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Toothpick ammo?

Post questions and info about pneumatic (compressed gas) powered cannons here. This includes discussion about valves, pipe types, compressors, alternate gas setups, and anything else relevant.
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Toothpick ammo?

Unread postAuthor: randomvictim » Sun Jul 29, 2007 9:24 pm

I was thinking about making a pneumatic with a barrel small enough for toothpicks, but my concern is the toothpicks not going straight because they are so light and small. Would the air turbulence just make the toothpicks go in random directions?
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Unread postAuthor: mike1010 » Sun Jul 29, 2007 9:30 pm

not if you put a small weight on the back but what barrel is small enough for toothpicks? maybe really small breakline
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Unread postAuthor: randomvictim » Sun Jul 29, 2007 9:46 pm

I'm going to try to find a copper one, if I can't find a copper one then maybe some sort of hose. If all else fails, I will drill a hole through a piece of wood.

Would a bit of paraffin wax stuck on to the back weigh enough?
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Unread postAuthor: Modderxtrordanare » Sun Jul 29, 2007 10:12 pm

randomvictim wrote:I'm going to try to find a copper one, if I can't find a copper one then maybe some sort of hose. If all else fails, I will drill a hole through a piece of wood.

Would a bit of paraffin wax stuck on to the back weigh enough?


The wax might fall off, but I'd be willing to bet that if you rolled up a little bit of tape on the back until it fit in a 6mm barrel (for bbs) then the tape would stabalize it, and you'd have a good barrel too.

Or drill a hole in a bb and stick the toothpick through and glue it in.
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Unread postAuthor: Insomniac » Mon Jul 30, 2007 12:50 am

Actually what you want is to put a weight on the front.

To make a projectile stable the center of gravity has to be in front of the center of pressure. The further apart they are, the more stable the projectile will be. Adding weight to the front will bring the center of gravity foward, while adding fins or a cone to the back will move the center of pressure back. So a toothpick with weight at the front and tiny fins or a cone of some sort at the back will be a very stable.
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Unread postAuthor: mike1010 » Mon Jul 30, 2007 2:17 am

Insomniac wrote:Actually what you want is to put a weight on the front.

To make a projectile stable the center of gravity has to be in front of the center of pressure. The further apart they are, the more stable the projectile will be. Adding weight to the front will bring the center of gravity foward, while adding fins or a cone to the back will move the center of pressure back. So a toothpick with weight at the front and tiny fins or a cone of some sort at the back will be a very stable.


i didnt think of that with such a small light projectile you need weight on the front and drag on the back so even tape on the back would be fine but i think your really looking for good cheap amo as i am too i think a small piece of hot glue on the front and back might even do the trick and you could make it fit lots of sives of barrels. hope this helps :P
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Unread postAuthor: spud yeti » Mon Jul 30, 2007 10:25 am

You could mold the piece of hotglue (in the front of the tootpick) in the barrel and lube it to get maximum air efficiency and have a small cone at the back to add stability. nice idea though.
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Unread postAuthor: jackssmirkingrevenge » Mon Jul 30, 2007 10:38 am

Toothpicks aren't going to be very effective. In my pengun project I had a 2.5mm (0.1") caliber barrel, I found nails with their heads cut off and a hollow tail made of rolled up tape to be effective "darts" that flew straight and hit hard.

With a barrel that small however, the base area of your projectile is going to be tiny and you'll need high pressure (200 psi +) for good performance.
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Unread postAuthor: clide » Mon Jul 30, 2007 11:10 am

It takes a little messing around with, but once you get the hang of it you can easily wrap some scotch tape on the back end of the toothpick so that it makes a little hollow cone and then cut off the excess and unevenness so that it will fit in your barrel. It makes a very quick and cheap dart ammo for small bore guns.

I've shot these out of ~.28" barrels and they work very good. I could hit a dartboard from across the room and I still have one stuck in the ceiling right above my desk.

If you want to go a step further you can get some wire and wrap it around the front part of the toothpick and extend a little section of the wire forward out the front to act as a tip. The weight of the wire makes it fly better and the wire tip makes it much more reusable since the wooden tip of the toothpick tends to dull and break pretty quickly.
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Unread postAuthor: randomvictim » Mon Jul 30, 2007 3:54 pm

The entire idea about the toothpicks was that they were cheap and I could easily get a bunch of them. If I have to custom tailor each toothpick it defeats the purpose =(.
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Unread postAuthor: Big-mac » Mon Jul 30, 2007 4:33 pm

just use finishing nails with the heads chopt off.
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Unread postAuthor: dongfang » Mon Jul 30, 2007 5:15 pm

Hi,

I would look for aluminum tubing for a barrel. Here in Europe, any equivalent of Home Depot etc. has a selection of aluminum tubes of a decent quality (and at a killer price).

But as has been hinted by others, spud guns work best with a very low mass per cross section area of the projectile. For real guns, it's rather high, but for spud guns, pressure is low, so is projectile density (and so is range). A toothpick has a relatively large mass stacked onto a tiny area.

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Unread postAuthor: clide » Mon Jul 30, 2007 5:31 pm

The tape thing can be done quite fast once you get the hang of it, but if you don't want to modify the toothpicks then they would make lousy ammo.

If you want something small and cheap that doesn't need to be modified just use BBs or pellets.
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