RPG (not dungeons and dragons you nerd)

[magnum9987]

THe shaft could be filled with propellent and the and the plastic bottle could be the projectile, it would be slightly more rocket-ish and would probably work better

[daberno123]

Bigbob used dry ice to pressurize the KAMG to 300-400 psi.

Check out the thread on it.

But that was a metal gun, I would never use dry ice with PVC because of the reason brogdenlaxmiddie pointed out

PVC + DRY ICE = BRITTLE PVC = BOOOM IN YOUR FACE

[magnum9987]

It is not in my interest to rip my arm off, or eradicate my hearing. MAybe ill just use a combustion system with the fuel stored in the shaft. again: ITl be more rocket-ish

[Rokmonkey]

Nope, can't rocket, only impulse.

[bigbob12345]

Bigbob used dry ice to pressurize the KAMG to 300-400 psi.

Check out the thread on it.

But that was a metal gun, I would never use dry ice with PVC because of the reason brogdenlaxmiddie pointed out

PVC + DRY ICE = BRITTLE PVC = BOOOM IN YOUR FACE

Yes I did and still do
There are many disadvantages to a system like that though, one being you have to unscrew something you just yanked in there as hard as you can which gets annoying.
Also dry ice is not something you can just pop intot the conveint store and get a block of, it is hard to find
And last dry ice is very excpencive, I only use it because I can get it for free.
And brogdenlaxmiddie making pvc colder actually raises its burst pressure by a decent amount, it is just more prone to cracking if you drop it. So if you are carful with it there shouldnt be any problem.
But dont quote me on that.

And now that i think about it, i really need to make a better video of it

[magnum9987]

Here is the basic idea. The shaft is about 20inches long. The gas chamber is designed to also be a sort of buttstock. Before the trigger/ grip is a plexiglas shield to protect the user from the gases. the tip of the shaft is sanded down to fit inside a plastic bottle. A

[magnum9987]

Idea update

Couldnt the fuel be given a small increase of pressure inside the bottle giving it a little more umf?

[Sticky_Tape]

like a hybrid I don't think you should try that.

[magnum9987]

big boom? Too dangerous?

[Sticky_Tape]

you said the high posibility.

[magnum9987]

Oh. But other wise i think it could work same principle as any air rocket you've seen as a kid.

Oh and the new avatar is hilarious.It reminds me of an old friend who reminds me of Gollum from LoTR

[Fnord]

If you're going to use water to evaporate dry ice it can be done safely* in pvc, but you have to know what you're doing. You need to get the water warm enough to compensate for the cooling effects of Co2, and either monitor the pressure or calc how much gas you'll get per gram of dry ice. A pop-off valve is a must.

Metal is a really good idea though. If it were my design I'd just use a piece of 3" conduit with a nice thick cap on one end. That way I could just throw some dry ice in a soda bottle as a "propellant charge" and load it in behind a projectile. Kind of like a dangerous burst disk mortar.


*relatively safely

Oh and the new avatar is hilarious.It reminds me of an old friend who reminds me of Gollum from LoTR

The sad thing is, I have that picture. Yes, I've covered that much of the internet.

[THUNDERLORD]

Just stuff a whole bunch of dry ice into atlest a 4-6" pipe and some little hot water and hang on that would be cool. Just make a video, I will buy a copy. 8)

[psycix]

Just stuff a whole bunch of dry ice into atlest a 4-6" pipe and some little hot water and hang on that would be cool. Just make a video, I will buy a copy. 8)

Could you describe what you mean?
If you put dry ice in an open pipe along with hot water, all you get is alot of white CO2 "steam".

[magnum9987]

I've given up dy ice. I realize that i know no one who can get me dry ice. I think a HUGE combustion chamber (5in diameter?) would generate the huge amount of gas to propel the bottle sufficient distance. Like I said earlier, the combustion chamber would do a 90 downwards and make a butt stock. And I think I should add a plexiglas heat sheild to protect me from back blast from the pulse. As well, i think ill use a bbq ignitor, its the cheapest option for me (Stun gun is out of the option for price and me being a minor)