posted February 15, 2000 11:51 PM            

if someone was trying to blow them out what would someone used to try to attempt something like this.
something that can be made at home.

posted February 16, 2000 11:06 PM            

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posted February 17, 2000 06:52 PM            

will that set off the anfo

posted February 17, 2000 06:56 PM            

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posted February 18, 2000 03:01 PM            

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posted February 18, 2000 04:02 PM            

thanks for your help so far guys

posted February 18, 2000 04:08 PM            

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posted February 19, 2000 12:27 PM            

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posted February 19, 2000 07:59 PM            

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posted February 20, 2000 09:19 AM            

this is probably a retarded question but say you have a bucket full of AN prills from fertilizer. do you use a 17:1 ratio and pour say 1 cup of deisel into the prills then mix the stuff up or what.

also does regular unleaded gasoline work for this or is it too sensitive? i know the ratio would change as compared to deisel if the densities are different but i was wondering if it would be too volatile or somethin like that.

posted February 20, 2000 10:56 PM            

take 17 cups of ammonium nitrate and mix with 1 cup of diesel..

posted February 21, 2000 08:41 PM            

and if you use more anfo it will det better.

For what its worth here's most of what I learned.

It is slow, meaning it pushes stuff rather than shatters it. It also pushes itself apart so that small quantities will not go except right around the booster.

The most sensitive mixture I ran across was discovered by Cook. He ground the AN fine, and added 1% by wt of some wax. Yes 5 to 6% is a balanced mix, but it dampens the surface
wave and takes a much stronger wave. The wave I speak of is a pressure pulse that is capable of raising the temp of tiny air bubbles in the expl to white heat or more. This temp then decomposes the AN. In a big quantity a true detonation wave can get going.

Generally ANFO will not go very well in bore holes less than about 6 inches diameter. It will go in 4 inches diameter if fine, and well mixed with sensitizers other than liquids. Liquids take a bunch of heat to vaporize before their temp can really soar.

Anfo mixed with 10% commercial dynamite is a slow and easily set off explosive that will go in about 2 inch diameter boreholes. Call it FGAN helper. FGAN = fertilizer grade AN.

Stump blasting was usually done with chlorate sugar mixtures by early farmers. It is also a slow pushing type of explosive, and almost as good as ANFO, but more expensive.

FGAN can be made to go completely using the gas booster system. In a 14 oz propane cylinder, filled with FGAN, and having a 1/8 inch copper tubing fitted to the tank, and a half inch hole drilled in the tank with a half inch nut soldered to the tank to allow you to seal the hole after its filled, with a bolt and gasket, put in prilled FGAN till completely full.

Next, seal it pressure tight with the bolt.

let the copper tubing be about 10 ft long.

Bury the tank about 5 ft deep, and on the top side make a fitting with a model airplane glow plug in it, and also the air conditioning fittings used on autos, to fill it with gas. You must have a pressure gage on the filling device that will read to 300 psi.

Next, fill the tank with propane till it reads 100 psi.

Next attach oxygen to the tank and fill it till the gage goes up from 100 psi to 300 psi.

seal off your gages, and wait about an hour for the gasses to mix. It is slow because they must mix by diffusion, and if not mixed it will be a dud.

When the time is up, vent a tiny bit of gas from the filler, to blow the pure Oxygen out of the tubing and fill it with mixed gas.

Doesn't take much for the volume in the tiny tubing is very small.

If you bleed this out through a tiny orfice like that used in the propane torch burner, you can light it as it comes out and when it will burn, and you can stop. Otherwise gage how long to let it leak by bubbling the exiting gas into a inverted coke bottle, and when its volume is a bit more than the volume of the tubing, quit.

If you have this 5 ft deep, it will only cause a mound in the dirt about half to a foot high, and a thump.

Less deep and it can throw stuff around.

Test it to begin with at least 5 ft deep so if you screw up you will not be hurt, but you might be jostled as the ground around you heaves up about a foot. When you are more sure what you are doing you can use it at lesser depths.

To set it off you put power to the glow plug. That lights the gas in the tubing, which will flash down to the cylinder, and The 300 psi gas mix will instantly go to about 2000 psi, and 5000 degrees F, and that will touch off all the FGAN in that size cylinder.

I never had any luck setting off smaller amounts no matter how I tried to get FGAN and a sensitizer to go, unless the sensitizer itself was an explosive, that could carry the
FGAN along in its own explosive wave.

FGAN and AN are more explosive extenders than real explosives, unless you are using ten or more pounds at a shot.

Dupont nitramon, popular in the 50's used 4 inch cartridges of tin, about 3 ft long, filled with AN and a sensitizer fuel. The booster to set it off was the same size cylinder filled with TNT. It was used a lot in mining.

It was very safe, and was commonly stored on the ground in large mounds of cylinders, for rifle fire would not set it off, and forest fire would not either, in those thin tin containers.

Generally, research on accidental explosions of FGAN showed it had to reach a temp that was causing it to vaporize, and simultaneously some sort of fuel had to ignite in it to cause the pressure to go above about 200 psi, and then a detonation wave could begin in the gasses, which would transfer to the solids, and the whole thing would go. The texas city accident involved a ship load of it, which caught fire, and after burning quite a while it went, and leveled that town.

So, with ANFO, big is good, and small is nearly impossible. Its fairly safe to play with for its nearly impossible to get it to go with much violence unless you are using a lot of it, and its very well confined.

One could possibly use the technique of putting FGAN and some fuel in a cylinder that could take about 500 to 1000 psi to rupture, and use black powder or any other powder to get it going, and the cylinder would hold it together till it all got in on the act and that could do the job.

Remember that propane cylinder discussed above contained about a quart of FGAN, and a couple pounds, and it moved a circle of dirt about 6 ft diameter and 5 ft deep, but didn' throw it out of the hole, It just raised up about a foot, and sat right back down where it was, but it was then loose, and a shovel could work on it.

Incidentally if you have the FGAN or any other AN at a temp above 85 F, it goes much easier, for it changes crystal lattice form at that temp, and expands some, and that form is more sensitive.

If you get it up to near its vaporizing temp, it becomes very sensitive, but most initiators would go long before that temp was reached. You could have an accident though by dropping into a molten batch of it some initiator like a cap. That would set the whole batch off big time. Even a rifle primer might do that, so do be careful with molten AN. Yes they melt it to pour into military shells, etc. The also melt mixtures of it with aluminum, in artillery shells, but you have close temp control to pull this off safely. No kitchen technology ought try that.
Takes an enormous booster to set off the molded stuff, in a shell casing.

Sensitizers I used were:
sulfur, good,
napthalene (moth balls powdered) works.
chlorobenzene moth balls powdered also works.
parafin works but is messy to get evenly distributed.
Gasoline, alcohol, diesel, kerosene, tar, rosin, work, but less well than the above.

The density is critical for max sensitivity.
Density about 1 is best. meaning pack it till it weighs about 1 lb per pint, or 1 gram per cc. It will have lots of air in it to carry the fire to all parts which the compression wave of the booster reachs, so it all goes off at about the same time.

In many explosives density is critical. the air bubbles are needed to ignite the stuff as the pressure wave hits. Rolling dynamite sticks to force air bubbles into the settled down stick raises its sensitivity a lot.

For example nitroglycerine will seldom be detonated by putting a drop on an anvil and hitting it with a hammer, but if you put the drop in a piece of paper tissue, and hit it you get a roar. The hammer can't hit hard enough set off the drop, but it sets off a tiny bit in the center of the hammer face, which blows away all the rest, and you get nearly nothing but a faint smell of smokeless powder. With the paper though it can't escape, and the air bubbles take it all off.

This principle is valuable in making fireworks, out of powder, as well as in making all powdered explosives. Watch the density...

but...

once the detonation wave gets out of the booster and into the AN, and its sensitizer,
that has to be able to sustain it or all you get is scattered AN.

As I said if the density, and sensitizer is ok, and IF the diameter of the column of AN that has to carry the wave to the other end is large enough all goes well.

Anything less causes the wave to dampen and cease a short distance from the booster.

Each combination of AN and sensitizer has a different critical diameter that will propagate a detonation wave. All of the sensitizers work if the stuff is in large columns, like barrels, or tank cars, or even cargo holds of ships. Almost none of them work for 1 inch columns, but nitroglycerine at about 20% and An about 80 % makes a common coal mine blasting dynamite. I think its called monobel. It goes in 1.25 inch sticks from a #6 cap. Incidentally a #6 cap contains 1 gram of a primer made from 80% mercury fulminate and 20% potassium chlorate, (the original cap) or its equal in initiating power of other modern primers.

Or in other energy terms it contains about 650 watt seconds of energy, and it can be equaled by large capacitors storing that much energy, and allowed to spark inside an explosive where you would put a cap normally.

the spark is normally carried to the explosive through coax cable used for CB radios, such as RG 58, which when cut flush will spark over at about 5000 volts.

Another way is to put a fine wire bridge shorting out the coax, or other cable, at the exposion end, and discharge electrolytic caps. If you select large ones that can take 450 volts, then the formula for the energy is
1/2 C V squared, where C is in farads.

650 watt seconds would take 6420 microfarads,
or about a dozen 500 microfarad 450 volt capacitors charged to 450 volts.

This has been used in some research to save on the expense of caps, but the cost of the machine requires that you intend to fire thousands of shots for it to be worth the effort.

Incidentally such sparks are used to fire more sensitive primer explosives in military ordnance. They need to be very much less for that, and can be the spark from a small cap charged to a few hundred volts. Such "caps" are not sensitive to strong radio transmitter fields, as are those which have a fine wire that heats up from the firing current. Military ordnance is around a lot of powerful RF current transmitters so they need a different way to fire things.

posted February 24, 2000 01:13 PM            

if you had a metal tube or box with one end open (say 12" diameter) and you are going to bury it and have it just blow a bunch of dirt up in the air for effect, it would be best to put the blasting cap deepest in the ground right? so the wave will propogate towards the ground and blow all the dirt upwards... this would not be to blow the metal tubing apart but to have the force exit in one direction (up). any ideas? i want like a dirt cannon kind of effect, not to make a crater in the ground but there will just be a hole (the box or tube) and all the dirt will be blown straight up in the air.

with that in mind i was also wondering about partial detonation of anfo... it has been kinda unclear to me how this works. if you don't have the stuff confined it blows itself apart right so then it is not dense and doesn't continue to detonate. the question i guess is if you had the blasting cap at the bottom of the hole with AN compacted down in the tube on top of it would this work as far as using all of the AN or would it be prone to a partial detonation if the blasting cap is too small?

or just say you had a small blasting cap... is it possible for it to cause a reaction using some of the AN and then stop because it was too small? or is the AN strong enough to continue to detonate? like if you had a tube a mile long filled up with AN and the cap was too small, it would either not do anything, or it would partially detonate, or it would get part of the AN to detonate and that would take the rest of the mile long tube with it. or would it be possible to partially detonate and take part of the tube with it and the amount of AN used in the tube (the length that the AN was detonated inside the tube) would be proportional to the size of blasting cap you used?

man i cannot think of a good way to put my question... any ideas though? the problem with the blasting cap is of course that it would be homemade for someone who can't buy them and thus might be too small.

posted February 24, 2000 06:48 PM            

using powdered ANFO (ive never done it) would raise the density over 0.8 (prilled ANFO) and probably be more likely to detonate from a #8.

If you poured a big trail of ANFO it wouldnt detonate along the line as yes it would scatter, and obviously you cant make det cord with anfo. but if confined in a thick pipe of a fair diametre ANFO will detonate ANFO..

as always with ANFO the bigger the detonator the better the boom..

I think the biggest problem most have is mixing the stuff up right, if its not mixed consistantly its easy to fail.

When i started this post i thought i had something useful to say....... oh well. bugger it.