27 replies to this topic

[Grimm]

Okay, I need something. Does anyone know how to make a homemade bladder? I read something about making them out of bike innertubes in the semi-auto 2k topic, but it did not explain clearly. Could someone tell me how that's done? Thanks in advance.

[CaptainSlug]

A bike inntertube would be far too thin. Making your own bladder tank is no easy task and I'm not sure what material the stock bladders are made out of. It's probably latex or butyl rubber.

Edited by CaptainSlug, 26 November 2006 - 10:56 AM.

[Substance Abuse]

A bike inntertube would be far too thin. Making your own bladder tank is no easy task and I'm not even sure what material the stock bladders are made out of. They're probably latex but I'll have to research it further.

I heard someone say you could make bladders out of 4 in PVC. Am I wrong?

[Grimm]

Perhaps I can layer multiple bike innertubes together. Though, once again, I'm not sure how to do any of this. Apparently it's no small task.

I heard someone say you could make bladders out of 4 in PVC. Am I wrong?

Sounds fishy to me. A bladder is supposed to regulate the amount of air that goes out per shot--I don't see how PVC can do that. Perhaps they were saying you can use 4 in. PVC as casing for the bladder? Or maybe they meant they were using the PVC to hold air, then go to the bladder (like that guy with the backpack and powerclip).

Edited by Grimm, 26 November 2006 - 11:07 AM.

[CaptainSlug]

I heard someone say you could make bladders out of 4 in PVC. Am I wrong?

I made a rigid wall tank as a replacement for the stock bladder. But PVC doesn't qualify as a bladder.

A bladder is supposed to regulate the amount of air.

The difference between a bladder and a rigid wall tank is the tank pressure drop-off rate. As a bladder tank empties (in terms of volume) it constricts, and the pressure level evens out a bit. So the volume of a bladder tank drops off at a faster rate than the pressure level. This equates to a more efficient tank design for this particular application.
The disadvantage of a bladder is that the materials you would use to make a bladder tank are not rated for the higher pressures that rigid tank materials are. That and they're harder to make.
The materials needed are potentially more expensive as well since you'll need some tubing that has a minimum ID of 3/4" and OD of 1" and the fittings for that size tubing can get expensive and difficult to find.
I'll see if I can come up with a part list.

Edited by CaptainSlug, 26 November 2006 - 11:13 AM.

[Flaming Hilt]

There's something at a hardware store kind of like vinyl (or some kind of stretchy) tubing. I don't remember what it's called; it comes in short segments between 1 to, say, 10" depending on the diameter of the tubing. Hose clamps included.

I just don't remember what it's called. Elf might. He introduced me to them

Anyways, I haven't tried them out yet because they aren't that stretchy, but I think maybe it's worth a shot.

[CaptainSlug]

Your local hardware store is not likely to stock the sizes of tubing you would need to make a bladder tank. Here's a potential list of parts I made. These are just for the purpose of suggestion to point you in the direction of what is basically required to make a bladder tank.

Mcmaster parts
5234K88 - Super Soft Latex Rubber Tubing 3/4" Id, 1" Od, 1/8" Wall, Opaque Black - $3.24 per foot
4596K42 - Thk-Wall Dark Gray PVC Threaded Pipe Fitting 1/2" Pipe Size, Cap, Schedule 80 - $2.10
4596K52 - Thk-Wall Dark Gray PVC Threaded Pipe Fitting 1/2" Pipe Size, Coupling, 2-1/32" L, Schedule 80 - $1.92
5463K254 - Nylon Single-Barbed Tube Fitting Barbed X NPT Male for 1/4" Tube Id, 1/2" NPT, Black - 10 for $4.52
7329K16 - Wide-Band Self-Tightening Spring Hose Clamp for 1-1/16" Hose Od - 10 for $5.98

And you'll need two larger brass barbed tube fittings from http://www.fittingsa.../malpiptap.html or a local hardware store. You need
MPT-12-8 - Brass Multi-Barbed Tube Fitting for 3/4" Tube ID, 1/2" NPT - $1.49 each

Put that all together with some teflon tape on the NPT threads and it should work as a drop-in replacement for any stock bladder. For safety it would be best to mount it inside of a length of pipe.

Edited by CaptainSlug, 26 November 2006 - 11:39 AM.

[Grimm]

Alright, I will try it out. Thanks, and I'll tell you all how things turn out when I'm finished. Planning to mount in pvc when I'm done, probably with some sort of clip system that will be fabricated out of balsa.

Edited by Grimm, 26 November 2006 - 11:44 AM.

[Forsaken angel24]

When I was at the hardware store recently I found an interesting peice in the plimbing section for about $3. It is rubber and has about the same thickness as the stock bladders however the shape is funky.

It had 4 sections each going up one size larger than the next. It had a clamp around each section

````---
````--- <Clamp
````---
```````---
```````--- <Clamp
```````---
``````````---
``````````--- <Clamp
``````````---
`````````````---
`````````````--- <Clamp
`````````````---


Now if you could find a way to attach it and make it airtight then I think it should work.

( I officially hate trying to illustrate things in forums.) The image didn't come through as I wanted it to so I have shown you an image of tubing cut in half vertically.

Edited by Forsaken_angel24, 26 November 2006 - 12:30 PM.

[Doom]

About 25% of my PMs and a lot of my posts are about latex tubing. It's about time someone other than myself suggested McMaster-Carr. Thanks a bunch CaptainSlug.

I don't know why you'd go with anything else personally. Two years ago I built a homemade Nerf gun that used latex tubing and it worked great except for the repeating motion, which has a tendency to jam (not that anyone cared even back then). Latex rubber tubing is cheap and fairly powerful. I tried telling people that LRT is better for experiments and modifications in a thread about semi-auto AT2Ks, but apparently I came off on the wrong foot and no one seemed to care about LRT. After that I pretty much assumed no one cared, but it seems more and more people do actually care.

If you wanted to go further, you could buy some thicker tubes. McMaster-Carr's selection isn't that great, so you might have to try some online manufacturers such as Primeline Industries. Expect to order a lot of tubing at expensive prices though.

For the water gun people I'm planning on ordering some thicker tubes myself to resell, but these tubes would not be right for Nerf guns because the ones I'm ordering have a lot of force, not necessarily pressure. Pressure matters in Nerf guns because the surface area of the back of a Nerf dart doesn't change that much between guns, so the force on the dart is dependent on the pressure. If someone here is interested in ordering some tube for Nerfers, I would highly suggest it. They'd need to know which tubes to order though, and I haven't quite figured out the pressure formula based upon the ID and wall thickness of a tube. All you need is a tube with a thick wall and fairly small ID to get a lot of pressure (force distributed over a smaller area equals more pressure). The thickest 3/8 inch to 5/8 inch ID tubes are what you're looking for.

If you have the money it probably would be better to make a big rigid air tank in a backpack and regulate the air output. That'd get you more pressure more easily with more common parts. Rubber tubing really is better for small things and water guns.

Hope this helped. Let me know here if you have any questions about latex tubing because I would be a good person to ask. There's also a small forum dedicated to the subject: http://primeline.skylan.net/forum/

[Grimm]

If you have the money it probably would be better to make a big rigid air tank in a backpack and regulate the air output. That'd get you more pressure more easily with more common parts.

I will try this, but it seems large and clumsy. For now, I will work on this idea and see if I can make the bladder by using tubing. Perhaps if someone bought tubing in bulk, we could all buy a foot or so for a price (the same way PETG is sold).

Edited by Grimm, 26 November 2006 - 01:28 PM.

[CaptainSlug]

It's not the tubing that's expensive ($3 or $4 per foot for the thicker wall stuff), it's all the other parts you need to plug the ends of the tubing and keep the plugs in place that add the most to the price. Any kind of large capacity tank it going to cost atleast $20. It's much easier and generally cheaper to build an effective rigid wall tank because you're not trying to control an elastic medium.

And Nerf guns typically only need 10psi to fire a dart 90 feet. Excluding the guns with pneumatic actuators that operate at a higher pressure level.

Edited by CaptainSlug, 26 November 2006 - 02:26 PM.

[Doom]

I will try this, but it seems large and clumsy. For now, I will work on this idea and see if I can make the bladder by using tubing. Perhaps if someone bought tubing in bulk, we could all buy a foot or so for a price (the same way PETG is sold).

Rubber tubing is fine for what you're doing. I mainly mentioned regulated air pressure because if you want more power, it would be easier to do and cheaper than similarly powered rubber tubing (at least if you buy all of that tubing in bulk)

Edited by Doom, 26 November 2006 - 04:04 PM.

[elf avec gun]

There's something at a hardware store kind of like vinyl (or some kind of stretchy) tubing. I don't remember what it's called; it comes in short segments between 1 to, say, 10" depending on the diameter of the tubing. Hose clamps included.

I just don't remember what it's called. Elf might. He introduced me to them

Anyways, I haven't tried them out yet because they aren't that stretchy, but I think maybe it's worth a shot.

They were Next to the couplers... I think that these ones were called rubber extension couplers or something like that... they had two clamps, one on each end. They prob wouldnt work. They all looked like they were too wide.

HAhah 'elf introduced me to them'
Flaming Hilt meet extension coupler, extension coupler meet Flaming Hilt...



Just sit around and wait for Piney, I have a hunch that he might know what they are. But that is assuming that they are for PVC.

[urbanfighter7]

latex rubber tubing!

[nerfboi]

I remember seeing a homade that was pump action and I saw a mountain dew 2 liter bottle on it.
So im guessing you could use a soda bottle as a blader

[King Of Butt Land]

Your retarded. Not to flame but I wouldn't give people advise that is not legit.

-Butt

[Dart Attack]

A bottle would just Break

Edited by Dart Attack, 18 February 2007 - 04:01 PM.

[nerfboi]

Ok I was just throwing ideas out sorry.

[sam]

Actually pop bottles can hold around 120psi. I wouldn't put that much in them but they are usable as airtanks. Carrtoon modded his AT3K so that it was semi-auto using pop bottles. The bottles had schrader valves on the caps so that he could switch bottles really easy. He got about 4 shots from a 20 oz. bottle and about 8 from a 2 liter.

[nerfboi]

Actually pop bottles can hold around 120psi. I wouldn't put that much in them but they are usable as airtanks. Carrtoon modded his AT3K so that it was semi-auto using pop bottles. The bottles had schrader valves on the caps so that he could switch bottles really easy. He got about 4 shots from a 20 oz. bottle and about 8 from a 2 liter.

AHA!!! I told you!!!

[Retiate]

Actually pop bottles can hold around 120psi. I wouldn't put that much in them but they are usable as airtanks. Carrtoon modded his AT3K so that it was semi-auto using pop bottles. The bottles had schrader valves on the caps so that he could switch bottles really easy. He got about 4 shots from a 20 oz. bottle and about 8 from a 2 liter.

AHA!!! I told you!!!

But he was looking for a bladder, not an air tank. But I like that bottle idea...

[Prometheus]

Ok, just to clarify what stuff really is. Bladder - think of where your piss is, and how it feels good when it all comes gushing out. Ok? it's expandable. I've never seen an expandable pop bottle. That would be called an air tank. And whoever said that the bottle would break - just go hide in a corner. Wikipedia has detailed info on pop-bottle rockets, and various pressures used. 60 psi will not break a bottle, unless it has been previously damaged.

[Flaming Hilt]

I recently talked to my dad about this; he's an engineer. He suggested building an accumulator.

What an accumulator is is a tank that is always pressurized via air or a spring. Inside of this tank is your bladder.

How it works: the accumulator is always putting pressure (say 30 psi) on your bladder. Your bladder will not expand ridiculously until it can overcome the pressure in the accumulator. It's hard to explain how, but because of this, the pressure in the bladder will jump to 30 very fast and stay there for a long time.
IE:
1 pump -- 15 psi
2 pumps -- 28 psi
3 pumps -- 29 psi
4 pumps -- 30 psi
5 pumps -- 30.5 psi
etc. etc.

This helps because with a regular bladder, the pressure would advance at regular intervals:
1 pump -- 5 psi
2 pumps -- 10 psi
3 pumps -- 15 psi
4 pumps -- 20 psi
5 pumps -- 25 psi

until it burst.

This HELPS because then all your shots go equal distances. The last shot will have less air, but because it's in an accumulator, have just as much pressure as the first.

And that's how it works. So basically, make a PVC tube for the accumulator, run some latex tubing through it as the bladder, and then seal and pressurize the accumulator.

Otherwise, just latex tubing is what I suggest... but without an accumulator, the distances of the shots will vary greatly (as seen in a MS or PC).

[elf avec gun]

FH THAT'S BRILLIANT!!!

Does anyone else feel stupid for not having thought of that?

I know that you and your dad aren't on the best of terms, but I would still like to meet the guy sometime.