You just need a regulator. If you run CO2 in PVC, sometimes it is a good idea to have an expansion chamber, but in copper, it really isn't necessary. The regulators block most of the liquid CO2, but sometimes a little gets through.

Potassium nitrate (the exact same thing as salt peter, it's like saying sodium chloride for salt) is water soluble, as is sugar. As long as you don't let it catch on fire, then you can just let it soak in the pot and it will all dissolve away. Then your pot is fine.

If you don't run a regulator, you will blow up your cannon. Check here http://www.palmer-pursuit.com/online-ca ... female.htm

If you take it up to 120psi, you can calculate it in the CO2 sticky in the pneumatic section. Just check my post at the end. If you are really fixated on the 100 psi, then go here http://en.wikipedia.org/wiki/Ideal_gas_law and follow the instructions. Be sure to convert everything to the right units...

GalFisk- Do you know of any places where I can get a bag of KNO3 fertilizer? I've poked around locally, and can't find anything. I'm not sure , but I remember hearing that they stopped carrying KNO3 as a fertilizer.

Just how much did this cost you to make? And how much did your dad help pay for it? btw, sweet cannon. I had about the same reaction as in the video... HOLY SH!T

Make sure that the valve is on the right way (sounds dumb, but seriously check it.). Grease where the diaphragm and the seal to the barrel meet. This helps make a better seal.

Oooh, good catch kenny. I completely missed that. Make sure you post results of your experiments, I'm very intrigued. Make sure you write how you mixed the mixture (i.e. dissolved in water, dry, or melted together)

Yeah, they have it at my Lowe's too. Copper can be pressurized pretty high, I believe to around 500 psi. I'm kinda confused, are you using 2" copper pipe in a paintball cannon? That'd be pretty heavy.

Ammonium nitrite, if I remember correctly, is a MUCH stronger oxidizng agent than KNO3. I.E. The Oklahoma city bombing, fertilizer bombs, etc. Ammonium nitrate can also more readily react with common substances than KNO3 which can make it seem unstable. Although sugar and starches are both in the sa...

Kenny- I'll make a video of myself eating some of it :lol: Theoretically, I could (It was put in the armies food suply to stop them from getting boners for petes sake!) because it is non-toxic. I wouldn't do it with the stump out though! KNO3 is not a dangerous chemical at all. IT IS IN TOOTHPASTES ...

If you don't want fire, I'd not go with this. You could maybe put it in a steel can, but not an aluminum one. Makes aluminum disappear. You could maybe use a steel can with a lid with holes in it, but you would still have to worry about fire.

If you wanted it to burn faster, you could probably just up the amount of saltpeter to the amount of sugar. I think that using multiple fuses works better, though. You get more smoke in a shorter time. Oh yeah, I forgot to tell you, regular old hobby fuse will light this. The green "safety fuse" tha...

I hope you mean powdered sugar, as in finely ground up sugar crystals, and not powdered sugar as in "baker's sugar" because that stuff is mixed with corn starch.

It is good for paintball smoke screens, but it burns really hot and can't be thrown near people. Other than that, yes it makes GREAT paintball smokescreens.