Making a HMTD blasting cap

[Dombum]

A few days ago i made some HMTD and started thinking about how to make a good blasting cap.And here is my idea!:)

1.At first buy a copper tube with the diameter of about 1 cm,and cut it to a length of about 8 cm.After that you cut a paper which is about 4 cm broad and is about 2-3 cm longer than the copper tube,like this:

http://www.pictureupload.de/pictures/080107203306_RIMG0030.JPG

2.Then roll the paper and put it in the tube like this:

http://www.pictureupload.de/pictures/080107203832_RIMG0032.JPG

3.Then press one end of the tube with some pliers together,and put the HMTD in the tube.But make shure that the HMTD fills just a bit more than half of the tube!!!that lookes than like this:

http://www.pictureupload.de/pictures/080107204543_RIMG0036.JPG

4:Now put a fuse(Normal fuse or electric)in the tube so that it touches the pressed HMTD.Than press the tube from the side where the fuse is together.BUT BE FU....CAREFUL WHEN YOU DO THAT!!!!!!HMTD IS VERY SENSITIV!!!!!when the tube is ready pressed and the remaining paper is cut off,it lookes like this:

http://www.pictureupload.de/pictures/080107205301_RIMG0040.JPG

5.And this s how that think looked when i fired it:D :

http://www.pictureupload.de/pictures/080107210024_RIMG0041.JPG

I hope i could help some people with their problems with blasting caps.If you have any question,just post it!!!cu domi

[knowledgehungry]

First off I would like to compliment you on doing some experimentation of your own, documenting it well, and sharing the information.

However there are some issues that I have with this post, first of all there are many existing threads dealing with this and if you had done a good search you would have found an old thread to post this in instead of starting a new one.

Secondly your grammar, while better than many, was certainly lacking in some areas such as capitalization of I, and minor typos.

My third issue is more with your blasting cap than your post, I can not recommend bending a tube with a primary explosive inside of it, apart from the danger of pinching the explosive and setting it off by force, when you bend metal it generates heat. Heat which could also set off your HTMD.

All in all I think you have great potential to be a valuable member here, we need more people to post there experiments with photos and the like, I am just trying to give you some feedback on how to make your stay here long and more beneficial to the forum overall.

[c.Tech]

From what I’ve heard left, right and centre HMTD reacts with metals creating heat that can set it off. Is this different with copper?

[vod8750]

I understand that he lined the copper tube with paper to prevent that from happening.

[mike16]

My blasting cap bodies are aluminium cut from cola cans, I cut the aluminium from the can into a 2 by 1 inch section, which is rolled and taped together, the end is sealed with selotape.

1 cola can will make 5 cap bodies.

I then carefully pour AP in the open end, then press it very hard in a long vice,
they are 9mm in diameter.

I dont use fuse as I have a remote electronic device with 4 different channels,
so I use nichrome wire.

Dombum, do you press your HMTD?, because there is a VERY BIG difference in power between a pressed cap, and an unpressed cap.

[Dombum]

Hey thanks for the advice knowledgehungry,yes sorry for my bad english,and mike 16,yes I do press it. At first I didn't press it and then it looked like this after the detonation:

http://www.pictureupload.de/pictures/090107215237_RIMG0008.JPG

But after I pressed it you can see in the last picture upside in the discription what happened to the tube:D

And about the danger that the HMTD detonates in your hands while making the cap, I said that the HMTD is not allowed to fill more than half of the cap, and because of the heat when bending the copper I put the paper inside the tube so the HMTD does not touch the metal!

And yes, I could have looked better in the searching engine.

But anyway my plan is to make a detonation with 1 kg ANFO,100 gr of ANNM,and this blasting cap I made. Do you think this b.c.has enough power to set of the ANNM?


Acronyms are always capitalized (ANNM, not annm), I is also ALWAYS capitalized when referring to yourself, as are the first letter in the beginning of a sentence.

And you don't make two posts withing minutes of each other in the same topic. You edit your previous post to include the new comments.

[nbk2000]

The fact that your cap tube is split, not atomized into particles, shows that the cap is weak, and inadequate to the purpose of setting of high explosives like ANNM, let alone ANFO.

[Alexires]

Dombum - Don't be caught out by thinking that only half filling it will protect you. What happens if a small crystal stays in the neck of the tube and you set that off?

Organic primaries are notoriously sensitive for a very good reason.

You would be better off using a more sensitive secondary to detonate the ANNM, and also using more primary in an easy to use plastic blasting cap. You would hate to have some left over acid or water soak into the paper and leech some copper in the HMTD wouldn't you?

In reference to above, while some might argue that more primary = less safe, I would prefer to use more primary than to have it PRESSED into a METAL container and CRIMPING the ends.

If you insist on using metal, try a harder metal, or Hard Drawn Copper. While it will cost a little more, it might give you better detonation results, and this is important when you are using it as a Blasting Cap.

My only accident with pyro has happened when dealing with UXO (Unexploded Ordinance). If hadn't been using plastic, I would have lost an eye.



Otherwise, Congratulations on joining The Forum. May your stay here be knowledgeable and injury free.

[Dombum]

Thanks nbk2000 for your advice.And Alexires,what do you mean with more sensitive secondary to detonate the ANNM?

[Grapes Of Wraith]

I think he means that you should have your blasting cap detonte a secondary explosive to increase its power, before it should even think about detonating the ANNM. So you should have three layers, your blasting cap, then some amount of picric acid (or some other secondary explosive) and then the ANNM.

[c.Tech]

Did somebody miss something with their replies?
My blasting cap bodies are aluminium cut from cola cans, I cut the aluminium from the can into a 2 by 1 inch section, which is rolled and taped together, the end is sealed with selotape.

1 cola can will make 5 cap bodies.

I then carefully pour AP in the open end, then press it very hard in a long vice,:eek:
Pressing AP very hard in a vice, not to mention being in a metal object whilst pressing is an incredibly dangerous and stupid thing to do. Phone didn’t even do that and he's dead.

It's only a mater of time before it dets and sends metal shrapnel heading towards your face and vital organs.

Have you got any idea on the sensitivity of AP?

[nbk2000]

Compression and shock are not the same thing.

The slow compression in a press (or vise, in this case) is not liable to stressing the bonds that hold the AP molecule together like a sudden whack of a mallet on the pressing rod would.

[mike16]

NBK is right, put a very small piece of AP on an anvil, and instead of hitting it with the hammer, carefully place the hammer on it and start to press down on it gently, it doesn't go off, even if you put all your weight on it.

Also, the caps are remotely pressed in the vise.

c.Tech, I may be new in this hobby, but I'm not some k3wl idiot that hasn't a clue on what hes doing.

[c.Tech]

Apologies mike, I didn’t fully understand your circumstances or the properties of AP, I've always thought pressure is as bad as friction and shock to an explosive.

[Alexires]

Grapes of Wrath - That is exactly what I mean. I was really just following on from NBK's comment that his det. cap would be incapable of detonating ANNM, let alone ANFO.

The answer to that (if you can't make a better cap) is to use a more sensitive secondary with more primary.

[Dombum]

Do you think pressing some HMTD in a cigarr shell that is about12 cm long and 1.8 cm in diameter will be enough for detonating the ANNM?And what are good secondary charges?

[Grapes Of Wraith]

You would have to do some tests on that but it might work. There are many secondary explosives availible it just depends on the chemicals you can get. Like I said before Picric Acid is a good one, because I think its just easier to make.

[knowledgehungry]

That is far more primary explosive than is ideal. Like everyone else has suggested, use your blasting cap to initiate a more sensitive secondary to set off the ANNM, there are a few that I can suggest; MHN, NG, PETN, ETN as well as picric acid. ANNM is just not that sensitive.

You might even be able to use PVN to set it off (there is a thread currently active on its synthesis from Elmer's glue), although it is relatively weak (for a secondary) you can use larger amounts of it safely. I am not sure of the sensitivity, Mega's Lab says it is medium, but his lab says that AP and NG are both very high sensitivity, and they are worlds apart.

[FullMetalJacket]

My blasting cap bodies are aluminium cut from cola cans, I cut the aluminium from the can into a 2 by 1 inch section, which is rolled and taped together, the end is sealed with selotape.

1 cola can will make 5 cap bodies.

I then carefully pour AP in the open end, then press it very hard in a long vice,
they are 9mm in diameter.

I dont use fuse as I have a remote electronic device with 4 different channels,
so I use nichrome wire.

Dombum, do you press your HMTD?, because there is a VERY BIG difference in power between a pressed cap, and an unpressed cap.

Although it's been stated that pressing it is safe, what about pressing an organic peroxide in direct contact with a metal like aluminium? Granted, the oxide layer probably makes things a bit safer, but I've always been told that OPs and Metals are about as safe as mixing conc. sulfuric and potassium permanganate in your mouth.

[Kleng]

Nice to see such a topic. Planning to make some blasting caps myself.

I'm going to use an organic peroxide as the primary, and some quite sensitive explosive as a secondary. Probably TNP or ETN? I can make TNP, but it costs alot. ETN is much cheaper, as I can buy Erythritol cheap. Is there any others I should try instead? I think I can get the chemicals for NG, EGDN and PGDN.

I want to use the detonators to try to set off some PLX og NM/HNO3. I know the last mentioned is quite sensitive, and doesn't requires a big blasting cap.

And I've allways thougt that aluminium is quite safe to use as a casing for detonators. Other metals, such as copper, is not good.

[bizon]

I have fired abou 10 ANNM charges in last few weeks. I must say it is more sensitive, then I thought. I started with 1,5g HMTD, and now I am on 0,8g and had no missfire so far.
But the fact is, that I use paper detonators (5 layers of paper, diametre of cap is 0,8cm), and metal container can behave different. So I don't say that 1g is enough for you, but at least you have some data to start with.

[knowledgehungry]

I have never had any trouble with AP and metal, I knew someone who used to use .22 shells as blasting caps with AP and never had any trouble. HMTD behaves differently with metals than most organic peroxides, it has a very different chemistry.

I would recommond that if at all possible stay away from metal with AP, and under no circumstances use HMTD with metal.

[Cindor]

I use plastic pen cartridge for my detonators and I never have any trouble with them.

I don't like to mix metal and primers, just for safety...

If you are specting that you device would go off at any second, then you'll be prepared and when it go off nothing unexpected happens, like pieces of metal going throw your body.

[Dombum]

Today I ordered 1 liter of NM.I will set my first 100 gramm ANNM charge off as soon as the NM arrives.I think it will come the next week.I will use a drinking straw filled with HMTD as a det.lets see if it works.I will make some pics and a vid so I can show you guys if it worked.

[FullMetalJacket]

A drinking straw will not give you enough confinement.

[mike16]

A drinking straw should work, as long as your HMTD is dry, IIRC most primarys don't need much confinement, if any.

Though I'm not quite sure on HMTD, as I've never made it, but I know AP would work.

Dombum, why don't you try making small amounts of AP, and use this as I've heard it is less reactive than HMTD.

[sprocket]

If you use a drinking straw most of the confinement comes from the secondary explosive surrounding the detonator. Although just the drinking straw would provide sufficient confinement for detonating HMTD as long as you seal the end where ignition takes place properly.

I've successfully detonated ANNM using HMTD in a McDonald's drinking straw (6.5mm ID) several times. One end is sealed with cement and the straw is filled with 3cm HMTD pressed at ca 30N (I know this is a low force, but hey... it works). The other end can be left open, but for practical reasons I seal it with either tape or plastic explosive. This simple detonator has a good success rate, but it's hardly reliable.

It seems the thin wall of the drinking straw is actually beneficial, because these detonators are more reliable than a variation using plastic pen casings (6.5mm ID, 1.1mm wall thickness). I don't know if it's just coincidence or if the thicker walls actually have a significant effect on shockwave propagation.

I'm currently working on adapting this detonator using a bridgeless electrical igniter similiar to frogfot's (http://www.frogfot.com/pyro.html#elig). I use a single conductive pyrogen (as opposed to frogfot's two layer solution) based on aluminium, potassium nitrate and nitrocellulose lacquer. Now, for some reason I have this idea that HMTD should under no circumstances come in contact with NC. Is this true?

[knowledgehungry]

It is not coincidence, the thinner the wall the better the propagation of the shockwave.

[Gerbil]

Dombum, why don't you try making small amounts of AP, and use this as I've heard it is less reactive than HMTD.

HMTD is both more stable and powerful than AP. It's also, in my area, easier to source the chemicals to make it.

[stupid939]

Gerbil, here is what NBK has to say about AP vs. HMTD


HMTD is much more dangerous than AP, and not worth the risk.

I'm guessing that if anyone would know, it would be NBK. So you can save your hexamine for RDX or something.

[knowledgehungry]

HMTD may be more stable, but more dangerous at the same time. HMTD's greatest danger is in its reactivity. AP may be less stable, but it doesn't carry the same risks from contamination as HMTD.

[Gerbil]

hmmm, interesting. I honestly haven't heard anything about how reactive either compound is before. I thought that contamination was only a danger when it came into contact with metals?

I've stayed far away from AP for safety reasons, after all, even mega's lab states:

It can not be stressed enough how unstable and dangerous acetone peroxide is. As instability goes this is among the most unstable of other explosives here.

Maybe it's time to find an alternative to both of them :p

[Cindor]

AP is less sensitive than other primaries like MF.

[nitriees]

I always use drinking straw to make AP or HMTD detonator with slightly press, so far 100% successfully go off. It is sufficient to set off 1:9 ratio of AP/HMTD : AN booster.

[nitriees]

I have a bottle of AP which immerse in the water and store at room temperature ( 26-30 degree celcius ) for more than 3 years now, take some sample out, dry it and tested found the quality still same as the fresh made.
Another dry sample store in film canister at room temperature for 6 months, still in good quality and no traces of recrystallization on the lid. Of course the AP are neutralized and wash properly before this storage experiment.
The HMTD I made only storageable if immerse in water and store in the refrigerator for few months, when I bring it out to room temperature for few days, it will all decompose to dirty milky liquid and unable to recover back. The dry HMTD only survive for few days at room temperature and start to degraded in quality, it just burn into fireball even with confinement. That's why I only use fresh made HMTD for detonator and use it within 3 days for good quality. This is storage experiment for quality test only, I'm not recommend the storage of any peroxide primary.

[sprocket]

In my experience dry HMTD can be stored in an open container for months at 20°C without losing too much potency (certainly detonates, and the loss of mass is insignificant). Considering what happens to your wet HMTD, humidity might be an important factor. Do you live in a region with high humidity?

Perhaps the storage stability of HMTD detonators could be improved by adding a dessicant to the primary.

One important effect of storing (dry) AP is crystal growth, since this has a significant impact on the sensitivity. I found that after storing AP for over 6 months crystals in excess of 1mm in size had formed. Is this consistent with your observations nitriees?

[Chopper]

Guess the devil's in the details, as always.

I've a similar experience to sprocket in the storage of the stuff. I've had a sample sitting in open air for about 12 months now. There is absolutely no discernable difference between this batch and a brand-new "just finished drying it" batch.

I've also had success in plasticizing it with the clear sticky substance used to hold bluetack together. Extracted with shellite and decanted, this stuff after the solvent (Shellite) has evaporated, resembles the stuff used to hold cds to the cover of magazines. This plasticized mass has been stored for over 6 months with no visible bloating or foaming due to decomposition.

The only time I've ever had problems with the stuff is when I used to neautralize it with bi-carb. I found it really hard to remove all traces of the bicarb and after about 2 months, the hmtd was a different beast all together!! The powder clumped somewhat, as did it detonate with a different colour and more tellingly, with a different smell. It smelt like burnt coal, much like a steam train!

The last couple of times I bothered with the stuff I just decanted, filled with water, allowed to settle then repeated. I reckon I decanted 50% of the water each time, repeating about 10 times. I figured that about 0.09% of the citric and unreacted h2o2 would remain. Certainly more dilligent than many without fingers have been.

The great stuff about the hmtd-tak was that it was waterproof, didn't need containment, had a far higher density than I could achieve by pressing and worked a treat inside drinking straws. Never did quantitive tests, but there is a distinctly different sound observed when pressed dry powder is detonated, and when this sticky explosive is det'd. The dry powder is much less painfull on the ears..

It also made for some really interesting experiments, somewhat akin to explosive forming used in the aeronautics industry. Take a _small_ chunk of the hmtdtak, smear onto a 1" square piece of coke can until it's about 1/2 a mm thick. Place coin against aluminium side and detonate. By not using too much, i.e plenty less than 0.1g, I could get a perfect reproduction of the coin's surface - right down to scratches and the engraver's mark. It was really amazing to see such detail reproduced on the back of a cougar or beam or coke can. With the right amount, you could even get the edges to be cut off, leaving you with a perfect circle or whatever shape the coin had.

[sprocket]

The only time I've ever had problems with the stuff is when I used to neautralize it with bi-carb. I found it really hard to remove all traces of the bicarb and after about 2 months, the hmtd was a different beast all together!! The powder clumped somewhat, as did it detonate with a different colour and more tellingly, with a different smell. It smelt like burnt coal, much like a steam train! This is a good observation. While it is important to properly neutralize and wash nitric acid esters and some other nitro compounds it doesn't have to be the case for organic peroxides. On the contrary, I think it's actually beneficial not to neutralize the organic peroxides. Instead, just rinse the product with water two times and methanol the last time when it's in the filter.

Of course, it is somewhat circumstantial. Having significant amounts of sulfuric acid in the product probably isn't very beneficial, but suppose you used a more volatile acid...

How would you guys mix the AN with the NM?And how long does it has to soak in?And where in?
This really is a question for another thread, but simply put: Just mix the two in a plastic bag (for small to medium sized batches). Performance and soaking time depends on several parameters, most importantly particle size, porosity, ratio and temperature. Generally speaking on the order of 30 minutes is good, but more is better.

[Microtek]

My advice to anyone who is using primaries on a regular basis is to find something better than organic peroxides. I used them myself for a number of years until I found something better, and thankfully I was never seriously injured.

In the end it was the awareness that a detonator could go off at any time as I was transporting it to my blasting site that made me search for better alternatives. What I ended up with was different sorts of clathrate structures, as introduced by Roscoe Bodine on SM. These compounds can be tailored to suit almost any application by adjusting the proportion of azide in the structure.

Now, I realize that sodium azide may appear to be out of reach for most of those that still use peroxides, but it isn't really very difficult or dangerous to synthesize ( certainly not as dangerous as handling peroxides ).

The azo-clathrates can be made both sensitive and powerful by using a high proportion of azide, but the true value is in my opinion that by using somewhat less azide, a compound that is less sensitive than RDX in all regards except flame or spark sensitivity ( also less sensitive with regards to static electricity ) can be produced. This means that you can make a detonator that can be hammered flat without going off.

I have also experimented a little with clathrates based on nitrotetrazoles with promising results.

[nitriees]

Sprocket, the room temperature and humidity of my environment is very high, may be this is the main cause of dry HMTD quality degraded within short time of period. The dry AN in sealed container will turn wet even with minimal air space inside. The material I used for synthesis are quite pure, 50% H2O2, food grade citric acid and purified Hexamine by recrystallization.

By observation, the 6 months old dry AP in closed lid film canister don't form any different size in their crystal form, it still very uniform fine powder and no traces of recrystallization on the lid or container surrounding. The precusor used are pure Acetone, 50% H2O2 and 33% HCL with < 5 degree celcius temperature control during whole synthesis process.

[DMSOnMyVeins]

I don't experiment with energetic materials, however, after reading this topic I got an idea to use aluminum or PTFE rods to make a more professional blasting cap than using drinking straws or aluminum cans.

Why not use aluminum rod stock such as is available at Home Depot, cut the rod to length, then drill out the rod to a shorter depth than the length.

PTFE rods are available from several online outlets and should be able to be used if your primary can't be used with a metal cap.

[nbk2000]

There have been numerous accidents involving HMTD in binders, most often Ping-Pong ball NC.

Whether it's acidic contamination or some other factor, who knows, but adding binders to HMTD is generally considered a bad idea.

[Dombum]

Ok,today i mixed the ANNM.I put 100 gr into an plastic bag and tied it very hard with tape.As a detonator i used a small drinking straw full of HMTD.I thought it wont work,but then i burried it with mud and lighted the fuse...after a few seconds of stupid waiting:confused: ...BOOOOOOOOOOOOM:eek: Fuck me!!!I ve been about 15 meters away and got a stone on my hand!!!That was as loud as... i dont know!!!wooah shit ok.Now I know it works with very small amounts of HMTD in a drinking straw.The hole was big,and slight white smoke came out of it:D this is the best feeling ever when you feel the det.in your brest,you know what I mean:cool:Yes and now the bigger charges will be 150 gr., 200 gr, and 300 gr,but I dont know yet where to detonate them.

[FUTI]

DOMBUM!!! You used weight of explosive higher then used in a hand granade and then choose to stand within a kill zone of the hand granade. What you think you are? A cat maybe?

I know that AN based explosives aren't that powerfull as one used in hand granade and also that you covered it with mud (where AN based explosive show best performance I think). When I make experiment I first try to guess what will be the worst case scenario and then stay out of the danger zone by all means. How deep that was burried? I guess not more then a foot since you said mud and if it was more than a foot of mud you were in the swamp.

[Alexires]

Dombum - I see you're excited. Congratulations on a success. In addition with what FUTI said, you also might want to consider researching the MINIMUM amount of HMTD required to det AN. The less primary the better for your health.

IIRC .75g of HMTD is the equivalent of a #10 Re-inforced blasting cap, so maybe a drinking straw full is a little overkill?

Nitriees - Don't self sign posts, sort of one of those unwritten rules (that have been written somewhere).

Microtek - I did a forum search for clathrates and found nothing directly relating to them. Would you mind perhaps giving some details of your experiences with them so that those of us who currently use organic peroxides may consider another course?

I'm not asking for spoonfeeding. I fully intend to do my own research, but any extra help from someone who has actually made/used them would be greatly appreciated I'm sure.

NBK - Thats interesting, because the praises of AP-putty have been shouted to the high heavens, yet another organic peroxide with NC is unstable. Any idea why people?

Perhaps it is the amine groups (which is really the only molecular difference between the two other than the O-O bonds in AP)?

[knowledgehungry]

The amine groups on HMTD are a pretty big difference in reactivity, especially when you compare it to a methyl group on AP. All of AP's reactions are going to be based on the Oxygen bonds as opposed to the C-H bonds.

[nbk2000]

http://www.roguesci.org/theforum/showthread.php?t=3158&highlight=clathrates

[Shalashaska]

I had an interesting thought earlier this week... How about the capsules in coin machines near the exits of department stores? They seem perfect for the job, since they are all kinds of sizes from approximately 3/4" to 1.5"

[nbk2000]

And what 'job' would these capsules be used for?

[Shalashaska]

Depending on the size of your charge, you could use it as a blasting cap. If you've got something one of the larger capsules could fit into, you could use the small one as a blasting cap in the center, and put a more potent explosive in the larger one with the small one inside it. This is pretty hypothetical, since I haven't been able to order any ammonium nitrate to test some blasting caps and boosters with ANFO or APAN. Or do any of my farmwork. I'm getting behind... :(