Water charges

[nbk2000]

I saw the 'Alford Strip' on this segment of Future Weapons http://www.youtube.com/watch?v=Va9lOszglrs

A simple plastic channel filled with water, with a recessed grove for a length of DET-CORD.

The water provides a countermass, or tamping effect, to the explosive force, directing it into the target more effectively than simply taping the DET-CORD to it.

To me, it looks like a pre-made piece of plastic trim, like something you'd find on the edges of cabinets, so a good search of suppliers of such thing would likely reveal an OTC supplier.

Anyways, the exact material or shape is likely irrelevant, as long as it disintegrates safely and has enough mass to direct the force of the explosion into the target.

Previously I've mentioned a castable disintegrating tamper patent. Water is safer, and quenches the explosives hot gases.

Also, if the tamper was made from rubber tubing or such, it could be kept unfilled and highly compacted and, more importantly, unsuspicious.

By having a tube with the tube, you could use a liquid explosive too, making the whole thing easily transportable and its true purpose undetectable prior to actual setup. :)

Ever seen a Bunt Cake Mold?

http://www.sugarcraft.com/catalog/pans/2105-4013.jpg

To me, this just screams out "Door Hole Puncher", hence my creation...the 'Bunt' charge. :D

A circle of very thin aluminum sheet (soda-can like) has a ring of explosive, either plastic or liquid in a tubular ring, set on it and affixed into place with glue, and either a rubber coating or plastic film covering it.

The bunt mold is centered over it, and firmly sealed to the circular plate.

A small tap hole with plug has already been made in the bunt mold for the water to be added, and leads for the detonator as well.

The center hole is where your detonator, timer, whatever, goes.

A peel-off adhesive sheet on the aluminum circle is used to attach it to the target door and BOOM! You've now got a hole big enough to reach your arm in through to open the door, toss in grenades, or fire your weapon.

They also make the molds out of silicone rubber, which would be fragment-free, but save money and buy steel.

The second half the the FW episode has a larger version, very similiar to the well-known Hydra-Cut Frame.

http://www.youtube.com/watch?v=zVt9iutUgAY

Same principle as the Alford Strip and the Bunt charge, only larger.

[knowledgehungry]

I was talking to my buddy home on leave from Iraq a few months ago and he told me that a favorite IED, for blowing down doors and the like was a blasting cap and an IV bag. I am not sure if he meant that the insurgents used them or whether the troops use them. Since he is an MP I tend to lean towards the idea that our guys use them when storming a house.

Unfortunately he is back over there so I have no way to ask him about it.

[nbk2000]

That's another form of breaching charge.

Three lengths of military DET-CORD are looped in between two IV bags, and propped against the target door.

The bag furthest outside acts as the countermass, and the inner bag acts as a ram. The door typically bends inwards enough to clear the lock bolts, if not outright shatter the door (if wood).

[akinrog]

The old guy in the video is the same guy I watched in a documentary of National Geographic channel about dam busters, a special air raid unit of World War 2, aiming at demolishing various dams in Germany.

In that documentary the old guy was describing how water behind the charge helps to demolish dam during attach by attaching an IV bag behind a detcord and repeating the same experiment without an IV bag.

[Guerilla]

A 0.5L waterbottle with a lenght of mil detcord wrapped around can also be used for more directed blasts on softer targets. A quick improvised way to take apart (or trigger) electrical circuits etc. but probably harmless against any sturdier locks, enough to penetrate an average car's rooftop and come out through the bottom though.

[nbk2000]

Here's a hi-res (1MB) photo showing the construction of a Mineral Water Bottle (MWB) charge:

'http://www.shaw.af.mil/shared/media/photodb/photos/060601-F-6699G-010.jpg'

Copy/paste above link into a download utility to save it.

A 3-strand loop of DET-CORD is taped on one side of a small water bottle (like evian), which acts like a shaped charge, directing a high-speed jet of water into the target.

Also, a patent for water-disruptors: US6269725

A photo (1.5MB) of a charge made according to the patent:
https://navcms.news.navy.mil/management/photodb/photos/060712-N-8148A-061.jpg

Source of details (Page 13):
https://aais.ria.army.mil/AAIS/Award_web_03/DAAE2003D00460026/PDExplosive%20Ordnance%20Disposal%2028Nov06.pdf


Disruptor, Fluid. The fluid disruptor shall be a Hydra-Jet manufactured by Cherry Manufacturing Inc., Albuquerque, NM. The disruptor shall be an explosive device disablement tool that mass focuses a fluid into a linear knife blade-like projectile through the use of a chevron shaped explosive charge that is centrally fired at the apex of the chevron. The disruptor shall also be capable of having a metal disk conformably mounted to the disruptor’s exterior and radially aligned with the direction of fire of the fluid projectile. The disruptor shall be able to be remotely actuated, and shall be able to be hor robotically emplaced. The disruptor shall be able to be used singly or in multiples, or in combination with other disrupters. The disruptor shall be capable of penetrating hardened targets, multiple barriers, and possess standoff capabilities greater than or equal to 5 feet. One case of 16 disruptors shall be furnished in each size: Small (32 oz), Medium (64 oz) and Large (128 oz). The only known product that will meet the requirement is the Hydra-Jet manufactured by Cherry Manufacturing Inc., Albuquerque, NM.


A BP-powered water-jet door rammer:
http://www.eodpartner.com/eng/02products/01eod/0205400_handheld_disruptor/0205400eng.pdf

Regarding the water-filled tupperware bowl:

Someone mentioned that filling a Tupperware bowl with water and wrapping the bowl with detonating cord would make an improvised shape charge. We promptly put one together and propped it against the outside wall using a two by four. The device was detonated and sure enough, it knocked a four foot diameter hole through the cinder block wall.

Though I think this likely an exaggeration.

[knowledgehungry]

I was thinkin about using gelatin as opposed to just plain water in the "bunt cake charge" or other improvised versions. This would eliminate the difficulty of making sure the water didn't leak out.

The hardest part of improvising these things would be in making a water proof "face" for the container holding the water. If you used gelatin you wouldn't have to worry about that. You could fill a large, deep cake pan with the gelatin , press the detcord/plastic in the desired pattern into the pan, then ductape it to the target. I think it would be more simple than having to find a way to contain the water.

The ony question is would the difference in physical properties of gelatin and water somehow interfere. I believe that they would not due to the fact that the water is merely there to tamp the explosive, and gelatin is almost as dense as water.

Akinrog: I saw that show a long time ago, thanks for reminding me of it it was very interesting.

[FUTI]

I don't know how you call this guys...but partially acid hydrolysed starch when cooled form jelly like mass. Maybe that can make your countermass for that charge like gelatin or water?

[Bert]

NBK, the high res photo link is broken-

[nbk2000]

I think that plain water is used both for the simplicity of loading, as well as it's ability to absorb the heat of the explosion by conversion into steam.

Gelatin probably isn't as effective at the last, but for a DIY charge, it would make it much less likely to leak out.

Other materials would be water-absorbing soil polymers. Blended to a fine powder and mixed with several hundred times their weight of water, they form a very solid gel, with no decay like organic-based gelatin would incur over a long period of unrefrigerated storage.

[nbk2000]

I forgot to mention that the photo at 'http://www.shaw.af.mil' can't be opened in browsers, it has to be downloaded using a download utility.

[Bacon46]

NBK

How about using a small inner tube, like one from a hand truck, to keep the water in your “Bunt Charge”?

I am more into pyrotechnics, but based on what I have read so far. it seems to me that it would work.

I attached a line drawing and cross section.

http://img403.imageshack.us/my.php?image=buntcharge2wc4.jpg

http://img167.imageshack.us/img167/9971/buntchargesectionsi1.th.jpg (http://img167.imageshack.us/my.php?image=buntchargesectionsi1.jpg)

[nbk2000]

An inner tube would also work.

But, from your graphic, it'd be unnecessary, since the bunt mold is being clamped between two boards, which would make it watertight anyways, right? ;)

[Bacon46]

I really didn’t think the graphics where necessary, but I think I remember something in the rules about including them whenever possible. I draw for a living, and had time, so it was possible!;)

As far as the mold being watertight without the inner tube; if the material used to fabricate the “Plates” is waterproof and the joints are sealed with silicone during assembly I suppose it would hold water. If wood is the material used, I wouldn’t count on it to hold for very long.

In an experiment or demonstration, there is obviously no need to fill it until right before you detonate it. In a hypothetical combat situation, where one actually needed to use the devise to blow a door, the inner tube would give you an unlimited amount of time between filling and detonation.

Wouldn’t you hate to be the guy in a combat situation looking for a Bunt Cake mold and an inner tube? You better have a plan “B”.

[festergrump]

I kind of see where Bacon could be on to something with the innertube idea... If it were filled even to 7/8 of the tubes capacity (without expanding) and the wooden 'plate(s)' were left off, it could be as portable as a satchel charge if everything was stickied in place somehow, and you'd have less time testing your cake-tin to sheeting bond to be sure it holds water (I'd trust a machinemade innertube over my aluminum on aluminum bonding capabilities anyday, especially if they were meant to hold water).

Maybe hotglue or use a tube of subfloor caulk to keep the innertube into the bunt-cake tin and doubleside tape the LSC in place? Voila! No time wasted in filling with water at all. Just sticky, magnet, or screw to the door (which ever is best suitable), and say GO from a safe and remote location.

If weight is of an issue but time is not... fill on site with available water, instead, and save yourself 8-16 lbs of dead weight while hoofing it to the breach zone, as the original post.

I can see a small team carrying many of these on a mission.

[nbk2000]

Another modification would be the addition of a chemical agent to the charge, so that the agent is directed into the target zone during the explosion.

By placing the agent between the target and the explosive, that will direct it in through the hole, into the room beyond.

Since agents take time to take effect, this would be best used in a multiple hole operation, where you have several entry points planned, the primary being ungassed, with the secondaries (entrance/exits), not being intended for immediate use, getting the treatment.

Then, if you need another entry point, it's already been cleared by the agent. Or, if you need a quick exit, you don't have to worry about the room being occupied.

The same could be done with the tamping water, loading it with a volatile agent, so that the area around your entry point remains clear of anyone laying in ambush for you as you are exiting.

[megalomania]

What about using some inert, but incapacitating, agent like chloroform or carbon tetrachloride instead of water? Now you have filled the target area with as much toxic vapor as possible. Even something like different bags of hydrochloric acid and ammonium hydroxide would make an instant smokescreen. While I am on it, using concentrated sulfuric acid or saturated sodium hydroxide also sounds like it could ruin somebody's day.

[nbk2000]

Pictures of commercial breeching frames and the resulting damage:

http://www.forcedentrytacticaltraining.com/forced-entry-tools/more-entry-tools.php

An article from a piggy magazine describing various breaching techniques (also attached):

http://www.hendonpub.com/article-print.asp?ID=890

It was deleted from their website, but the google archive still had a link to the print version, which was still on their site. :p

[FUTI]

What about using some inert, but incapacitating, agent like chloroform or carbon tetrachloride instead of water? Now you have filled the target area with as much toxic vapor as possible. Even something like different bags of hydrochloric acid and ammonium hydroxide would make an instant smokescreen. While I am on it, using concentrated sulfuric acid or saturated sodium hydroxide also sounds like it could ruin somebody's day.

The solvent use idea goes little in CW area but is OK and cheap. But if I may propose one 2-in-1 product based on what you proposed Mega. Ammonium hydroxide and concentrated sulfuric solution also looks very good. IIRC heat of reaction of those two is high enough to boils of the water (not to mention the "slight" energy input from the blast) so you end up with aerosolic salt which also form the smoke. Blast them, boil them, smoke them...

NBK when you mentioned soil polymers did you think something like those acrylate binders they made for soil remediation or some zeolite solution (like some kind of clay)?

[Chris The Great]

There really is nothing new about this concept at all except that the tamping has been made more portable.

Why not use an inflatable pool toy filled with water, and tape some detcord (or even a narrow strip of plastic explosive if you're doing everything yourself) on one side. It's ready to go and it will only cost $3 for the pool toy and $5 for the roll of tape. The only problem I can see if that if there is a lot of water being used, it might be hard to tape to a door since it will be very heavy.

Since pool toys might be a little too large, one could always tape them down to be smaller before filling with water.

[markgollum]

Using sulfuric acid or chloroform as the tamper is a great idea, especially since their densities are 1.836 g/cc and 1.48 g/cc respectively (@ 20deg C) that translates into 1.836 and 1.48 times the tamping effectiveness per unit volume.
But if you want maximum tamping effectiveness without the cost and toxic/irritating effects
then I would go with a saturated solution of calcium chloride, 74.5g/100mL @ 20 degC and the density of the 40% solution is 1.3982 g/cc @ 20 deg C.
There are solutions made up of zinc, calcium, magnesium, and mercury bromides/iodides that have densities greater than 3g/cc but they don’t come as cheap.
I think everyone can imagine the $$$ remediation problems mercury would cause.:p

[tiac03]

While we are on the topic of water tamping... Would it affect shaped charges and EFPs, If so would it be enough to make them worth while?

(Ability to use less explosive, or to increase penetrating power of them?)

[nbk2000]

Confinement of any charge improves efficiency and reduces the weight of explosive needed to perform the same work.

I like the idea of using CaCl solution, as it's denser than plain water/non-toxic/cheap/non-freezing.

Acids?! :eek: Remember, you'll have to go through the stuff on your way in/out, probably without a haz-mat suit, so you want to use something corrosive?

A water-soluble irritant would be good to add. A lot of the water will be vaporized into steam or fog by the blast, though most of it will be dispersed on the charge-side of the wall.

Though, if one had access to DET-CORD, delayed detonators, or a blasting box, they could set up another directional water-charge like the one shown in the navy.mil photo I linked to, replacing the water inside the charge apex with an agent, which would be directed through the hole in the wall that you had just blasted. :)

[akinrog]

Acids?! :eek: Remember, you'll have to go through the stuff on your way in/out, probably without a haz-mat suit, so you want to use something corrosive?


I believe the original posters who suggest chemicals for smoke / corrosion etc. effects have misunderstood the concept. The water tamper is not before the charge but behind the charge.

So using a chemical which is irritant /corrosive or smoking should be a bad idea since you are the one who shall be sprayed by these chemicals while the people at the other side of the wall shall be relatively protected from them. Regards.

[Kaydon]

SHAW AFB, is nearby. Very.. nearby.

Paraphin(sp?) wax? Would that work, or just explode into bits? Perhaps a mixture?

[slarter]

I believe the original posters who suggest chemicals for smoke / corrosion etc. effects have misunderstood the concept. The water tamper is not before the charge but behind the charge.

So using a chemical which is irritant /corrosive or smoking should be a bad idea since you are the one who shall be sprayed by these chemicals while the people at the other side of the wall shall be relatively protected from them. Regards.

Actually, the water surrounds the explosives. These charges operate on the principal that you cannot compress a liquid. The explosive forces the water against the target either displacing it or breaching it altogether.

I've used the "Boot Bangers" from Alford and the "Mineral Water Bottle" and "Hydro-Cut" charges made by Chris Cherry in Iraq and both work very well. You can make your own and for a lot less money.

It is amazing how little explosive it takes to breach a door or pop open a car. 20g is sufficient to open just about any Class A steel firedoor if used properly.

As for using paraffin, absolutely not! The detonation will cause it to ignite.

While going through an "Explosive Breaching" training program years ago (before the advent of non-flammable breachers paste) we used GAA (Grease, Automotive and Artillery) as an adhesive to attach the breaching charge to the target. GAA would stick to wet teflon and just about anything else. One of the other students decided that if three small dollops of grease was good to hold the charge to the target, then three pounds or so would be better.

I was the shieldman holding the ballistic shield so we could detonate the charge from less than 8 feet away (the NEW was less than 75g) and when the charge detonated, it vaporized and ignited the grease, creating a fireball about 25' in diameter. :eek:

The instructor was the fifth man in the stack and he was inside the fireball. Good thing that we were required to wear Nomex flightsuits and hood with helmets and goggles. I just wish that someone had had a camera that day.

[nbk2000]

I've used the "Boot Bangers" from Alford and the "Mineral Water Bottle" and "Hydro-Cut" charges made by Chris Cherry in Iraq and both work very well. You can make your own and for a lot less money.


Any details on how to make our own?

A short news segment where a company that trains piggies in explosive breaching demonstrates it for the reporters.

http://www.breacher.com/videos/Breacher.WMV

You can clearly see the construction of a Water-Impulse charge using DET-CORD sandwiched between two water bags.

[Rbick]

Yes, water impulse charges are very easy to make and there are several ways to do it. We were taught in an improvised explosives class. I will scan and put my notes up later in links and literature.

My favorite way was to take 2 saline solution IV bags (500 ml) and place some C2 sheet explosive in between them. I used duct tape to keep them held together. I'm unsure of the amount of C2, but it fit squarley between the bags, so about 5 x 4 in squares, and was folded about 4 times. I primed it with a pen flare gun(this was an improvised explosives class :D) , some shock tube, a blasting cap and about 6 in. of det cord. We were only using some heavy interior doors that day, but damn, it was awesome. To better explain the pen flare gun, it is the size of a normal writing pen, but is used to launch small signal flares. It has a striking pin that fires the flare, but in this case strikes the shock tube primer. The blasting cap had a 5 second delay after being initiated by the shock tube, allowing you to seek cover around the corner and get your weapon ready.

Considering the normal person will never get shock tube or C2 sheet explosive, or even IV bags for that matter, there are a lot of alternatives. Ziplock bags filled with water would work, and a fuse or electrical initiation would work for firing the cap, obviously. Any charge could be used, as long as it is fit snuggly in between the bags of water. Preferably, you would obviously want something very brisant, like RDX or PETN. When placing the charge, we put ours next to the locking mechanism, about 3 in. off to the side towards the middle of the door. This ensures the locking mechanism is destroyed. Make sure the bag is in full contact with the door and there is as little space as possible. If you wanted, you could just put strips of det cord between the bags, but adding a nice charge makes sure you punch through.

Another method is to take a bottle of water and drill a hole in the top, or just take the cap off. You then suspend a charge in the center of the bottle, so it is completley submerged. Then, attach the bottle to a stick, and lean it against the door. When it is leaned against the door, ensure the charge stays in the middle of the liquid. If you can, use adhesive to attach the bottle to the door, as a leaning stick could turn into a big piece of shrapnel headed your way :eek:

If I think of more details on this type of charge, I'll be sure to update, 'cause I'm missing something. I just don't have my notes with me at the moment.

[Zait]

A short news segment where a company that trains piggies in explosive breaching demonstrates it for the reporters.

You can clearly see the construction of a Water-Impulse charge using DET-CORD sandwiched between two water bags.

That is Rus Hart from R.E.S.T. They run a pretty good school.

It's more than just det-cord. If you go back and look closely at the video they are enhancing the charge with some deta-sheet (looks to be C2) and the det-cord is laid over the top of it.

[Gammaray1981]

Who in the world gives ImpExp classes post 9/11? Surely the bureauprats would shut them down?

[nbk2000]

We're still here and have been for 6 years, post 9/11. :)

As long as FedGov has to give at least lip service to the 1st amendment, we have nothing to fear as long as we discuss such matters in a public matter.

Once you start privately discussing such matters, it becomes conspiracy.

Anyways, I'm uploading to the FTP uploads folder, a 22MB file containing several PDF's I've compiled about the construction and use of various breaching charges, along with 11 videos showing them in use and their effects.

(And, yes, I realize that one of the videos is a duplicate, but only after I had uploaded it)

[Gammaray1981]

Ah. I hadn't though of it in quite that way. I was thinking of the probability of a vanful of pork smashing down the door and arresting everyone inside on the basis of "training terrorists". Here, it might as well be roleplay, for all that can be proven.

[nbk2000]

Water bottle disrupter charges table:

Nominal capacity, dimensions, water filling, charge weight

.25L, 148mmx60mm, 174ml water, 57g HE
.50L, 198mmx85mm, 650ml water, 57g HE
1.0L, 247mmx100mm, 1130ml water, 194g HE

[Gammaray1981]

How does #2 work? Nominal capacity: .50L = 500ml. Water filling (excluding all else) 650ml?

[nbk2000]

Nominal = Approximate or rounded off.

What's easier to say? 'Half liter' or '650'th of a liter'? :rolleyes:

[Jacks Complete]

Gammaray1981, the reason for the higher amounts of water is that you don't want any airgaps in it, unlike when you buy a beer and it has that air gap at the top to stop the bottle exploding from pressure shocks. Think about it.

[nbk2000]

I uploaded some pages from a soldiers notebook on improvised demolition charges:

/FTP/UPLOAD/NBK2000/Explosive Breaching/Notes from MOUT Demolitions Class.pdf

Most of it is, to be expected, similiar to what's described in the militaries TM and FM on such things, but personal commentary is always interesting. :)

[Tinton]

A generalized ratio of water/explosives would be nice for this.

Anyways, might a garden hose, or other similar tubing be used?
Although it may be difficult to completely encase the explosive with the tamping water, I'm sure someone could pull it off.

A hose/tube filled with water, and an explosive. Just lay it on your wall. Tape it every foot or so. And BOOM. You could practically write stuff in a wall/door.
This would give you flexibility, without having to use set shapes and premade containers. It would also make attaching the device much easier than a "sticky" charge. Additionally, it would be extremely easy to carry, seeing as it can be wound.

[Rbick]

Check out this video (http://www.youtube.com/watch?v=eFh1FWluixg&mode=related&search=)from Future Weapons. About 1 1/2 minutes into it, he brings out what is called an "Alfred Strip". I have found window seals that look very similary to this and could be made to hold water. I'm sure you can make something similar to it using different materials as well. Its a good video though, lots of good information on water charges. It may have been listed earlier in this thread, but its good to bring it back up. That old guy in the video rocks, I plan to be like him when I'm 80 :D

Trinton- I'm not sure what you mean by using a hose. Woud you fill the hose with water, explosive, or both? I assume it could probably be made to work, sounds like a fun experiment to try out :cool: If you filled a hose with explosive, that would be some thick det cord!

[Tinton]

I meant using a hose, as in using it as the tamper. Fill it with water, and tape detcord to it. You could also attempt to get the explosive inside the hose. So you have one compact, prepackaged water charge.

Actually, now that I have given it more consideration, you could use the garden hose as the explosive.
What I mean, is that you could fill the garden hose with explosives; then put that hose inside another piece of tubing, with a much larger diameter. (2in?)
Fill the larger tubing with the water, make sure the hose of explosives stays in contact with one of the sides of the larger hose.
Just make sure you mark which side of the large hose the explosives are in contact with, so you know which side to place towards the wall. ;)

[Zait]

About 1 1/2 minutes into it, he brings out what is called an "Alfred Strip". That old guy in the video rocks, I plan to be like him when I'm 80 :D


"Alford strip" as in Dr. Sidney Alford. A very nice gentlemen when you get to know him.

Unless the "window seals" you are looking at are rigid and can hold water you won't get anywhere near the results you are looking for. Especially if you aren't using det-cord.

[Rbick]

Eh, Alford, whatever :p. Yeah on a second look, you're right about those seals, they don't look too promising. But what could one use to get something similar? I'm on a quest to find it, 'cause those cutting charges are sweet.

[Zait]

But what could one use to get something similar? I'm on a quest to find it, 'cause those cutting charges are sweet.

The container is not always as important as the explosives used. You need det-cord or sheet explosive to effectively make a breaching charge.

[nbk2000]

This months SWAT magazine has an article about Brazilian police, and has a picture of a wall breaching charge made from dynagel cartridges and det-cord, called a 'spider' charge, and will blow a manhole through a 6" solid concrete wall.

[Rbick]

I'll have to disagree with you there. You don't NEED sheet explosive or det cord to make a breaching charge. It also depends on what you're breaching. Flex linear charges are C-4 packed behind a copper strip. No det cord or sheet explosive involved. M112 blocks of C-4 are used to breach walls (the blocks can be replaced by many other explosives), and water charges can be made with almost any type of explosive.

For flex linear charges, the container is what makes it so effective. It wouldn't do its job without the copper strip at 60 degrees. This is obviously the case with all shaped charges, where the container does make the difference.

So actually, it is a combination of both. You need both an effective container and and effective explosive to make it work properly, depending on your target. As for the Alford strip, I think that its container plays a vital role in having it work as well as it does. Yes, sheet explosive and det cord are nice to have, but certainly arn't a requirement of making effective breaching charges. NBK mentioned adding some notes to the FTP on this matter a few posts up. It seems pretty interesting and may be worth checking out...

[Zait]

I'll have to disagree with you there. You don't NEED sheet explosive or det cord to make a breaching charge. It also depends on what you're breaching. Flex linear charges are C-4 packed behind a copper strip. No det cord or sheet explosive involved. M112 blocks of C-4 are used to breach walls (the blocks can be replaced by many other explosives), and water charges can be made with almost any type of explosive.

For flex linear charges, the container is what makes it so effective. It wouldn't do its job without the copper strip at 60 degrees. This is obviously the case with all shaped charges, where the container does make the difference.

I must not have come across correct in my last post.

If you are trying to use some type of frame like plastic tubing, window seals or anything else like that you will not get the desired result without using det-cord or sheet explosive.

If you have flex linear (copper or lead or even ECT for that matter) then you don't need a plastic frame (Alford Strip) to use with your explosives. You can use M112 blocks but that is kind of like killing ants with a sledge hammer. It works but the extra damage usually isn't worth the effort. BTW Flex linear does not use C4 as the main charge. Flex linear usually uses either RDX or HMX depending on the manufacturer and the application for the charge.

As for the Alford strip, I think that its container plays a vital role in having it work as well as it does. Yes, sheet explosive and det cord are nice to have, but certainly arn't a requirement of making effective breaching charges.

The container plays a large role for it's ability to remain rigid and to contain the water. You can accomplish the same thing with a zip-loc bag but because of its flexibility you need to use more water and explosives to accomplish the same task. 99% of breaching charges used are constructed using either sheet or det-cord. Short of a heavy breaching operation (Combat Engineer style) M112 blocks, boosters, and the like are not used. Conversely, no one is using AN, Flash powder, black or smokeless powder for breaching as it is not suitable for the application.

Were you to try anything less than det-cord in the Alford strip you wouldn't get the desired effect. That's why Sidney designed it the way he did.

While breaching is a "science" it is also an art. It takes quite a bit of explosives knowledge to mix a container and the correct explosives to make an effective breaching charge.

[Rbick]

Thank you for the clarification. I understand that you don't need plastic tubing for flex linear charges, I have handled many of them. But it is important to use a properly shaped metal strip with a properly shaped and weighed charge behind it with what is usually a foam casing around it, which I was describing as the container.

I also understand that M112 is too much for a door, but not for a thick wall. I've seen these in action and they do form a perfectly sized whole in concrete walls to move through, unless of course the wall sucks and collapses, which has also happen. This isn't always bad, since the obstacle has been completely removed. :D

My idea for the window seal was to get something close to what was shown in the video. Of course it wouldn't perform as well, but hopefully get close. On a second look, it doesn't appear that it would do much of anything. Ziplock bags can be used, as IV bags are often used for improvised water impulse charges, but those do not give you the clean cut of the Alford Strip, which is what I'm looking for. Bags of water work great for minimizing frag, but push, rather than cut your target.

Also...
BTW Flex linear does not use C4 as the main charge. Flex linear usually uses either RDX or HMX depending on the manufacturer and the application for the charge.

C-4 is not the name of a single explosive, it is a composition (hence the name, Composition 4) made up of about 91% RDX and 9% plasticizer and binder by weight(depending on the manufacturer), which is what is used in flex linear charges. The plasticizer is usually dioctyl sebacate or dioctyl adipate, and the binder usually used is polyisobutylene. It would be much more difficult to place pure RDX in a shaped charge.

I agree with you that people do not generally use AN, flash, ect. for breaches, as they are not desireable. I was just pointing out that in a situation where you need to improvise, it is possible to use these. And you're right about it being a science and an art, but all can be gained through research and experimentation.

[Zait]

But it is important to use a properly shaped metal strip with a properly shaped and weighed charge behind it with what is usually a foam casing around it, which I was describing as the container.

Actually, you don't need a metal strip. Metal is good, but not required as many other products work as well or sometimes even better. The liner only enhances the depth of the cut. A simple cutting charge can be made by cutting a "V" impression into the charge or forming two strips of explosives into a "V" with a little backing for support. This was initially demonstrated by Munroe using a block of guncotton. It is further demonstrated by the brass plaque sitting on my desk that was nothing more than C2 detasheet and a reverse engraved plastic plate.


C-4 is not the name of a single explosive, it is a composition (hence the name, Composition 4) made up of about 91% RDX and 9% plasticizer and binder by weight(depending on the manufacturer), which is what is used in flex linear charges. The plasticizer is usually dioctyl sebacate or dioctyl adipate, and the binder usually used is polyisobutylene. It would be much more difficult to place pure RDX in a shaped charge.

You forgot to add in the DMDNB (2,3-dimethyl-2,3-dinitrobutane) that is required to be added to the mixture. Having spent the past 20 yrs using various explosives and demolition materials I'm quite familiar C4 along with many of the other explosives commonly (and not so commonly used). You stated:

Flex linear charges are C-4 packed behind a copper strip.

"Flex linear" is a type of charge used by the military, law enforcement and some civilian demolition specialists for specialized cutting (FLSC or Flex-Linear Shaped Charge. It somes in various grains per foot ratings (15gr/ft to around 5000gr/ft) and is sheathed in either copper or lead. The military still uses lead while the rest use copper. These commercially manufactured flex linear charges are not "C-4 packed behind a copper strip". They are a strip of RDX or HMX totally sheathed in lead or copper (with the exception of the end being exposed). The military also uses the foam encased "MK 142 series ECT" or Explosive Cutting Tape for some very specialized purposes most of which are underwater. Bonus points for those that correctly state why foam (with no metal content) is better underwater.

[nbk2000]

Reasons for foam:

A) Non-corrosive
B) Decouples the shock from the water, reducing the distance the divers need to be for safety
C) Positively-buoyant (?)

The FLSC I've seen was PU foam-body, PBX-cored, and polymer-bound copper powder liner.

I think the Alford strip is an optimized container for using Det-Cord, but the same effect would be afforded by using water-filled plastic bags, just messier.

[Zait]

Reasons for foam:

A) Non-corrosive
B) Decouples the shock from the water, reducing the distance the divers need to be for safety
C) Positively-buoyant (?)

Close but no. I'll go a bit further in hinting that the MK 142 series contains no metal liner. I'll try to get a picture of some up today since it will help in fleshing out the answers.


I think the Alford strip is an optimized container for using Det-Cord, but the same effect would be afforded by using water-filled plastic bags, just messier.

Pretty much dead on there.The problem with the water filled bag is that it takes more water since it is less rigid. The strip is easier to manipulate and place requiring less time on target and less material to emplace (tape).

[Rbick]

Zait-
Thanks for pointing out the use of DMDNB, forgot about that. To let you know, I am very familiar with the "Munroe Effect". It was discovered in 1888 when Munroe was testing explosives (nitrocellulose) on metal plates and noticed the manufacturers name imprinted on the plates after detonation. Yes the addition of the strip does greatly increase the cut, and thats all I have ever used.

The flex linear charges I have used were not sheathed in Copper or Lead. They were C-4 behind a copper strip. You could actually take the C-4 out of the foam and mold it or use it for other applications. In my military unit, our flex linear charges used Copper, not Lead and we used as large as 5200 grain strips. I actually wasn't even aware they had flex linears with pure RDX or HMX. Seems we've worked with different stuff :p. We used ECT for breaching doors and gates, never under water though. Thats probably 'cause the Army hates water, we prefer nice dry land. We also made something called a "G" charge with 5200 grain ECT. It was 12 lbs stuck onto a plywood board in the shape of a G. It was used to take down the side of a house with the bad guys inside. They were kind of suprised :D

[nbk2000]

What, no fragmentation? So SEAL's can carry it, slap it onto a ship hull just above the water line, duck under the ship, and pop up into the hole made by the FLSC?

[Zait]

What, no fragmentation?

No metal = No magnetic signature

Additionally, the foam acts as a buffer to keep water out of the cavity area of the shaped charge. Water and shaped charges don't mix.

[nbk2000]

US4693181 Linear cutting charge, which is the patent for the ECT, and gives some specs for the flexible copper liner.