Everyone knows the COB, a 12 gram CO2 cartridge usually filled with a LE. I wanted to discuss all the variations of these, what they can be used for, and the best or easiest methods of construction.


How to make

First they have to be empty. If you don't have a gun to empty them in, lightly tap it with a nail and hammer while holding securly until you hear a ssss then put it outside for a minute. I always drill out the top, the bigger the hole, the faster it will be filled. But with LE's, you have to worry about confinement. I know I have made the holes slightly too large for use with Pryodex before, IIRC I used a 9/64" bit. It did seem to make a decent rocket though. Next, you'll need a large straw or something that will snugly fit over the top. The top is just a little over 1/4" wide. Then you'll need something to poke in the filler with. I usually use a bottle rocket stick. What ever is close and not metal. Then fill your straw or funnel and poke it on down. Repeat until filled how ever much you want it to be. It's been my experience that with most LE's you'll only need to fill it about half way or so to rupture the container. If you plan to ignite it with a fuse, I always like to put the fuse on a strip of duct tape, then put the tape around the cartridge. Then when I want to use it I will pull off the tape and fuse, put the fuse in, and put the tape around the fuse and cartridge to make it waterproof (if you are using waterproof fuse). This makes it pocket proof for me so the fuse won't be fucked up when I need it.


How to personalise

Antipersonnel - Get a length of duct tape, 8" will do, and cover all but the last 1 or 2" on each side with bb's. Then snugly wrap the bb laden tape around the COB making sure it is no more than 1 bb thick in any one spot (for even dispersion). However, you can apply more than one layer of the bb tape for more shrapnel. I have made only one or two of these and they seemed considerably louder. At a 7' distance, bb's were sunk approximately 1/2" into wood, which was somewhat soft. They were filled with Pyrodex, FFFG equivalent. HE would be much preferable for AP COB's. Needless to say, don't watch these go off, bb's fly fucking everywhere except from the ends of it.

Shotgun Compatable Antipersonnel - Someone could drill out the top of a cartridge big enough so it could take bb's. Then you could put in some bb's and glue and put it in a drill or something to keep it spinning long enough for the glue to dry the bb's on the inside of it. Then it could be filled with a HE.

Antivehicular - As NBK2000 mentioned here, (http://www.roguesci.org/theforum/showthread.php?s=&threadid=1732&perpage=50&pagenumber=2)someone might could put a SC into a COB. Needs researching to find the stand off distance (if any), iniation, ect.

Incendiary - If you have thermite, I would think you could use it as the filler. I haven't made any of these, but I would think it would burst the cartridge before it melted through it. If it does it would probably spread it around good, but I don't know if all the thermite would be ignited. Never used thermite so I don't know the characeteristics of it.

Smoke - You could fill with the KNO3/sucrose smoke mix or possibly KClO3 based smoke mixes if it is compatable with the cartridge (steel with the Lead seal on top I think). Be careful though, the thin metal of the cartridge will carry heat well, may start a fire.

Nonlethal Irritant - Might be of use to someone, someday. Read this (http://www.roguesci.org/theforum/showthread.php?s=&threadid=2649) to get an idea as to what to use as a filler.

Sticky COB - You could cut a 3" * 2 1/2 strip off of a sticky mouse trap. Then you could wrap it, sticky side out, around a COB with super glue on it. Just before use, you could pull off the protective paper and stick or throw it at the intended target, biological or not. Could be combined with the AP COB to make a sticky AP COB.


Use

With a HE COB, you could use it as a lock pick, small FAE initater, stun grenade (bit of shrapnel though :D), or just a generaly destructive device. Ie; someone wants to leave in their vehicle, and you don't want them to. Stick a sticky COB on their fuel tank. Some of these are compatable with NBK2000's idea of putting them in a 12 guage shotgun. The antivehicular COB would be interesting. Complicated though, like how to detonate at the correct distance. Also, you might get some shrapnel from one of them, since it is more or less directly ahead of you.


Hope someone else has some other ideas along these lines. Some consider COB's a little K3VVl™, they are a little, but they do seem to have possibilitys. Everyone do be careful if you make any of this stuff, esp if it goes out of a gun. Any comments welcome.

COB`s also come in 145 gram bottles too, the sort used in Soda Stream chargers and gas for beer barrels.

i`ll say no more :D

EDIT: and as an afterthough, i`ll not mention empty CO2 fire extinguishers either, that would be just OTT :)

I think using thermite as a filler wouldn't make a first choice incendiary weapon. Depending on the thermite you use, I think it will result only a partial ignition, and most of the mix will not burn. The mix burns quite slowly. You may use some BP or SP to allow the whole stuff to burn.

thermite will work in a 12gm CO2 case BUT as Arthis said and as i have found out myself, the problem comes with getting it to start the burn (it`s a right royal pain in the a$$).
i`ve got around this (tho still only a 50/50 percent hit) by making my own special fuses and yes thay are lit with an ordinary match or lighter.

it involves alot of time to make tho, as each layer needs drying time, and each layer needs to contain more and more thermite concentration.
my thermite is factory made and comes with it`s own seperate ignition powder (that`s my advantage).
as for the end result it`s a watse of time also, as the thermite uses most of it`s heat in melting the cob (quarter of it`s still usualy left over).
these are my findings.
thermite in a tin with a lid makes a better incendiary, less outside metal, and more area inside with which to put your ignitor. i`ve used these successfully many times to start pit BBQ`s on a beach lighting old (not always dry) drift wood :)

you mentioned also about using them for rockets, i`ve tried this many times, each time *BOOM*.
what`s your secret?

First off, I forgot to mention that you can use nitrous chargers as a COB (should I say NOB). They seem to be maybe a little louder, a little smaller, and a lot funner to empty :D. I think they might be louder because they are shorter, so the middle of it is a little stronger. I looked for the specifications of a N2O cartridge, but didn't find anything useful.

I am confused about thermite now, I have heard it will burn fast enough to rupture some stuff, and others say it is slow. I bet it's both, just depends on particle size of FexOx and Al, density, container, ect. But either way, I agree, there are better things for putting thermite in. It would be most useful if you needed a shotgun propelled incendiary, like to set fields or buildings ablaze from a good distance. Oh yea, one last thought, maybe it could be mixed with plaster of paris to be made solid. This might help it burn and be easier to ignite if a first fire mix was moulded into the tip of it.

Ahh, plus-sized COB's. You COULD use a 145 gram CO2 bottle, OR you could use an 11.3 Kg CO2 tank, for dispensing pop :D. Here (http://www.luxfercylinders.com/support/markings/) and here (http://www.luxfercylinders.com/products/beverage/specifications/us_imperial.shtml) are some of the specs (product #C020). And of course, I got mine from dumpster diving. Someone could easily steal one though, they are sitting behind a stores and concession stands all the time. I was planning this for the 4th of July, but I am too broke and didn't have enough time to fix it. If you look at it (http://www.luxfercylinders.com/products/beverage/) (the second tallest one), it kinda looks like a bomb thats dropped from an aircraft. Anyway, just thought I would share this. Someday when I get something to fill it with, I will be sure and get it on video for everyone. BTW, AN isn't compatable with Aluminium is it? Suppose I could Plasti-Dip the whole inside though.

Yt2095, I figured it out on accident and much to my annoyance, that when using Pyrodex and when the cartridge opened to 9/64", it will not rupture it. I made three or four of these about 2 years ago and they just went sssSSSHHH. I am sure you can use all kinda of LE's. But if it burns too fast for the gas to be let out of the hole, boom. Faster the propellant, the bigger the hole need be, so stuff like flash and high mesh high quality BP will probably not work. I have no more bits or I would try some rockets.

Well... I have made both smoke grenade type impact co2 mortars, and after reading this I decided to make a co2 flash bang which hasn't yet been set off. I'll try to take some pics of another smoke mortar before and after initiation sometime in the next couple days, but I have a couple pics of the flash bang for anyone who wants to look. Flash bangs are kinda old news though. No one really cares about em anymore I don't think.

Pics of the flash bang can be found here. (http://i-was-bored.8m.com/CO2)

Cricket, the burn rate of thermite can be control if you want. As you have said the particle size is a factor but you can also use different constituents. For example using magnesium rather than aluminium will speed up the burn although magnesium is harder to get hold off.

the factory thermite i use is zinc/copper for bronze welds the particles are the size of course beach sand (it`s very bright and exothermic though!)

some other thermites i`ve learned are actualy borderline explosive, copper oxide/Alu and also lead oxide mixes are quite violent and would most certainly rupture your vessel. i started a thread on here titled "exploding micro balls" the other people on here were quite helpfull as to what they may be, the general concensus is that it`s a lead based thermite and that looking up "Dragon eggs" would be worthwhile.

thermite as a term is bit lke saying "flash" mix. there are many sorts (i`ve learned a few myself on here as well).

so sure, your 100% right, some will go boom and others will just melt, mine just melts (and was a total b!tch to light). particle size will slow or speed your reaction for certain, but the greater the size the harder to light. i`ve never seen Fe/Al thermite in real time, only on TV, it seemed more ot less the same burn rate and brightness of my bronze thermite, though i expect the temp would be somewhat higher.
as Streety said, the actual compounds used to make it would have a greater impact on burn rate/temp than particle size alone (maybe a good combo could be employed to get the EXACT effect your after?)

all the best :)

If you do use a lead oxide based thermite though I wouldn't want to be downwind of it.;)

I've also heard of teflon being used in thermites although I can't remember what that was mixed with. Anyway the teflon is liberated and produces a poisonous gas cloud. Again be upwind.

I love to learn new shit. I have heard of there being a teflon containing thermite too, don't know the specs or the ratios though. I didn't know you could use lead compounds in thermite. I bet there are plenty more too. Very interesting.

Ps, I would also like to add, COB's are great for exploding slightly underwater, 2 feet or so. At my friends all the fish within a 25' radius of the COB jump up out of the water and swim around at the top for while. Absolutely the funniesy thing I have ever seen. I hope to get a throwing net soon.

The fish will swim to the surface because the shock of the blast liberates all the oxygen in the water and the fish have to surface to be able to breathe, they can then be picked off with a rifle/ air rifle/crossbow/longbow if you want.

I will also add that not only do COBs come in 12gram and 145 gram, there are also ones in between these sizes for air rifles and lifejacket inflation. There are also VERY large ones used in sodastream machines (I'm unsure of the size, I would say 500 - 600g) and a friend of mine has an empty one. They have a valve on the top that has to be unsrewed with a big wrench before you can use them. My friend and I have thought several times about having a dream where we fill it with APAN but we have always decided against it (it would be extremely violent, loud, and dangerous to the surrounding area and we don't have a suitable place to set it off).

Also, the COB fillings that I have had good results with (I use HEs in my COBs as I have never been able to make good LEs):

Straight AP or HMTD
25% AP / 75% AN
25% AP / 75% KNO3

I think the fish would be stunned, and therefore float to the top, rather than being deprived of oxygen. Think grenade fishing :)

A single COB stunning fish 25' away? It could be a combination of the two. I read that thing about the oxygen being liberated from the water in the SAS survival guide section on blast fishing.

Edit: Has anyone tried that explosive fishook thing with a COB that is on the end of a fishing line and has a pull string ignitor in it with a fishook on the end of the pull string? I have always wanted to try that but never got around to it.

They only come out of the water within the second of the explosion, all at the same time pretty much. To me, it sounds exactly like when you go to get some ravioli out of the pan and stir it around a little. That's one reason why it's so damn funny. Some of them that I assume were too close to the blast stay near the top and swim around for a minute like if they were out of air, but you could tell they were messed up in the head. I've seen fish out of air and fish knocked senseless, and they do act simular, but the senseless one seems less balanced. Anyway, I will hopefully try this with a fishing net soon and post the results if anyone is interested. Also, I could get this on VHS and send it to someone if they were able to upload it somewhere.

Oh yea, xyz, read post 5 paragraph 3 in this thread. I think we have the same ones. Look at the pics. But HMTD and AN aren't compatable with aluminium are they? I am thinking of throwing mine into a pond and making it rain :) . Hopefully, there would be no water left, just a bigger hole. Good times.

No cricket, I don't think I have the same one. The one that I have is taller and thinner with a rounded bottom and a smaller valve. Mine is made out of steel, not aluminium.

HMTD is not compatible with aluminium (and most metals for that matter) but AN should be fine if it is used the same day it is filled.

The shockwave ruptures the fishs' swim-bladder, which they use to maintain boyancy. An equal number probably sink to the bottom. I guess it's a lot like submarines attacked with depth charges.