Sciencemadness Discussion Board - detonate a small amount of RDX

detonate a small amount of RDX

Per - 19-5-2007 at 05:38

I just wanted to try if I could really make RDX, but just with a very small amount of less than 1g.
I think the preparation was successful, by adding cold water to the clear rection mix a white powder precipitates.

Now it´s nutralized and dry but by heating it just involves white fumes.

My question is, if it´s possible to detonate such a small amount (less than 1g!) of the very low sensitive RDX?

I wouldn´t mix it up with things like TATP because I want to see how strong itself RDX is.

Mr. Wizard - 19-5-2007 at 06:19

Try dropping someyhing on it, and measure the damage done to the anvil / hammer combination. You will be able to control and precisely repeat the 'input' to get a baseline. Then add your material to a small cup or depression in the anvil that was full of an inert material during the baseline tests. Measure the changes. You might measure weight loss, volume change, noise, height of rebound, or whatever you think you need.

quicksilver - 19-5-2007 at 06:54

Quote:

Originally posted by Mr. Wizard
Try dropping someyhing on it, and measure the damage done to the anvil / hammer combination. You will be able to control and precisely repeat the 'input' to get a baseline. Then add your material to a small cup or depression in the anvil that was full of an inert material during the baseline tests. Measure the changes. You might measure weight loss, volume change, noise, height of rebound, or whatever you think you need.

I completely agree. Impact testing is something you can do with little high-end equipment and works well to give you a baseline with energetic materials. I would suggest that you wrap the material in a one inch square fold of Al foil for containment and consistency. Impact with RDX will certainly yield a small pop.

Start with steel on steel if you intend to alter the surface as part of the test. Steel on steel will certainly work to begin with. RDX has been used with detonators. So a gram will most certainly respond.

Just as a note the strongest response to impact testing I have ever seen was with well made ETN. A very tiny bit that measured 5 mg. made an incredible noise! I was actually surprised when it was compared with RDX, PETN, & NG. All of which respond well to small scale impact testing......the test was fun. The amount was weighed and folded in foil of one inch square. The material was placed on an anvil and a large hammer was made to pivot with a nail through a hole in the handle. The hammer was dropped with no push on the sample. Thus the impact was fairly equivalent in each case.

Per - 19-5-2007 at 06:56

Do you really think that RDX is sensitive to blow?

I heared that you can shoot on C4 and it doesn´t decompose.

Mr. Wizard - 19-5-2007 at 13:31

The short answer is yes.

Microtek - 20-5-2007 at 23:16

I don't think that impact is suitable for quantitative testing of explosive power. Especially with small amounts of energetic material, I would think that the initiation would by non-uniform.
Instead, I think you should pack it into a small pipe and initiate it with a good primary. HMTD with silver acetylidenitrate priming works well if you don't want to prepare azides. When I say a small pipe I'm thinking 2-3 mm ID.
Then place the pipe against your witness plate of choice either end-on or side-on and detonate.
Don't worry about 2-3 mm being below the critical diamter of RDX; it may not propagate very far, but 10-15 mm is no problem even with very little confinement.

quicksilver - 21-5-2007 at 06:47

"Quantitative testing"? No, I agree, but it is interesting. There are so many [commercial] energetic materials today that simply do not initiate via impact, that sort of test is almost forgotten except at the development stage. The hot-spot concept in impact testing I find very entreating. This could well add baseline information to issues like EBW dets , etc. What's more, crystal size, shape and / or uniformity might be an issue which could add a whole different dimension to product synthesis. But the point is not without merit as ETN makes one Hell of a bang (via impact) but is not equivalent to RDX in VoD, etc.

Per - 21-5-2007 at 07:44

Thanks for your different replies
maybe it´s the best way to produce more RDX and test it on New Year´s Eve with black powder as initiator and a cracker[Böller], would blackpowder be enough to initiate RXD?

Also I would test with a little cristal if RDX detonates by dropping on a 350°C hot heater, hope that would be enough otherwise I´ll try the impact methode.

Mr. Wizard - 21-5-2007 at 07:53

The original question was to see if he had indeed created RDX without going through all the complication of trying to interpret the initiation from the material he was testing from whatever he might use initiating it. Most of us can tell when a 2.5 or 5 Kg hammer bouncing on a steel anvil from a meter high from the additional noise of a chemical decomposing suddenly. Try putting a single match head on an 'anvil' and hit it squarely with a hammer. Even wearing the eye protection and ear protection required, you should hear a different noise, see a different residue, and smell a different smell. It's not the Rosetta Stone of energetic chemistry, just a very simple, safe, and cheap tool.

The test won't even tell him what the material is, just that it 'does something'.
I can think of all kinds of variations that would give other useful information.

Microtek - 22-5-2007 at 02:33

Well, go ahead and use the hammer. I'm just saying that unless you have a reasonably precise drop hammer, this way of testing is not reliable. I often use it myself, but only to get a rough feel for the material. If you place the explosive in a fold of Al-foil and hit it with a hammer that is held in your hand, then you will get a lot of false negative results. And if you strike a sample more than once you add another variable.
With the method I suggested, you compress maybe 50 mg of explosive into a thin drinking straw (2 mm ID giving a coloumn of ca. 15 mm @ 1 g/cc ) then add a 5 mm coloumn of HMTD and prime it with some double salts. The straw is then taped side-on onto a piece of wood and a pencil is used to mark where the coloumn of supposed RDX begins and ends. When the charge has been initiated, you can clearly see whether the RDX was detonated or not by noting how long the indentation in the wood extends. You can also get an impression of how powerful it is by comparing the depression under the RDX with that under the HMTD.

quicksilver - 22-5-2007 at 05:32

Quote:

Originally posted by Per
Thanks for your different replies
maybe it´s the best way to produce more RDX and test it on New Year´s Eve with black powder as initiator and a cracker[Böller], would blackpowder be enough to initiate RXD?
.

You are going to need some material that produces shock via detonation or close to it.... BP won't do. The peroxides will work if you don't have a unique primary that you like. HMTD will do VERY well.

Per - 25-5-2007 at 12:10

Now I´ve tried the method with the hammer and I´ve of course just a normal hammer and a simple vice. So It doesn`t detonate at all.

The methode with the heater failed alos.

Firstly I wanted to avoid peroxides because two reasons, they´re unstable and I wanted to see how RXD explodes itself.
But now I think it´s the only way to decompose the unsensitive RXD conveniently.

garage chemist - 25-5-2007 at 14:59

Are you sure you do have RDX in the first place? It should deflagrate very rapidly if heated by a flame. If it doesnt, you dont have RDX.

There was probably something wrong with the procedure- the HNO3 must be of the best quality (vacuum distilled from H2SO4) and the temperature in the reaction must be high enough (unlike with other nitrations), etc...

Per - 26-5-2007 at 00:31

Well, my product is absolutely unsoluble in water and I´ve recristalisized it in acetone and it worked.

Also I tried this morning a larger amount of the "RDX", the last time I used a very small amount because safety first by working with higt energetic materials.
By using the larger amount I could recognize that the cristals burn down with a orange flame.

The strange thing is that I used a totally different procedure then yours. I used yellow ca. 98% HNO3 and cooled it down to about -20°C and then I dropped slowly the urotropin cristals in the cooled liquid. As wanted they didn´t bubble and after a while they were dissolved. After a day a dropped the now warm liquid into a ice bath and very little white cristals precipitated.
I cant imagine what should be produced otherwise then RDX, but sure will just be given by detonating it.