I found this in INTFIOTW, and thought it was cool but a bit overpriced for what it actually does. I think it can be made more cheaply.

http://gadgets.boingboing.net/2008/06/16/wasp-injector-knife.html

Im thinking just drill out a knife blade and mount in on an airsoft pistol, bayonet style, then somehow connect the hollow column to the CO2 outlet and mod the gun to release a continuous stream.

Dude, this is a fucking good idea... Plus it wouldn't be too hard to pull off. The biggest bitch of the design would be getting the channel in the blade, but that still wouldn't be too difficult.

All you would have to do is find a knife with a big enough handle to hold a CO2 cartridge and rig up a nice little button connected to a valve. Once you have the handle all ready, you could work on the blade, or simply attach a small copper pipe to it, cutting it at an angle to make it sharp.

From there just Stab, Press, Post Pics. ^_^

On another idea... If you're really lazy, just stick the aforementioned pipe on the CO2 cartridge and stick a dowel, sharp on both ends and slightly longer than the pipe, in the pipe. When you stab, it should puncture your enemy's skin then punch through the CO2 cartridge once it hits enough resistance.

Drilling the hole would be difficult. If the bit ends up snagging on a chunk of the steel and jams, the torque will snap the bit in half, and will be impossible to get out. It's happened to me alot of times, and I was using high quality bits too. You might be better off cutting a groove in the spine with a cutting disk, then sticking a small copper rod in there, weld the groove shut, then yank the copper rod out.

I think that would work just about perfectly, thanks for the idea.

hmm..

If I were doing this, I would have it set up to where you stab, hold down a lock release, and twist the handle to open the valve. This would insure you don't accidentally discharge the C02.

The blade..Does it really need to be a blade, per se? Couldn't it just be a hypodermic shank of some sort? Maybe something with a bowhunting broadhead epoxied on the end on it for extra holding power.

The blade..Does it really need to be a blade, per se? Couldn't it just be a hypodermic shank of some sort?

It doesn't seem like it has to be a blade, but I'm not sure if it's intended to be used as a knife as well. I don't really know how shark attacks go down, maybe you have time to see what's about to happen and whip out a blade, or they're fast enough that one could potentially sneak up and chomp down on you before you can react.

Wow, thinking about sharks eating you is kind of scary.

Initially I was thinking this would work for all large predators, even terrestrial ones such as bears, but taking the properties of water on pressure and the thickness of sharks' skins, I'll bet if you did this to a bear you'd end up with a very bloody, angry bear. So nobody use it on land!

It doesn't seem like it has to be a blade, but I'm not sure if it's intended to be used as a knife as well. I don't really know how shark attacks go down, maybe you have time to see what's about to happen and whip out a blade, or they're fast enough that one could potentially sneak up and chomp down on you before you can react.

Wow, thinking about sharks eating you is kind of scary.

Initially I was thinking this would work for all large predators, even terrestrial ones such as bears, but taking the properties of water on pressure and the thickness of sharks' skins, I'll bet if you did this to a bear you'd end up with a very bloody, angry bear. So nobody use it on land!

Judging by what happened to this poor watermelon (http://www.waspknife.com/video_watermelon.php) I dont think a bear would be much of a problem.

Judging by what happened to this poor watermelon (http://www.waspknife.com/video_watermelon.php) I dont think a bear would be much of a problem.
Lawl.

Judging by what happened to this poor watermelon (http://www.waspknife.com/video_watermelon.php) I dont think a bear would be much of a problem.

Bear > Watermelon

Seems like it's big advantage underwater is that it makes the shark float up and experience blinding pain, and the blinding pain alone might drive the bear to shred you to pieces faster. Also, with no water pressure, the bear might just kind of get a hole blown in it's side as the gas tried to escape. Dunno...

A chunky, bloody explosion would really suck. Obviously people's lives > bears lives, but shit man, think about getting stuck with this. You'd just fucking explode.

Oh, OP, if you build this, you must test it on a hefty [freshly] dead mammal and report results. I'm thinking it will make a chunky explosion or the air will find its way out through other holes [mouth, nose, eyes, ass, etc]. I'd suggest you do it with a 10' pole and a blast shield, just in case.

Bear > Watermelon

Seems like it's big advantage underwater is that it makes the shark float up and experience blinding pain, and the blinding pain alone might drive the bear to shred you to pieces faster. Also, with no water pressure, the bear might just kind of get a hole blown in it's side as the gas tried to escape. Dunno...

A chunky, bloody explosion would really suck. Obviously people's lives > bears lives, but shit man, think about getting stuck with this. You'd just fucking explode.

Oh, OP, if you build this, you must test it on a hefty [freshly] dead mammal and report results. I'm thinking it will make a chunky explosion or the air will find its way out through other holes [mouth, nose, eyes, ass, etc]. I'd suggest you do it with a 10' pole and a blast shield, just in case.

you post like a faggot.

you post like a faggot.

stfu acolyte

you post like a faggot.

Thanks man, that's the first time anyone's said that!

Dont drill the holes into a blade :P

Get 2 pieces of 1.5mm steel, and a few off cuts. Make a mockup of the blade using some of the steel, leaving a central chamber. Then braze the 2 pieces on either side. Then make a handle to store the co2 canister, and do some other tricky shit and walla, a $20 wasp knife.

Not 100% on how to get the co2 out whilst still having a functional knife, maybe it's not supposed to.

what you could try is making the blade out of ceramic. You could out a channel in the blade and then fire it in a kiln. I don't know how well it would react to the air pressure passing through it, but ceramic knives, when sharpened properly, have razor sharp edges. (And plus they pass through metal detectors)