient to fire two darts in two barrels 50-70 feet? If not, how big should it be? (Those are 3/4" PVC elbows)



I jury-rigged it together with hot glue and electrical tape, and after just one or two pumps it got very hard to pump... by the time I could get my hands off the pump and to the trigger, however, most of the air had leaked out, so I was not able to ascertain on my own if this tank was sufficient.

Additionally, I'm currently just hooking the tank up to the air pump... I searched the homemade forum a bit and saw "check valves" mentioned -- would it make sense to have one, given that I intend to use a storebought pump?

it looks vary funny. i belive it will work, if you would of used PVC cement. it holds with an air tite seal and it looks cleaner.