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pjig
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The arrow shafts tend to be larger dia. This is better for a couple reasons . The alloy is harder aluminum, the dia allows electric match to fit in
the hole, and the charge is able to pack lower in the tube allowing less length cap body needed. Skinny tubes fill up quickly.
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UndermineBriarEverglade
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Quote: Originally posted by UndermineBriarEverglade  | | Yeah terribly low density. The small (rapid pour) acetone-formed crystals are very fluffy even when pressed hard. 500mg sounds good, I will melt cast
a thin layer and then crumble it up to make the output segment. |
450mg ETN output segment: melt-cast, then crumbled to fit into cap, then pressed. 11.55mm height x 6mm inner diameter tube = 1.38 g/cm3
50mg loose crystals on top for EBW
Setup of cap on the 1mm plate was the same as before. The hole from the bottom of the cap is not much larger than before. But a large hole was created at the side. Looks like the plate was
pulled apart. Popped the lid off my bucket of cat litter!
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ManyInterests
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https://youtu.be/2hT9GQ74Rnk
So I just watched this video and it answered quite a lot of inquiries I had about detonators, and It really got me thinking about a lot of stuff. Like
with regards to e-matches, he uses professionally made ones, but the examples of his homemade stuff just seem lack luster. With my NHN I use a
nichrome wire that is over a safety match to provide a fairly decent flame that I do believe has been sufficient to set off my detonators, so I will
continue to use it as is.
But what he did mention about things like reinforced detonators, which is a term I heard before but was unsure as to how it looked like. I also did
see how he used an arbor press to REALLY press his ETN hard into the cap.
I will never do that and I will stick to hand pressing as I always did, but it did make me think. Since he used multi-stage pressing, with the bottom
most layer being the most hard pressed, with the 2nd half more lightly pressed, and maybe topped off with a more tamped amount of ETN before the
tamped primary mixture.
I haven't loaded any of my detonators for the next test, since my next test is mostly about how bottomless (but taped) will fare vs. aluminum ball +
taped caps. I think that is a good thing to add to the experiment.
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Laboratory of Liptakov
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Small parts from output side of detonator show on full detonation ETN. Your EBW look reliable...... ...Good work
Development of primarily - secondary substances CHP (2015) Lithex (2022) Brightelite (2023) Nitrocelite and KC primer (2024)
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ManyInterests
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I thought of something. Since brisance is a very important part of the energetics used in detonators I wonder if I should try a new mixture.
According to Wikipedia a 50:50 mixture of melt-cast ETN and PETN by weight makes for an extremely brisant explosive, with a VoD of close to 9,000
meters per second. Since I do have some PETN (recystalized once) I want to try it out.
My one question is this: should I just mix the powders together or should I try to melt the ETN with the PETN? I saw one of Dugan Boomfax's videos
where this was done. I assume the latter would be better since it would mesh the two materials together better. But I have been wrong in the past.
What do you guys think?
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Sir_Gawain
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50/50? Shouldn't it be 66/34 ETN/PETN for oxygen balancing?
[Edited on 9-9-2024 by Sir_Gawain]
“Alchemy is trying to turn things yellow; chemistry is trying to avoid things turning yellow.” -Tom deP.
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ManyInterests
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I quoted wikipedia's article on ETN. As quoted below
| Quote: | | Mixtures of melt-cast ETN with PETN (about 50:50% by weight) are about the most brisant explosives that can be produced by moderately equipped
amateurs. These mixtures have Pcj slightly above 300 kbar and detonation velocity above 8 km/s. This is close to the maximum of fielded military
explosives like LX-10 or EDC-29 (about 370 kbar and close to 9 km/s) |
I did notice that there are no citations for this statement. I also reviewed Dugan Boomfax's video on ETN where he does cite a 65:35 ratio of ETN ETN and he DOES melt-cast them together and grind them up afterward. In this
situation I believe you are correct. A greater ratio of ETN would be more desirable in this case.
So this is what I will do. I will melt-cast ETN and PETN together in that ratio and grind up as finely as I can (with all safety considerations
obviously...) and I will use that to load up my blasting caps for my next test.
And for the loading, I will load up the first 50% of the cap with hard hand pressing before more lightly pressing the rest. Gotta get that explosive
train going!
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UndermineBriarEverglade
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ManyInterests, if you are making 10 caps at a time I would actually recommend NOT to use melt-cast ETN. In August I made some ETN, neutralized with
baking soda, recrystallized several times with acetone, and crashed into urea solution. I stored melt-cast fragments to use for output stages and
fluffy crystals to use for initiation, both at room temperature. Recently the melt-cast fragments began to decompose and release significant red NO2.
Thankfully I caught it in time. The original crystals haven't decomposed at all. I think that heating accelerated decomposition. Scary to think of 10
confined ETN samples fuming where you can't see them.
[Edited on 2024-10-3 by UndermineBriarEverglade]
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ManyInterests
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OK... so my trip was informative, but also kinda disappointing.
I actually made... 20 detonators! Yeah, I was going really hardcore with this and I was hoping to get enough information to say that I know how to
make a good detonator and call it a day. But I had some surprises.
I made detonators using aluminum bodies (6063 aluminum alloy), 5.56x45mm shell casings and 7.62x39mm shell casings, and 304 steel tubes with the ends
cut off.
For the brass bodies, I had pushed out the spent primer and drilled as wide a hole as I could in the bottom and loaded it to go from the hardest point
to the mouth. Thus learning from my previous mistake of thinking that I can just load it from the top and call it a day.
I made two variants of all my caps. Half had aluminum foil plugs (very thin 0.5-1mm plugs at the most) and then added a little tape to waterproof it,
and the other half only had tape at the end to waterproof it and prevent any energetics from crumbling out.
I loaded the caps as follows: First half the melt-cast ETN was loaded and pressed as hard as I could by hand, followed by the second half with decent
pressing but not as hard as the first. Then around 0.32g of 1:1 melt-cast ETN:NHN mix primary was added on top and only gently tamped without any
strong pressing (less than 1kg pressure). For 12 of the caps, I used around 1.14g of ETN in the caps.
6 caps (2 aluminum, 2 steel, and 2 brass, again with half having foil and the other half only tape) were loaded with 1.05g of 65:35 ETN/PETN melt-cast
together. The primary loading is the same as above
I also made 2 100mm caps that had around 3.25g of melt-cast ETN and 0.4g of the same primary mixture. These were extremely powerful and practically
obliterated large parts of the witness plate.
So I only posted pictures of the steel caps. Because one thing that I found is that the aluminum caps did not appear to have any effect on the witness
plate. In fact, it was almost like I was using my old plastic cap bodies for them. The brass caps also didn't perform well at all, merely bending the
side of the fence bracket (that is what I am using for a witness plate). This was the case across the board for all the energetic materials I was
using, whether it is ETN or ETN: PETN mix.
The steel caps, however, performed excellently. As LL says, he uses thicker steel bodies than I do, but mostly bottomless, and he has produced great
results.
The bottomless steel caps with ETN did better than the ones with aluminum plugs. The ones with the PETN loading did almost equally as well regardless
of the aluminum plug or just tape.
However there is the question as to why the others failed to fully detonate. I watched Dugan Boomfax's video on detonators and one thing that he did
mention that when the output fails to fully detonate it means that there could have been insufficient primary to set it off, or that it does need to
be pressed more (the primary that is).
Or the alternative is that the NHN is simply not as good of an initiating agent as I thought. While it with a steel body it appears to be good enough,
I am wondering if I should experiment with other primaries, like iNAP. I am very accustomed to working with the fairly safe NHN, but I think iNAP can
be made safe to work with, especially if it is loaded as gently and tamped as gently as I do with the NHN.
    
[Edited on 13-10-2024 by ManyInterests]
[Edited on 13-10-2024 by ManyInterests]
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Sir_Gawain
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I think your problem might be with the ETN/NHN mixture. I’ve used pure NHN with great success (~200mg per detonator). I think the ETN just slows
down the burn rate, preventing it from undergoing DDT.
“Alchemy is trying to turn things yellow; chemistry is trying to avoid things turning yellow.” -Tom deP.
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ManyInterests
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| Quote: Originally posted by Sir_Gawain | | I think your problem might be with the ETN/NHN mixture. I’ve used pure NHN with great success (~200mg per detonator). I think the ETN just slows
down the burn rate, preventing it from undergoing DDT. |
Yes, I will revert to using only NHN and not the mixture that LL recommended.
BTW, there is an earlier thread of a spiked NHN with sodium chlorate that the maker said was very effective, what do you think of that?
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ManyInterests
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Actually on second thought, I think LL's mixture is fine, Or maybe make caps with one pure nhn and the other mix to have a direct comparison. I just
need a more robust primary for the other cap types. I will try uNAP and see if it is able to make stuff in plastic or aluminum bodies go off.
One other thing I would want to do is to load brass caps from the top, as I did previously, but obviously have the bottoms fully drilled out as wide
as I can and just tape added. This is because looking at the latest stuff it seems like like the older ones with thr ends still on did better... it
makes me wonder how the bottomless ones would perform.
I will make another eight caps (four steel and four brass) for testing. Moderate pressing on all the ETN, with half having 0.3g of pure nhn and the
other around the same of an nhn etn mix.
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