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Author: Subject: Det Cap Strategies
Sir_Gawain
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[*] posted on 26-2-2024 at 10:11


Damage depends greatly on the hardness of the steel test plate. Also, it looks like you (LL) used steel detonator casings, while ManyInterests used thin plastic. I have a feeling that would greatly enhance the power.



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[*] posted on 26-2-2024 at 12:03


Sir_Gawain........Yes, metal cavity provide much harder results.



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[*] posted on 26-2-2024 at 20:35


Quote: Originally posted by Laboratory of Liptakov  
How were thickness of plate? 1,5 or 2 mm? Anyway, the your hole is weak. 1g ETN must causes circle hole minimal 10 mm. On second photo is plate 2 mm and 0.4 g ETN.





Quote: Originally posted by Sir_Gawain  
Damage depends greatly on the hardness of the steel test plate. Also, it looks like you (LL) used steel detonator casings, while ManyInterests used thin plastic. I have a feeling that would greatly enhance the power.



The cap that caused that damage used no ETN. It used 0.9-1g of NHN-sodium chlorate (6:4 ratio) as done using this: https://www.sciencemadness.org/whisper/viewthread.php?tid=15...

I used a 7mm ID 304 stainless steel capillary tube for the cap for both charges. the length of the one used with NHN was 50mm in length. I stopped using plastic pen bodies a long time ago. They simply don't fully detonate and simply sound like very loud firecrackers.

I didn't use a booster with it. as I wanted to test its power on its own, and the guy who came up with the composition did say it was good enough for ammonium nitrate secondaries... I am not entirely sure, but it is still powerful.

I did use a large ETN charge (1.1g melt cast + 0.3g + 0.5g of straight NHN), and it is what caused the damage to the other test plate. it blew part of it away (never found that piece) and didn't make a clean hole, it warped it to bits. I assume what happened is that it heated up the metal and then the snow caused rapid cooling? Thus deforming it greatly. Either way that cap (100mm long) is extremely powerful and I have great confidence in that it can set off almost anything.

I want to experiment more with the NHN composition. I think it does have good potential in and of itself. But if it is more powerful than straight NHN, then I can make more compact ETN detonators. Instead of 0.5g, I can I use a smaller 0.2g (or maybe 0.2g of straight NHN is sufficient to set off the 1.4g total ETN charge?).

Either way I am itching to see if a simple 0.5g ETN cap can set off ammonium picrate. and to see how much damage a 0.5g ETN cap can do.

[Edited on 27-2-2024 by ManyInterests]
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[*] posted on 26-2-2024 at 23:30


I suggest that you do a simple non-experimental cap first. Something like 1 g of pressed ETN or RDX, 0.3 g NHN and 0.1 g silver acetylide nitrate or other reliable DDT material. Fire that against your witness plate to establish a baseline (obviously do 3-5 repetitions), and then test your experimental caps against the baseline to see if they are an improvement or not. In general, clean holes are an indication of excess power, whereas big warped holes mean that the cap only just has enough power to poke through.

Regarding the ability to initiate AN compositions, that is not very telling in itself. Some AN composites are quite sensitive to initiation even without adding other sensitive explosives (nitromethane and aluminum of appropriate size and morphology comes to mind). If the NHN/chlorate cap is able to initiate ANFO or emulsion type explosives (unlikely) then I would be inclined to agree that it would probably also initiate ammonium picrate.
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[*] posted on 27-2-2024 at 07:20


I will do that. I try my next attempt with 4 or more caps. I am running low on NHN and I only have NHN as a primary. I have calcium carbide but I don't have have silver nitrate to make SADS. So I will have to do with a 0.3g of nhn-chlorate. I have another trip planned in a few weeks so I hope to make it count. It both exciting and kinda frustrating at the same time to not have these detonators perform as I hope they would.


I will also make some smaller caps for testing as well. 50mm the equivalent of a no. 8 blasting cap (0.5g of ETN to 0.2g of nhn-chlorate). I hope I have enough NHN to make that work. But I got time. I can make more NHN.

I wonder what I am doing wrong?

Edit: at this time I will agree that nhn alone, even improved nhn compositions, are not good enough for ammonium picrate. If I do try to set off an ammonium picrate charge I will need one of those larger composite caps.

Also I will glue the cap into place on the surface to allow for a better test. I will post pictures of how it will look like soon.


Edit2: I just wanna go on a mini rant to express my frustration. While I have improved the performance of my stuff, I am still baffled as to why it isn't working as I hope? NHN was supposed to be easy to set off other stuff and all documentation says it goes off in a cardboard body. Why would it have issues with a simple secondary like ETN? Especially meltcast ETN.

Rant over. I am sure I will find out what is happening and then make them work properly.

You did mention SADS as an additive to NHN. SADS might be a bit too sensitive for my liking, but I am curious as to how stable it is for storage? Since I often can go months without being able to test anything. The caps I used in this test were made last summer, btw.

[Edited on 27-2-2024 by ManyInterests]

[Edited on 27-2-2024 by ManyInterests]
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[*] posted on 27-2-2024 at 11:48


Quote: Originally posted by ManyInterests  

I just wanna go on a mini rant to express my frustration. While I have improved the performance of my stuff, I am still baffled as to why it isn't working as I hope? NHN was supposed to be easy to set off other stuff and all documentation says it goes off in a cardboard body. Why would it have issues with a simple secondary like ETN? Especially meltcast ETN.



To what density are you pressing your primary? The density of your primary composition has a huge impact on the power your device will produce.
Why do you say 'especially melt cast ETN'? Melt cast ETN will be harder to initiate than powdered ETN.
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[*] posted on 27-2-2024 at 13:15


If you have metal cavity, you can use only hand pressing (cca 20Kg) for output segment of ETN. For example 0.3 g. And for starting segment is possible use powder 0.15 ETN + 0.15 NHN. As 2 powders together. Thus 1:1. Heterogenous mixture. And hand pressed on 2 Kg. Should by works. Reliability this design was confirmed repeatedly. If it will not works, is error in quality NHN.....:cool:



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[*] posted on 27-2-2024 at 13:25


I am aware that melt-cast ETN is harder to set off. Hence why I also included some powdered ETN on top.

I am also aware that nhn would need to be pressed to a decent density but I am almost embarrassed to admit, I don't know how to calculate that.

My process for making an ETN blasting cap is to first put in the ETN that is to be melt-cast, and then tamp it down and give it a solid press by hand. Then I insert the tube into a beaker of water that is heated to, and maintained at, 70C and I give it around 7 minutes (usually a little more) to fully melt. I calculated that time with plastic pen bodies where I could see the ETN melting inside it. Steel is a better conductor of heat so it probably doesn't need that much time, but I give it that much just to be sure.

After that I CAREFULLY take the metal tube away and put it in a holder for it to cool down. Molten ETN can be more sensitive than TATP so I am very careful here. I give it around 20 or more minutes to fully cool down and solidify.

After it solidifies and is back at room temp I add more powder ETN, tamp it and press it moderately by hand. After that I put in the nhn piece meal and take breaks to tamp it down. After it is fully tamped I give it a solid press until I cannot feel it go down any more.

This step of the process is why I chose insensitive material to work with as I fear it will detonate on me. But I do give it progressive presses to bring it down.

Then it is inserting the e-match and applying instant epoxy to seal it.

I don't know how to calculate what density everything is save for the melt-cast ETN. Since it is melt-cast it is at max density, but I don't know about the rest.

If you can help me calculate this stuff and have better techniques that would be great.
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[*] posted on 27-2-2024 at 13:55


Quote: Originally posted by Laboratory of Liptakov  
If you have metal cavity, you can use only hand pressing (cca 20Kg) for output segment of ETN. For example 0.3 g. And for starting segment is possible use powder 0.15 ETN + 0.15 NHN. As 2 powders together. Thus 1:1. Heterogenous mixture. And hand pressed on 2 Kg. Should by works. Reliability this design was confirmed repeatedly. If it will not works, is error in quality NHN.....:cool:


My NHN is good. I do have a bad batch that I plan on disposing of (with sodium hydroxide solution). Then I will make more once I make more hydrazine sulfate.

I bought some nickel nitrate and I saw some information that to know how much nickel nitrate solution you must use to the freebase hydrazine you can keep adding until no more nhn is formed in the hydrazine (and you can see the nickel nitrate floating in solution).

Am I onto something here or am I being mislead.

Also your system for mixing ETN and nhn to make one mixture sounds like the simplest thing to do, and I trust you impeccable. 2kg is an easy thing to press and I can maybe do a little more.


Edit: I assume your mixture of ETN and NHN will mean the old composition of nhn-sodium chlorate is not necessary anymore. I did make a mix a long time of ETN and NHN but it was to make sure that they work together. They burned quick in the end and vanished without a trace!
[Edited on 27-2-2024 by ManyInterests]

[Edited on 27-2-2024 by ManyInterests]
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[*] posted on 27-2-2024 at 15:44


The e-match should ignite a loose mixture of an initiating charge, then to a transfer charge, and finally an output.

In your case, the output of cast ETN is good, but the loose ETN as a transfer charge should be lightly pressed - just enough to keep it from flowing around in the det cap. The NHN as an initiator SHOULD be loose. The NHN isn’t meant to necessarily detonate, just deflagrate fast enough so that the lightly pressed ETN can detonate with ease.

If all three of the materials (cast ETN, pressed ETN, and NHN) are too compacted, the heat from the e-match won’t have enough surface area to interact with and fully initiate the NHN, since NHN is a relatively insensitive EM. If you used a very sensitive EM like C2N14, then it’d be fine, since there’d only need to be a small portion of C2N14 required to ignite to carry the detonation or deflagration forward. C2N14 is obviously too sensitive to use in caps though.

In industry, the initiating mix of Lead Styphnate and Antimony Trisulfide (next to a e-match or fuse) doesn’t necessarily detonate, it just deflagrates fast enough to set off the Lead Azide charge behind it.

[Edited on 27-2-2024 by dettoo456]
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[*] posted on 27-2-2024 at 18:19


Quote: Originally posted by dettoo456  
The e-match should ignite a loose mixture of an initiating charge, then to a transfer charge, and finally an output.

In your case, the output of cast ETN is good, but the loose ETN as a transfer charge should be lightly pressed - just enough to keep it from flowing around in the det cap. The NHN as an initiator SHOULD be loose. The NHN isn’t meant to necessarily detonate, just deflagrate fast enough so that the lightly pressed ETN can detonate with ease.

If all three of the materials (cast ETN, pressed ETN, and NHN) are too compacted, the heat from the e-match won’t have enough surface area to interact with and fully initiate the NHN, since NHN is a relatively insensitive EM. If you used a very sensitive EM like C2N14, then it’d be fine, since there’d only need to be a small portion of C2N14 required to ignite to carry the detonation or deflagration forward. C2N14 is obviously too sensitive to use in caps though.

In industry, the initiating mix of Lead Styphnate and Antimony Trisulfide (next to a e-match or fuse) doesn’t necessarily detonate, it just deflagrates fast enough to set off the Lead Azide charge behind it.

[Edited on 27-2-2024 by dettoo456]


I'm learning a lot today. I was always thinking that thinks need to be tightly packed and any looseness was a liability. I guess I was quite wrong. I am guessing now that that is the problem behind my caps. I was packing them in too tightly.

So what I will do next is melt-cast the ETN, and then make a mix as LL suggested of a 1:1 NHN/ETN (forgetting the NHN-chlorate composition) and then lightly pressing it on top before inserting my e-match and sealing it or crimping a pyrotechnic fuse in (I have some reliable waterproof fuses now). No more tightly packing the top layer?

Quote:
If you have metal cavity, you can use only hand pressing (cca 20Kg) for output segment of ETN. For example 0.3 g. And for starting segment is possible use powder 0.15 ETN + 0.15 NHN. As 2 powders together. Thus 1:1. Heterogenous mixture. And hand pressed on 2 Kg. Should by works. Reliability this design was confirmed repeatedly. If it will not works, is error in quality NHN.....:cool:


OK I reread your post and I am not sure if I caught on. You saying I should not melt-cast the bottom layer of the ETN and just use a tightly hand pressed bottom with a loosely pressed top?
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[*] posted on 27-2-2024 at 20:05


Yes, the top layer shouldn’t be tightly packed. It can be compressed but only lightly, or left uncompressed.

And the output charge doesn’t need to be cast ETN. Depending on the EM you are planning to use, and the energy provided by the transfer charge, the output can vary in density or composition. I am not aware of the density vs Vdet of ETN, but I believe it should fairly forgiving. For example, PETN used in det cord is very low density and high surface area, and it still provides a great blast wave - it only needs a good “kick” to fully detonate along its length.

Also PBXs can be used an an output, Viton/HMX or Viton/RDX is used very commonly with only PETN or a sufficient slapper to initiate.

ETN/NHN should provide more than enough energy as an initiating/transfer material from the fuse to the output of pressed ETN.
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[*] posted on 27-2-2024 at 23:35


ManyInterests.......The output segment does not need to be push to 20 Kg. It is enough to manually push 0.3g of ETN to 2 Kg. That is, to the same density as the starting (primary) segment. The described combination of 0.3g + 0.15g / 0.15g always worked. Initiation by the fuse or electrically. In metal cavity 6/8 mm. 50 mm.






[Edited on 28-2-2024 by Laboratory of Liptakov]




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[*] posted on 28-2-2024 at 08:49


What about plastic ETN for the output charge?
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[*] posted on 28-2-2024 at 09:47


An ETN PBX might be fully detonated if you have a sufficient charge of normal ETN to set it off. 450mg of detonating ETN should (in theory) be able to initiate >500mg of 95/5 ETN/Wax or any other 95/5 ETN mix.

I’d recommend blending wax (or a different inert compound like a stabilizer) into any ETN you make - simply to lower sensitivity. ETN can be mixed with guar gum, xanthan gum, or a compound like guaiacol to improve storage and handling stability. And such blends/mixtures can easily be used as det cap fills, PBXs, or stationary (cast) charges. The performance is only moderately affected.
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[*] posted on 28-2-2024 at 15:20


Quote: Originally posted by dettoo456  
Yes, the top layer shouldn’t be tightly packed. It can be compressed but only lightly, or left uncompressed.

And the output charge doesn’t need to be cast ETN. Depending on the EM you are planning to use, and the energy provided by the transfer charge, the output can vary in density or composition. I am not aware of the density vs Vdet of ETN, but I believe it should fairly forgiving. For example, PETN used in det cord is very low density and high surface area, and it still provides a great blast wave - it only needs a good “kick” to fully detonate along its length.

Also PBXs can be used an an output, Viton/HMX or Viton/RDX is used very commonly with only PETN or a sufficient slapper to initiate.

ETN/NHN should provide more than enough energy as an initiating/transfer material from the fuse to the output of pressed ETN.


Learning a lot of new energetic material like Viton and C2N14. But like I said, I think my main mistake was thinking I needed to press as hard as possible (which I did for more than the 2kg that LL recommended) which is probably the main culprit behind my caps not being as powerful as they should be.

Like I said, I want to make a several caps for my next test, and hopefully set them all off. and collect the metal plates. I hope that my theory of the cold ice warping the metal isn't true, because I want those neat holes to impress everyone! :D

Quote: Originally posted by Laboratory of Liptakov  
ManyInterests.......The output segment does not need to be push to 20 Kg. It is enough to manually push 0.3g of ETN to 2 Kg. That is, to the same density as the starting (primary) segment. The described combination of 0.3g + 0.15g / 0.15g always worked. Initiation by the fuse or electrically. In metal cavity 6/8 mm. 50 mm.
[Edited on 28-2-2024 by Laboratory of Liptakov]


I want to make 50mm caps (they're 7x8mm (ID OD) with 0.5g charges. Would a 0.5g of melt-cast ETN (I really like the density of that and I want a blasting cap on par with the commercial stuff) and 0.3g of 1:1 NHN:ETN ratio that is very lightly tamped (total charge 0.8g). I am hoping that the light tamping would also be sufficient to detonate the 0.5g melt-cast charge? That was my question previously.

[Edited on 28-2-2024 by ManyInterests]
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[*] posted on 29-2-2024 at 02:09


I think you should abandon the idea of melt casting the base charge for now. It is possible that it will give you more power if you get it to detonate fully, however, this is not a given. The critical diameter of a crystalline explosive is related to its grain size; the finer the grain the smaller the critical diameter. A melt cast charge has quite a large grain, so you may be increasing the critical diameter to where the diameter of the cap becomes a limiting factor. You can overdrive the base charge to make it detonate even below its critical diameter (it won't be able to sustain the detonation, but in a cap that is less important) with a strong enough intermediate charge (the powdered ETN). The VOD will still be lower than it could have been though.
It will take experimentation to definitively establish whether the effects described above, or the higher density wins out in the end, and this is why I think you should drop the melt casting idea until you have actually conducted a number of successful tests (meaning clean penetrations of the steel plates).
About the warping of the plates, you can rest assured that it is not temperature related. Not much heat is transferred to the witness plate, and even if you heat it with a blowtorch and drop it in the snow it won't warp very much.
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[*] posted on 29-2-2024 at 03:22


Alright. I'll give press the base charge nice and good and gently put the igniting charge above it.

I did a second recrystalization last of my new ETN supply, in methanol so it is a fine powder. I need to make more good NHN, and I will experiment to increase my yield with that (adding more dextrinated nickel nitrate solution until no more reacts. The excess nickel nitrate can be washed away). I got two weeks to prepare, so I got time.
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[*] posted on 29-2-2024 at 03:39


Mikrotek said all important. You finally leave the casting ETN.....:cool:



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[*] posted on 29-2-2024 at 05:03


Quote: Originally posted by Laboratory of Liptakov  
Mikrotek said all important. You finally leave the casting ETN.....:cool:


For now yes. I will leave it behind. But maybe make one just to see. But others I will pres the base charge as hard as I can and the other just gently tamp but not press.

Edit: I thought of something... What about plasticized charges? I can try to plasticize the ETN and/or the ETN:NHN mixture using rubber cement. What do you think?

[Edited on 29-2-2024 by ManyInterests]
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[*] posted on 29-2-2024 at 06:41


You definitely don’t want to plasticize the NHN - it would slow down the burn rate to much. It might work if you plasticized it and made it into grains like gunpowder, but I don’t see a point to that. You could plasticize the ETN base charge to aid with pressing it.



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[*] posted on 29-2-2024 at 07:42


Yea, plasticizing the output segment of the cap (with a minimal amount of binder) should be fine, but you shouldn’t mess with the transfer or initiating material much at all. You want to keep that portion as sensitive as possible without making it unsafe to handle.

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[*] posted on 29-2-2024 at 07:57


The minimal binder would be 9 or 10% given the plasticization I have seen... Or less but letting it cure in the cap before adding anything else, since if I use 4 or 5% binder (rubber cement and bar and chain oil in my case) it'll harden and be inflexible once it fully dries.

At any rate. I think with the smaller charges I might not need to take a long trip... If I pull out my old 5 gallon bucket (filled with fire proof cleaning saw dust) it might work just as fine to muffle the sound, as long as I do it during the day time and have other noise going on.
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[*] posted on 29-2-2024 at 08:53


I once tested a 1g ETN detonator by drilling a hole in a chunk of lead just big enough for it to fit. I placed a five-gallon bucket over top it and the explosion was so quiet I first thought it had failed to properly detonate. It also captured all the shrapnel and is a great way to compare different detonators.

Here’s what the cut apart block looks like.

IMG_0314.jpeg - 1.5MB
For indoor testing, this method is probably the safest. You can also just melt the lead and use it again.




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[*] posted on 29-2-2024 at 08:54


Indeed, the sawdust bucket is an excellent way to iron out any problems with the caps before using them for anything bigger. Also for doing all the experimentation you are itching to do with a quick turnover between iterations.
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