Sciencemadness Discussion Board - Det Cap Strategies - Powered by XMB 1.9.11 (Debug Mode)

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]

Microtek - 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.

ManyInterests - 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]

B(a)P - 27-2-2024 at 11:48

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.

Laboratory of Liptakov - 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:

ManyInterests - 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.

ManyInterests - 27-2-2024 at 13:55

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]

dettoo456 - 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]

ManyInterests - 27-2-2024 at 18:19

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:

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?

dettoo456 - 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.

Laboratory of Liptakov - 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]

fx-991ex - 28-2-2024 at 08:49

What about plastic ETN for the output charge?

dettoo456 - 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.

ManyInterests - 28-2-2024 at 15:20

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!

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]

Microtek - 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.

ManyInterests - 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.

Laboratory of Liptakov - 29-2-2024 at 03:39

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

ManyInterests - 29-2-2024 at 05:03

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]

Sir_Gawain - 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.

dettoo456 - 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.

ManyInterests - 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.

Sir_Gawain - 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.

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

Microtek - 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.

ManyInterests - 29-2-2024 at 09:31

Quote: Originally posted by Microtek

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.

This is true. Especially for the 0.5-0.9g loads. Anything bigger might blow the bucket open. I need to weigh down the lid to contain it. To stop it from flying off and spreading too much stuff. Also putting it on a platform to catch the plate as it is pushed down is also good.

Anything bigger than what would be a no. 8 blasting cap needs to be done in field. Those run a.major risk of blowing my bucket apart.

The reason why I still have detonator issue is simply due to lack of opportunities to try them. Otherwise I would have figured it all out ages ago.

Microtek - 1-3-2024 at 00:30

Yes, I was talking about experiments with caps or similar sizes. The thing with HEs is that they also work on a very small scale, unlike LEs.
My point was that using the sawdust bucket you can test your cap design and tweak until you find something that works well in the plate penetration test for multiple repetitions. Then you can bring that design to your testing site and be confident that the cap is not what is holding back your test.

Laboratory of Liptakov - 1-3-2024 at 08:30

If you use wet sawdust, 2 short boards and a brick on the boards will serve (and will be enough) as a lid..... :cool:

ManyInterests - 5-3-2024 at 18:21

I just saw a new video by Dug on ETN (https://youtu.be/nayL7P1TztA) and I did have some questions about melt-cast ETN.

While I did melt-cast ETN (sometimes even superheating microgram sizes and saw them pop quite loudly), and I did have an incident where I accidentally melt-cast ETN in hot water (and ended up recrystalizing the result to get it out of there!). I was curious that if melt-cast ETN that has been ground back up and mixed is more difficult to detonate than it is previously or what?

Remember I melt-cast ETN in the blasting cap body that I wanted to use (both plastic and 304 stainless steel) and let it cool back down to room temperature. Is that the same or what? I am just asking here.

In making more NHN. It won't be necessary for my next test caps since I have 3.29g left from the supply I made two years ago. Plenty to make the 1:1 mix. But I already made plenty of hydrazine sulfate in order to make for the future (and I hope I won't need to make hydrazine sulfate again for the next few years, too).

Laboratory of Liptakov - 9-3-2024 at 07:55

Video is basically professional guide. Final pressing assemble is best what I saw ever. Thick wooden holder and the brick against wooden chips. Very easy, quickly, smart, cheap. ETN grain (melting - crushing) has best properties for filling to cavity. Time 36:35.
And has very good sesitivity (grain 1x1 mm) for mixture ETN 50 + NHN 50% used as primary mixture..... :cool:

One from best video on ETN theme ever.

ManyInterests - 10-3-2024 at 19:44

Video is basically professional guide. Final pressing assemble is best what I saw ever. Thick wooden holder and the brick against wooden chips. Very easy, quickly, smart, cheap. ETN grain (melting - crushing) has best properties for filling to cavity. Time 36:35.
And has very good sesitivity (grain 1x1 mm) for mixture ETN 50 + NHN 50% used as primary mixture..... :cool:

One from best video on ETN theme ever.

You could have told me that before hand!

I could have melt-cast the ETN and crushed them before putting in my cap.

Previously what I would do is to put the ETN in the cap, put the cap in hot water to melt-cast. Is that as good a technique? I was also thinking that if I was going to make a charge, would melt-casting in the container (with a dowel put in for a detonator well) be also the way it would go? Or would it be better to just melt-cast the ETN previously, break it up, and put it the charge?

Anyway, I made 5 caps for testing. I put in 0.61g of powdered ETN and I pressed them in as hard as I could into the cap. I then topped them with 0.3g of 1:1 ratio ETN/NHN as we spoke about before.

I learned some new stuff, like when putting them in, by tapping the outside of the cap I can cause the mixture to all settle nicely. I did not hard press it, I simply tamped it slightly with no pressing. Not even 1kg of pressure. I hope this will allow it to fully detonate.

Laboratory of Liptakov - 10-3-2024 at 23:27

For mixture 1:1 is tapping not good idea. Because fine powder NHN fall down. Mixture will apparted partially. Also tapping for mixture 1:1 increase density before hand pressing, which is contraproductive. Mixture must be sligtly pressed in one step but with bigger air gaps. Best is pour, shaking and push 1Kg. For same reaseon for bigger air gaps is better using grain ETN and not fine powder ETN. This is not crucial condition, but can increase reliability.
It is an insight from the study of the Nobel laboratories in the development of NPED.

[Edited on 11-3-2024 by Laboratory of Liptakov]

ManyInterests - 11-3-2024 at 08:10

For mixture 1:1 is tapping not good idea. Because fine powder NHN fall down. Mixture will apparted partially. Also tapping for mixture 1:1 increase density before hand pressing, which is contraproductive. Mixture must be sligtly pressed in one step but with bigger air gaps. Best is pour, shaking and push 1Kg. For same reaseon for bigger air gaps is better using grain ETN and not fine powder ETN. This is not crucial condition, but can increase reliability.
It is an insight from the study of the Nobel laboratories in the development of NPED.

[Edited on 11-3-2024 by Laboratory of Liptakov]

understood about the tapping. At any rate, when I added the finely powdered NHN (it is dextrinated) to the mostly powered ETN, but it had a slight chunk. I ground up the mixture some more and moved it around to fold them into each other. I believe it is a decently homogeneous mixture.

I did tamp, but it was very gentle, not even 1kg. I think it should have enough loose gaps between it to allow it to go off entirely. When I inserted the e-match it probably pressed a little more, too, but I don't think it was that much. I added enough tape around the match to make a nice fit into the cap, and to not allow the epoxy to seep into the sides and cause problems with the mixture. That is what caused the UXO cap for the previous test.

I'm going to glue these caps to the metal plates so I can just up and go when I need to test them out.

Quote: Originally posted by katyushaslab

Pressing at every addition is what I would recommend, that way you get better control of the densities of different regions. Having a high density "output side" of secondary is good, but you want a lower density region between it and the primary to ensure a good transition, if that makes sense.

I just dug this up from earlier in the thread. I should have written that down.

[Edited on 11-3-2024 by ManyInterests]

ManyInterests - 16-3-2024 at 17:15

Posting the results of my latest trip.

I will write my comments on the 2nd post. I got a lot of pictures to share.

ManyInterests - 16-3-2024 at 17:32

So this test was a far bigger success that before. I am quite happy with what is going on here. While I understand that clean holes are a good sign, I am not sure if that can happen with these plates. This is because I am resting it on a part of the metal, and as the explosion goes down, it will take that part with it. I suppose finding a straight piece of metal to do that on would help, but I am seeing serious damage here...

all the detonators used 0.6g of hand pressed ETN (Pressed as tightly as I could) and 0.3g of 1:1 ETN/NHN mix that is only tamped down gently.

Sir_Gawain - 16-3-2024 at 19:30

That looks great!
As I mentioned earlier, you need to get some lead blocks to test with. It gives much better comparison than holes in a steel plate. You can easily get large amounts of lead from firing ranges. Also, tire shops will sometimes give you used wheel balancing weights.

OneEyedPyro - 17-3-2024 at 01:18

So this test was a far bigger success that before. I am quite happy with what is going on here. While I understand that clean holes are a good sign, I am not sure if that can happen with these plates. This is because I am resting it on a part of the metal, and as the explosion goes down, it will take that part with it. I suppose finding a straight piece of metal to do that on would help, but I am seeing serious damage here...

all the detonators used 0.6g of hand pressed ETN (Pressed as tightly as I could) and 0.3g of 1:1 ETN/NHN mix that is only tamped down gently.

Those are framing mounts/braces for 2X4 boards, I assume? Not bad results at all for hand pressed considering how sturdy those braces are. To give the best idea of performance you should use a larger piece of a weaker, more ductile material like a lead plate as Gawain said. Consider buying a couple boxes of shotgun shells to melt into a block, two boxes of cheap 12 gauge shells only costs $15 yielding about three pounds of lead and roughly 50 grams of DBSP.

This is assuming you live somewhere like the US.

ManyInterests - 17-3-2024 at 06:23

Quote: Originally posted by OneEyedPyro

I am in Canada, however this won't be a problem. I have an RPAL (restricted possession and acquisition license), meaning I can legally obtain shotgun shells if I need to. I actually do own a shotgun so it do get shells for target shooting. I use only slugs because the range does not allow buckshot.

However an easier alternative does exist here: https://shorturl.at/wzAER

Same price as you mentioned, at least 3lbs, and all available without any huss or fuss.

I think I want to see if I can put in 1g of melt-cast ETN in the cap and set it off. I do have some questions about melt-cast ETN.

what I did previously (with both plastic and now metal cap bodies) is to press the ETN inside the cap body and then partially submerge the cap in 70C water (just enough for the part with the ETN to be surrounded by the water) and leave it for 7 minutes to allow for it to be completely molten, then CAREFULLY remove it and place it in the hole in a foam block that I made to support the cap, then let it stay for 30 minutes or so to make sure that everything has cooled down and solidified to room temperature.

But after seeing another video on the matter, I did see using small quantities of ETN on parchment paper over warm water (heated to 60C), and then breaking up the pieces after they fully cool and solidify.

LL mentioned that melt-cast ETN that has been ground back up into powder would make a superior mixture with NHN as boosted primary.

but my question is pressing said melt-cast powdered ETN into a detonator housing. Is it easier or harder to set off than ETN melt-cast within the body itself? Would it be superior as an output to press it or is melt-casting in-body sufficient?

Edit: What is DBSP?

[Edited on 17-3-2024 by ManyInterests]

fx-991ex - 17-3-2024 at 07:40

Lead for shotgun shell usually is hardened with antimony and sometime some tin, instead of buying shell and taking them apart you can buy buckshot lead for reloading.
But you can get muzzleloader pure lead ball

OneEyedPyro - 17-3-2024 at 08:36

Melt cast ETN that has been crushed will have a higher packing density and thus higher output than recrystallized powder when hand pressing but it will have a higher sensitivity to initiation than a solid melt cast.
In terms of energy density and VoD a solid melt cast will always be the most powerful.
Crushed up molten ETN gives good power, ease of detonation and is easy to handle since it flows smoothly when pouring whereas fluffy crystals do not.
A fine powder pressed to a moderate density should have higher sensitivity than crushed up cast ETN but that doesn't necessarily apply in the voodoo art of making reliable NPEDs.

DBSP is just short for double base smokeless powder. Shotgun powders tend to use less burn rate inhibitors and have more NG content. It's a respectably powerful HE in its own right and is certainly worth saving if you're going to scrap shotgun shells. The above post is correct though. Lead shot isn't pure, soft lead but it beats galvanized steel as a test medium for caps.

ManyInterests - 17-3-2024 at 16:08

Ahh I should have known. Making DBSP (for pistols mostly) is a goal of mine for the future. This is why I want to make a lot of very high quality high nitrogen NC to hopefully turn into home made power, using DEGDN as the energetic. But that is for another place and another time.

That being said, I will melt case some ETN (only 1g at a time and be VERY careful with it) and I will break it up not to load it within a cap, but to mix it with NHN as LL said that it is the superior initiating agent. I think with that it should have no issue initiating sold-cast ETN.

And once that is done... I hope to happy to say that I am able to make detonators on par with the real stuff.

Laboratory of Liptakov - 17-3-2024 at 23:35

I estimate, that steel plate is only 1mm of thickness. Is it slim plate. For 0.6g output ETN is necessary 3mm steel plate. Or 1/10 of inch. Therefore are results difficulty read. On this weak plate.
For 0.3 - 0.4 g ETN is best 2 mm steel plate. At inner diameter 7 mm.
Best is of course the Lead block. Is it cheapest solution ever. With exact results.
But I've been repeating this here for at least 1 year..... :cool:

ManyInterests - 18-3-2024 at 02:38

I estimate, that steel plate is only 1mm of thickness. Is it slim plate. For 0.6g output ETN is necessary 3mm steel plate. Or 1/10 of inch. Therefore are results difficulty read. On this weak plate.
For 0.3 - 0.4 g ETN is best 2 mm steel plate. At inner diameter 7 mm.
Best is of course the Lead block. Is it cheapest solution ever. With exact results.
But I've been repeating this here for at least 1 year..... :cool:

OK, I will get some lead and melt it with my blowtorch to make blocks.

I want to use the melt-cast ETN to mix with NHN and try to set off solid-cast ETN. Since melt-cast ETN doesn't take up a lot of space, I think I can fit a full 1g within a 50mm cap.

How big of a lead block do I need? Would a cupcake mold work? I have a small crucible that I will post pics of. I saw this video as a guide (https://youtu.be/AmAwEsB-ADs) I hope it will be easy to get the lead block out of the ceramic...

dettoo456 - 18-3-2024 at 11:36

I personally wouldn’t recommend the lead block method, simply because it’s unnecessarily toxic and the reproducibility can be variable (getting the dimensions and casting density of the lead accurate each time).

If you can find a piece of leaf spring steel, just cut a piece off (maybe 100x75x3mm), bend it straight, glue to a piece of thick wood, and use as a witness plate. You can stick the witness plate in a bucket and fill with vermiculite to get a decent testing apparatus.

With lead you’d be left with atomized bits all over the place and re-melting would be a headache.

OneEyedPyro - 18-3-2024 at 13:28

I personally wouldn’t recommend the lead block method, simply because it’s unnecessarily toxic and the reproducibility can be variable (getting the dimensions and casting density of the lead accurate each time).

If you can find a piece of leaf spring steel, just cut a piece off (maybe 100x75x3mm), bend it straight, glue to a piece of thick wood, and use as a witness plate. You can stick the witness plate in a bucket and fill with vermiculite to get a decent testing apparatus.

With lead you’d be left with atomized bits all over the place and re-melting would be a headache.

Shooting steel targets with a shotgun makes a huge cloud of lead dust, this is done hundreds if not thousands of times in a single day in competitive 3 gun shooting matches. You don't hear about anyone getting lead poisoning.

I think it's reasonable to go out of your way to avoid inhaling or ingesting lead but it's still the standard for testing EMs and it works extremely well. Steel is just too hard/tough to give a good picture as a witness plate.

ManyInterests - 18-3-2024 at 18:35

I want accurate results. My personally set goal is that I want to make a detonator that is on par with military or commercial detonators. So if I need to use lead blocks, I'll do it.

But remember, i will still be likely doing my tests outside. I found a nice secluded spot where I think I can do my tests without bothering anyone. Albeit I don't want any lead contamination where I am setting the stuff off. But then again, what I am doing is so small it is ultimately meaningless.

I looked at Sir_Gawain's lead block, based on the nickel he used as a comparison it is 70mm tall, but how thick?

Sir_Gawain - 18-3-2024 at 18:56

It’s actually a cylinder. It was cast in a regular soup can, so it’s about 7 cm in diameter. Also, you don’t have to test the detonator inside a lead block like I did. It’s probably easier to just use it in the same way as you did with the steel plate, then compare craters.

ManyInterests - 18-3-2024 at 19:28

Quote: Originally posted by Sir_Gawain

It’s actually a cylinder. It was cast in a regular soup can, so it’s about 7 cm in diameter. Also, you don’t have to test the detonator inside a lead block like I did. It’s probably easier to just use it in the same way as you did with the steel plate, then compare craters.

The test plate that I use is probably not the best. The reason why I use it is because that bend provides an easy place to tape it to without needing to construct a platform to stick it on. It is also very, VERY cheap. while some steel plates cost several dollars and some going for almost 10$ a piece. These little bits I use are barely 50 cents, and since I need a lot of them, I just don't want to waste too much money.

The bend doesn't allow for much single 'downward' hole, since the explosion will obviously blow that side piece apart in various unpredictable ways. It doesn't work best... but in all honest I have been seeing such progress (or at least I hope I have) that if it continues like this it'll be all good.

Edit: I can and use a hunt's tomato paste can then to make the cylinder. But I would need to make multiple them... not really sure if I feel I need to be that precise. I think the tests are going fine so far.

[Edited on 19-3-2024 by ManyInterests]

EF2000 - 19-3-2024 at 09:15

Edit: I can and use a hunt's tomato paste can then to make the cylinder. But I would need to make multiple them... not really sure if I feel I need to be that precise. I think the tests are going fine so far.
[Edited on 19-3-2024 by ManyInterests]

You don't need multiple lead blocks for multiple tests. You can cast a thick lead plate. Look at the picture at quoted post by our great genious Liptakov:

Lead block is pretty good compromise for comparative testing.

However during measurement, in same block, is necessary always create reference impact from known EM. As reference is here CHP.... :cool:

...LL

One lead block, enough place for multiple tests without remelting, easy comparison of craters.
And if one is too concerned with lead toxicity, they can always experiment with other soft metals and alloys, tin for example.

untrained professional - 7-4-2024 at 18:36

Are aluminum blocks good for testing I have many cast aluminum ingots on hand but I can also use mild steel that’s about 2.9 mm thick

B(a)P - 7-4-2024 at 20:34

Quote: Originally posted by untrained professional

Are aluminum blocks good for testing I have many cast aluminum ingots on hand but I can also use mild steel that’s about 2.9 mm thick

Aluminium is less desirable as you can get so many different types, so it is hard to make comparisons.
Mild steel is a consistent product so that would be the better choice.
Most importantly you want a material that is consistent. Lead is a desirable test medium as it has been used as a test medium for so long, you can compare your results with the results in literature. Lead is used preferentially as it is easy to shape and handle, soft, but not too soft.

Laboratory of Liptakov - 7-4-2024 at 22:17

Lead block has universal using. For example for blacksmith method creating copper cone. Source of metal, the weighing for models, Hess test of brisance, Trauzl test for working power of EM. Projectiles and etc. Every researcher must have at home minimal 5 Kg of Lead....

untrained professional - 14-4-2024 at 15:19

I’m curious if anyone knows how far commercial detonators penetrate mild steel like the no.6, no.8, M6, M7 and M100 or other countries versions. It would be useful knowledge to compare tests results to.

Nu0p - 17-4-2024 at 19:27

Sharing my first go at making a detonator.

Created 3 detonator caps using the 6x50mm cardboard tubes (bottle rocket tubes). Secondary is NQ mixed with 4% PTFE powder. Primary was NAP (native crystal morpology). The ends were sealed with scotch tape. Will eventually investigate plastidip. Tape did work well for keeping the powder in while loading and pressing. Pressed using 5.7mm HS steel rod and an arbor press. I didn’t work on good sealing, this is a very simple prototype.
- #1 was loaded with 750 mg NQ pressed to 1.0 g/cc and topped with 100 mg NAP.
- 75 mg NAP was pressed onto NQ, remaining 25 mg was loose and in contact with FF mix on the electronic match.
- #2 was loaded with 750 mg NQ pressed to 1.4 g/cc. Topped with 100 mg NAP.
- 50 mg NAP was pressed lightly into NQ, 50 mg loose in contact with FF mix on e-match.
- #3 was loaded with 750 mg NQ pressed to 1.4 g/cc. Topped with 100 mg NAP.
- 75mg pressed, 25 mg loose in contact with 5mm safety fuse.

I have metal casings but I wanted to make learn to use the cardboard. Hopefully it works. Hopefully the NQ detonates, not sure about that one yet. I intend to set these off on top of lead blocks. I expect about 5.5 KMS. Not the highest, but enough to evaluate.

ETN, PETN, and RDX are planned for testing as well when I get to it. Results to come. Stay tuned.

[Edited on 18-4-2024 by Nu0p]

MineMan - 17-4-2024 at 19:49

Quote: Originally posted by Nu0p

Sharing my first go at making a detonator.

Created 3 detonator caps using the 6x50mm cardboard tubes (bottle rocket tubes). Secondary is NQ mixed with 4% PTFE powder. Primary was NAP (native crystal morpology). The ends were sealed with scotch tape. Will eventually investigate plastidip. Tape did work well for keeping the powder in while loading and pressing. Pressed using 5.7mm HS steel rod and an arbor press. I didn’t work on good sealing, this is a very simple prototype.
- #1 was loaded with 750 mg NQ pressed to 1.0 g/cc and topped with 100 mg NAP.
- 75 mg NAP was pressed onto NQ, remaining 25 mg was loose and in contact with FF mix on the electronic match.
- #2 was loaded with 750 mg NQ pressed to 1.4 g/cc. Topped with 100 mg NAP.
- 50 mg NAP was pressed lightly into NQ, 50 mg loose in contact with FF mix on e-match.
- #3 was loaded with 750 mg NQ pressed to 1.4 g/cc. Topped with 100 mg NAP.
- 75mg pressed, 25 mg loose in contact with 5mm safety fuse.

I have metal casings but I wanted to make learn to use the cardboard. Hopefully it works. Hopefully the NQ detonates, not sure about that one yet. I intend to set these off on top of lead blocks.

ETN, PETN, and RDX are planned for testing as well when I get to it.

So… did it work?

Nu0p - 17-4-2024 at 20:05

I will find out tomorrow. Just sharing the set up right now.. I am excited and I thought that you all might appreciate it.

More to come…

Laboratory of Liptakov - 17-4-2024 at 22:12

Nu0p.....You mean nitroguanidine nitrate as secondary? It was tested your pure Nickel Aminoguanidine diperchlorate (NAP) against lead block? According all is NAP primarily - secondary EM. You not need NQ. My first choice should by testing of 300 mg high pressed NAP + 100 mg low pressed NAP in one paper cavity. And after sucessful this, is possible next step, testing very low sensitive NQ.
Only my opinion, not more.... :cool:

Here is MineMan sucessful nice test. Quality hole in 1,5 mm in steel from NAP at ID 4,5 mm only.

NAP dia4.5.jpg - 9kB

Nu0p - 18-4-2024 at 04:36

LL, I have detonated the NAP in small quantities, loosely confined, but not in a detonator body. I agree that the NQ is not needed as the NAP will serve as both the primary and secondary. I am using the NQ because at this point I feel more comfortable pressing it and the reagents are easier for me to come by in quantity. I also want to see if the NAP will successfully detonate the NQ. I see your point however and I will add an NAP detonator to the testing and get a good baseline.

underground - 18-4-2024 at 06:12

The problem with NQ is that it can not be pressed in high density. Does the PTFE help to press it in higher densities ? Also it in very insestitive. A mixture of ETN/NQ or AP/NQ would be better.

[Edited on 18-4-2024 by underground]

dettoo456 - 18-4-2024 at 08:14

Sensitized NQ would be a good output charge but it just has too low density to be practically useful. MeNQ or EtNQ would likely be better since their performance and sensitivity is similar to NQ, but they have higher density and can be melt cast at high temperatures if need be. The alkyl derivatives of NQ only require NQ & an alkyl amine to be refluxed whilst vacuuming off excess NH3 produced in the alkylation.

Another option could be (N-nitroguanyl)urea, if that is even isolatable. Dehydration of guanylurea nitrate or cyanation of nitroguanidine with potassium cyanate & acid might be possible routes.

underground - 18-4-2024 at 10:26

That is interesting. Nice observation. Calcium cyanate is very easy to make from urea and CaOH. I believe dinitroguanylurea would be interesting too, or salts of nitroguanylurea. Calcium cyanate is a lot easier to produce than methylamine

Guanidine nitrate actually can be reacted with calcium cyanate to produce guanylurea nitrate, then H2SO4 to nitroguanylurea. Has this even been tried ?

[Edited on 18-4-2024 by underground]

Nu0p - 18-4-2024 at 14:08

In all three cases the secondary failed to detonate.

I am quite pleased that the electronic matches worked well, however. I was able to reliably set off the charges over 100 feet of RG-174 using only a 9 volt alkaline battery. I didn’t like the delay at that voltage, however, and I will be increasing it to 18 volts for the next cycle.

Two things made the NQ easier to press. I did a wet grind in water and dried to get powdered NQ at 0.735 g/cc. This powder was then blended with the PTFE which reduces friction while pressing and acts as a binder. I know that I could take it above 1.4 g/cc as I didn’t have to press very hard to get there.

I’m currently curious about PrNQ, and EtNQ. I’d like to see what happens at higher densities, and if I press the NAP harder against the secondary. I’m also interested in LL’s suggestion. Photos attached. I have a thick plastic planter which is set down into a hole in my woods, then covered with another planter. It deadens the noise quite a lot.

dettoo456 - 18-4-2024 at 14:42

The NQ is probably just too insensitive - most other primaries in the 100mg range likely wouldn’t be able to set it off either in the conditions you used. A metal case to aid in confinement may help to get the NQ going but I don’t think it’d be worth the trouble of making. PETN and RDX are the gold standard for output charges; 750mg of either is enough to get a train started fairly reliably.

PETN pressed lightly by hand w/ a hard plastic rod should achieve a plenty high VoD, especially since it’s VoD isn’t very density dependent.

Small, cast boosters of alkyl-NQ mixed with NQ could be interesting seeing as NQ is already so cheap and a little <10g booster should be able to reliable set off secondaries & tertiaries like ANSU.

And you should look into getting a legit electric blasting machine - either by building one from a flash capacitor circuit or buying a used one for a couple hundred $. UXO, especially from sending stray 9V current into it, is no joke and isn’t worth losing a finger, eye, or hand from. Or just use good old time fuse.

Nu0p - 18-4-2024 at 15:08

And you should look into getting a legit electric blasting machine - either by building one from a flash capacitor circuit or buying a used one for a couple hundred $. UXO, especially from sending stray 9V current into it, is no joke and isn’t worth losing a finger, eye, or hand from. Or just use good old time fuse.

Does anyone have a lead on one? A few hundred $ I can swing, but a few thousand is not in the cards at the moment. I’ll also look into building one.

Nu0p - 18-4-2024 at 17:07

Alright, I did another run. This time I used as LL suggested and pressed 300 mg NAP to 1.7 g/cc, then topped it off with 100 mg loose fill in contact with a good old fashioned fuse until I can get my hands on the proper equipment. There was no deformation at all in the lead block. Perhaps I need a metal casing for this?

Perhaps my math is wrong? With a 5.7mm diameter I calculated that I would need to press 300 mg down to a height of 6.91 mm to achieve 1.7 g/cc

[Edited on 19-4-2024 by Nu0p]

dettoo456 - 18-4-2024 at 19:47

The 1.7g/ml is correct, though it could’ve been dead-pressed. I don’t personally know if NAP can or cannot even be dead-pressed, someone else with more handling experience might.

As for blasting machines, if you’re in the US, just look on eBay, Facebook marketplace, Etsy, Craigslist (I found a super expensive sequential machine for dirt cheap there), etc. Research Energy Ohio makes somewhat decent ones that take 9V batteries, scorpion too I think. Blasterstool.com also has their own brand of one for somewhat cheap but you’ll need to fill out a use form and submit your SSID - take that as you may. I’d be interested in building one too, I think a flash capacitor circuit from a disposable camera, with high voltage switches to make it safer, and epoxied into a strong nylon case would be the cheapest option. Those flash capacitors can deal out more V than lots of commercial blasting machines too, and they only need a 9V or 2 AAs in most cases. They’re dirt cheap too.

[Edited on 19-4-2024 by dettoo456]

Nu0p - 18-4-2024 at 19:47

Small, cast boosters of alkyl-NQ mixed with NQ could be interesting seeing as NQ is already so cheap and a little <10g booster should be able to reliable set off secondaries & tertiaries like ANSU.

I’m going to look into PrNQ. Propylamine is hard to come by but not impossible. I’ve read that there are valid routes using Propyl Iodide as well. How much ETN would I need to add to the melt cast PrNQ to sensitize it in order to make a booster? 10% by mass?

dettoo456 - 18-4-2024 at 19:58

You’d be better off just buying the propylamine IMO, Sigma sometimes has sales on their less popular reagents, and they had it for around $40/L last year I believe. 10-30% ETN sounds reasonable, but mixing melt cast ETN with other EMs can cause issues due to weird hydrolysis pathways and partial reduction of nitro groups on nitramines like NQ. An alkyl NQ with a metal fuel such as Mg/Al, Al, or Mg may be sensitive enough to perform, though careful heating of that sort of mix would be cause for concern.

Nu0p - 18-4-2024 at 20:12

An alkyl NQ with a metal fuel such as Mg/Al, Al, or Mg may be sensitive enough to perform, though careful heating of that sort of mix would be cause for concern.

Did you intend to say that it would not be cause for concern?

Etanol - 18-4-2024 at 21:44

Verify the critical diameter of NQ at your density with power booster.
I think it is problem.

How is formula of PrNQ and EtNQ? Are you sure that it is able to detonation with such bad oxygen ballance?

dettoo456 - 19-4-2024 at 04:45

Quote: Originally posted by Nu0p

An alkyl NQ with a metal fuel such as Mg/Al, Al, or Mg may be sensitive enough to perform, though careful heating of that sort of mix would be cause for concern.

Did you intend to say that it would not be cause for concern?

Yes, melting organic mixtures of reducing agents can be dangerous. Mg or Al may try to reduce the Nitramine, and cause an exotherm that’d need to be controlled for.

And Etanol is right about the critical diameter, it just may be too small of a charge. As for OB% for the Alkyl NQs, they are obviously lower, but I wouldn’t think their VODs would be much lower than say 6000m/s. I can’t quote anything at the moment though. There might be some patent or report of PrNQ from BAE Systems out there stating its properties; BAE apparently looked into it as a legitimate material for production a while back.

dettoo456 - 19-4-2024 at 05:44

https://apps.dtic.mil/sti/pdfs/AD1063959.pdf

https://ndiastorage.blob.core.usgovcloudapi.net/ndia/2013/IM...

Nu0p - 19-4-2024 at 06:46

The 1.7g/ml is correct, though it could’ve been dead-pressed. I don’t personally know if NAP can or cannot even be dead-pressed, someone else with more handling experience might.
…
I’d be interested in building one too, I think a flash capacitor circuit from a disposable camera, with high voltage switches to make it safer, and epoxied into a strong nylon case would be the cheapest option. Those flash capacitors can deal out more V than lots of commercial blasting machines too, and they only need a 9V or 2 AAs in most cases. They’re dirt cheap too.

[Edited on 19-4-2024 by dettoo456]

There is not a lot of public literature on this, but anecdotally NAP is capable of being pressed to 2 g/cc and beyond. 1.7 should not have dead pressed it. Maybe it wasn’t in good enough contact with the block. I’m going to try again, because that result really surprised me.

Regarding the detonation machine, I’ll look into this. I can find one rather inexpensively but with my skillset I could benefit the community by engineering one and writing it up. In the absence of a flash circuit, All you’d really need is a high voltage capacitor, a buck/boost converter, some high voltage switches and a few terminals. Perhaps an LED to alert you to when it is at the target voltage. All of this is available through sources like Amazon or EBay.

Thanks for the source material!

[Edited on 19-4-2024 by Nu0p]

Nu0p - 19-4-2024 at 07:22

Quote: Originally posted by Etanol

Verify the critical diameter of NQ at your density with power booster.
I think it is problem.

How is formula of PrNQ and EtNQ? Are you sure that it is able to detonation with such bad oxygen ballance?

What I understand about the critical diameter for NQ is limited. These things are new to me. I’ve been told that it is at minimum 14mm, so when I pressed it I targeted 14mm as pressing depth. I suspect that you are correct and a 6 mm diameter cylinder that is 14mm long may just not be enough material.

Is there better source material available on NQ that shows critical diameter as a function of density?

B(a)P - 19-4-2024 at 14:48