Sciencemadness Discussion Board - Det Cap Strategies

I have some questions about caps using CHP. I know you said that CHP works well alone and doesn't need ETN or PETN as a booster. But how much do you put in a cap? Do you hand press? How much and how hard? Does CHP melt cast? What is the loading density you recommend? I know you've used metal cap bodies, but I will experiment with my bic round stics.

[Edited on 24-8-2022 by ManyInterests]

I think you will find most of your answers on the first page of this thread.

https://www.sciencemadness.org/whisper/viewthread.php?tid=158259

Laboratory of Liptakov - 24-8-2022 at 04:47

CHP require solid metal cavity for full DDT. If you change the cavity for plastic or some else, CHP will not works. Others parameters and setting are described by thread LL8.

ManyInterests - 24-8-2022 at 12:53

CHP require solid metal cavity for full DDT. If you change the cavity for plastic or some else, CHP will not works. Others parameters and setting are described by thread LL8.

I'll review it. But that is duly noted. When I make do CHP ones I will use tubes such as these: https://bit.ly/3TenykA

karolus28 - 24-8-2022 at 13:08

I'll review it. But that is duly noted. When I make do CHP ones I will use tubes such as these: https://bit.ly/3TenykA

the link shows me a 404, could you post another one?

B(a)P - 24-8-2022 at 15:03

Quote: Originally posted by karolus28

I'll review it. But that is duly noted. When I make do CHP ones I will use tubes such as these: https://bit.ly/3TenykA

the link shows me a 404, could you post another one?

These work well when brass is compatible with your composition/s.
They are widely available in hobby stores.
https://www.hobbytools.com.au/brass-rnd-tube-5mm-od-x-44mm-wall-x-300mm-12-3pc/
BRASS ROUND TUBE 5mm OD x .44mm Wall

ManyInterests - 24-8-2022 at 15:08

Bleh, I hate it when it does that. I won't post a link since those always get screwed up, I'll post the search term:

5 pieces OD 6mm OD 7mm OD 8mm SS304 One End Round head Closed Stainless Steel Thermowell Thermocouple Protection pipe L30-500mm

Search for that on aliexpress.com, it should be the first to come up.

[Edited on 24-8-2022 by ManyInterests]

ManyInterests - 30-8-2022 at 21:53

My previous post didn't make it due to file size...

So it's been nearly 20 days since I made the cap. Is it just me, or is there some very, very slight yellowing happening on some small portion of the ETN. I think this has to do with the fact that there is a hair that made it into the cap by accident.

At any rate, I don't think it'll do much to hinder the cap's performance it is very paint and only affects a very small part. The melt-cast ETN is completely intact. I think it is the hair that's doing it.

MineMan - 31-8-2022 at 02:19

My previous post didn't make it due to file size...

So it's been nearly 20 days since I made the cap. Is it just me, or is there some very, very slight yellowing happening on some small portion of the ETN. I think this has to do with the fact that there is a hair that made it into the cap by accident.

At any rate, I don't think it'll do much to hinder the cap's performance it is very paint and only affects a very small part. The melt-cast ETN is completely intact. I think it is the hair that's doing it.

Your over thinking this. PETN, and nickel AG perchlorate. In plastic so no shrapnel. No need for melt cast. It’s a cap. Perfect is always the enemy of good

OneEyedPyro - 31-8-2022 at 04:22

ETN always gets a bit off white when cast due to heat decomposition.
Assuming you properly neutralized it you won't see any further changes.

As far as the hair goes, it tells me that you are possibly being a bit sloppy and careless. A hair isn't going to cause decomposition.

Remember that this hobby is very unforgiving, there's no time to react when things go wrong.

It's usually that 1% that will bite you and the other 99% that didn't which makes you complacent enough to get bit in the first place.

ManyInterests - 1-9-2022 at 18:27

I am extremely aware that it only takes one mistake to fuck your life up (or end it). The only error I made in construction here is the fact that there is a hair in there. Everything else went almost perfect.

For future caps I can make the design smoother and cleaner.

If that is the case with the slight yellowing, then I guess I am good! A working blasting cap that I should test at the earliest opportunity.

And I am very confident that all acid has been neutralized, even before I recrystalized the ETN. I washed the ETN numerous times with water until I tested the pH as neutral, then I washed them again several more times for good measure. Then I recrystalized them after they fully dried and washed them some more. I'll be a monkey's uncle if there's any acid left.

Last time I am confident that I didn't fully neutralize the acid, which is why it turned a sawdust brown. This is not happening now, which is a good thing. Also the melt-cast ETN has not changed at all, only the loose powder seems to have a very mild change. The NHN is also completely intact.

XeonTheMGPony - 15-9-2022 at 03:26

I am extremely aware that it only takes one mistake to fuck your life up (or end it). The only error I made in construction here is the fact that there is a hair in there. Everything else went almost perfect.

For future caps I can make the design smoother and cleaner.

If that is the case with the slight yellowing, then I guess I am good! A working blasting cap that I should test at the earliest opportunity.

And I am very confident that all acid has been neutralized, even before I recrystalized the ETN. I washed the ETN numerous times with water until I tested the pH as neutral, then I washed them again several more times for good measure. Then I recrystalized them after they fully dried and washed them some more. I'll be a monkey's uncle if there's any acid left.

Last time I am confident that I didn't fully neutralize the acid, which is why it turned a sawdust brown. This is not happening now, which is a good thing. Also the melt-cast ETN has not changed at all, only the loose powder seems to have a very mild change. The NHN is also completely intact.

add tiny amount of urea during the recrystalization, the scavenger helps.

ManyInterests - 15-9-2022 at 18:49

I will re-recrystalize it then. There's no rule saying you can't do that.

I noticed a very strange thing... there was a net weight GAIN after the recrystalization. I never saw that happen before.

Edit: I also found a tube cutter at a local thrift store. I should be able to cut my own tubes now instead of buying premade ones. I saw LL flatten one end partially and then cramming a small of aluminum foil into the other to completely seal it.

Still for my NHN and ETN caps I will continue to use plastic bodies for now.

[Edited on 16-9-2022 by ManyInterests]

Microtek - 19-9-2022 at 04:10

If recrystallization results in mass gain, then you probably have entrapped solvent in your crystals. Difficult to imagine any other explanation. On the bright side, it will diffuse out and evaporate over time if you keep the container open.

Herr Haber - 19-9-2022 at 08:35

If recrystallization results in mass gain, then you probably have entrapped solvent in your crystals.

Or NaHCO3 maybe ? I'm pretty sure that happened to me once.
Mhh, you've got me something to think about. Thanks.

ManyInterests - 19-9-2022 at 15:51

If recrystallization results in mass gain, then you probably have entrapped solvent in your crystals.

Or NaHCO3 maybe ? I'm pretty sure that happened to me once.
Mhh, you've got me something to think about. Thanks.

No bicarbonate was used. Neither in the original filtration nor in the recrystalization. Just a hell of a lot of water. I washed it out, diluted the water further and added baking soda to further remove the acid in the water before pouring it down the drain.

The recrystalization involved only hot acetone (an excess of acetone) and then I dumped it into 3.5 liters of ice cold water and filtered it out, and washed the ETN with more water still.

Since I forgot to put urea in the water. I will re-recrystalize in a few days just to make. You can't be too safe with this stuff. I will probably dispose of the ETN via burning in the next month or two. I really don't need that much ETN and it isn't a good idea to store that much anyway (for both safety and legal reasons).

XeonTheMGPony - 20-9-2022 at 03:36

try methanol for the recrystalization I add a bit to the methanol and to the water as my goal was to have it incorporated to the crystal structure as well when doing high density crystals I directly crashed out the ETN by cooling the Methanol under high stirring

ManyInterests - 20-9-2022 at 08:47

Quote: Originally posted by XeonTheMGPony

try methanol for the recrystalization I add a bit to the methanol and to the water as my goal was to have it incorporated to the crystal structure as well when doing high density crystals I directly crashed out the ETN by cooling the Methanol under high stirring

Add a bit to the methanol and to the water? What do you mean? You add methanol to the water in addition to urea?

Herr Haber - 20-9-2022 at 09:59

You could add a pinch of your favorite base to the water in your final recrystalization to neutralize the remaining acid that was freed from the crystals. Properly done and the product wont degrade for years: no smell, no weird colors.
All your steps before that seem ok to me. Excess of acetone compared to what you can see in the litterature seems normal. Anyway, it's that or looking at a molten blob of ETN in acetone so it's not a hard choice!
3.5 liters of water eh ? You finally gave in to tap water I hope

There are debates over what stabilizer to use with what EM. Urea, diphenylamine, etc. Rosco posted a few interesting things on this matter but I'm not a good enough chemist to have an opinion on that.

XeonTheMGPony - 23-9-2022 at 03:22

Quote: Originally posted by XeonTheMGPony

Add a bit to the methanol and to the water? What do you mean? You add methanol to the water in addition to urea?

Add urea to the recrystallization solvent, urea is soluble in methanol

Add small amount Urea to the iced water bath to crash the super saturated ETN / Methanol / Urea solution in to

ManyInterests - 23-9-2022 at 04:30

I did hear about methanol being used as a solvent. Does it have to be hot methanol? Do you have any idea how much I might need? Methanol is cheaper than acetone and I am out of methanol, so I might as well use it.

Edit: I read that 10g of ETN in 100ml of ethanol. is it similar to methanol? I did see that when crashed into solution it is supposed to form as platets and not the captain crunch consistency of acetone. This sounds a lot better.

[Edited on 23-9-2022 by ManyInterests]

Herr Haber - 23-9-2022 at 07:46

It will definitely have to be hot near boiling and stoppered if possible. There's only 10 degrees between ETN melting point and methanol boiling point. Look at the difference in solubility between methanol and acetone. You will be using *a lot* more methanol.
Take that into account when crashing because you obviously need more water than what would be the minimum with acetone. You're using 3.5 liters so it shouldnt be a problem unless you have a very big batch and had to use a lot of methanol.
You ***cannot* of course heat the water to drive off the methanol if you realize you still have a lot in solution.

If you've already gone through the acetone recrystallization you could also do a simple recrystallization in methanol + urea. No crashing in water. Less hassle

I cant say I like the crystal shape you get from methanol (platelets). Appearance is nice, usage not so much (doesnt flow as well). It also traps a lot more water so drying takes longer and sticks a bit together. Nothing that cant be solved though.

ManyInterests - 23-9-2022 at 07:57

I will be putting in 3.25 liters of water first, and then dumping in the methanol dissolved ETN. If I have more space for water, I'll put it in before.

i won't do too big a batch. If you recall, I did 'final exam' myself with ETN synth and I ended up with 84 grams of final product. I just wanted to see if I can pull it off (and I did). I'll work with 30 gram batches at a time to make sure I don't overwhelm the water.

And methanol has a boiling point of around 65 C while ETN melts at 70C. I'll take that into consideration. I'll monitor the temperature of the methanol and as soon as I see any bubbling I will remove from the heat source and dump it over my ETN. I will use a surplus of methanol to the ETN. So like 350ml to the 30 grams.

Herr Haber - 23-9-2022 at 08:55

ETN melts around 55-61 depending on purity. Methanol boils at 65 so you dont have a big margin.
Because of this you'll probably have to use more methanol than needed because you dont want to have a blob of molten ETN in methanol. And if you let it cool then you'll have a layer of ETN stuck at the bottom of a beaker.
Not the best for the nerves and this is where acetone becomes really useful to clean and save as much material as possible from the mess because you dont really want to scrap if off right?

But I'm pretty sure you already figured that last part out on your own.

I'd recommend starting with a 10g batch, just so you can get used to how much methanol you'll need and how much water to crash it in. If the ratio methanol / water is too high it'll be very obvious to you.

ManyInterests - 23-9-2022 at 14:45

ETN melts around 55-61 depending on purity. Methanol boils at 65 so you dont have a big margin.
Because of this you'll probably have to use more methanol than needed because you dont want to have a blob of molten ETN in methanol. And if you let it cool then you'll have a layer of ETN stuck at the bottom of a beaker.
Not the best for the nerves and this is where acetone becomes really useful to clean and save as much material as possible from the mess because you dont really want to scrap if off right?

Yeah I had that issue happen once where I needed to scrape stuff!

At any rate, I get you. I will use a good excess of methanol.

Like if I want to go with my 30 grams, I will use 450 ml instead of 350. I will dump the hot methanol on top of the ETN and stir them and if I see them all dissolved, I will dump the entire thing immediately into the water.

Edit: ETN melts at 55 to 61? I had to put my hot water bath at 70C to melt cast the ETN into my pen body. Maybe the plastic is a poor thermal conductor. Maybe it could have melted at a lower temp, I dunno.

[Edited on 23-9-2022 by ManyInterests]

XeonTheMGPony - 23-9-2022 at 18:12

never had it stick, I often let it cool int he methanol to form high density crytals

#1 recryst, I use a slight excess methanol so I can filter it with out head aches, to remove any solids and such, second recrsyt, I use just enough to dissolve it all

then under steady stirring and wrapped in towel it is allowed to cool then once room temp I put it in freezer and manually stir so often.

ManyInterests - 23-9-2022 at 19:47

Oh my! I made a ridicules and thoroughly irresponsible mistake... that had no negative consequences.

So instead of recrystalizing 30 grams at a time, I weighed both my batches together and accidentally put the methanol over the whole lot. Interestingly enough, the 550ml (approximately) of boiling hot methanol was sufficient to dissolve all of them.

I then mixed it them to make sure everything is dissolved (98 grams total. 16 grams from my first batch, and the 82 from the other I believe. Seems like keeping the other one open for a few days before doing this did cause whatever solvents to evaporate, going to 82 from 88).

I dumped the whole thing in 3.5 in ice cold water, topped off with more water, then filtered. It'll take quite a few days for everything to dry out, but I will see what I get.

There is very little crunchiness, most of them are very, very cake like, so I predict that it's going to be a very, very fine powder once it is all dry with no chunks or anything. Oh and I made sure to add urea to both the methanol and the water, so this should be the most hyper pure batch.

Edit: So keep a note. Aprox 550 ml will readily dissolve 98g of ETN. It took a bit of stirring (not too much) but it dissolved with what I believe are impurities in the bottom.

[Edited on 24-9-2022 by ManyInterests]

XeonTheMGPony - 24-9-2022 at 04:22

Actualy mixing batches is how you get good uniformity, so this allows for much more accurate loading and testing. Amount is a bit excessive, but that just makes you need more water, so more of an annoyance aspect them levelling the house sort of oops.

Herr Haber - 24-9-2022 at 06:58

Quote: Originally posted by OneEyedPyro

I've found that with ETN the critical diameter is smaller at low densities, cast doesn't seem to have stable detonation below about 8mm and it's not for lack of a strong enough initiation.
Lightly pressed powder will detonate consistently at pretty tiny diameters though.

1 is cast and 2 are pressed. Guess who's who. Diameter slightly above 6mm. These are very old (10 years or so). Dont recall the specifics but probably 700mg + 100 or 120mg DLA as an initiator. Sorry about the sand.
Just look at the size of the fragments. I would call the pressed ones failures.
That's why I disagree when I read statements like the above one. Never tried powder in tiny diameters though.

ManyInterests - 5-11-2022 at 21:57

It is very good. I went out on a field trip today to test out my blasting caps, and I even tried to set off (what I thought was) ammonium picrate. This was my first expedition of the kind and... it's quite disappointing.

I wrote all my notes in a .txt file that I keep stored, but I am not in the mood to rewrite it, so I will put all my notes here for all to see:

The good:

The e-matches were perfect. No failures to ignite whatsoever. Trigger mechanisms also worked without issue. Note on the RF module. Only connect after the charge has been wired and disconnect once it has been fired. Therefore I can safely say that my electric match design is near 100% effective.

List of caps tested:

First four caps made last March. Due to acid remaining in the ETN (not properly washed despite acetone recrystalization) the ETN was significantly degraded. They were set off in a series and all popped quite well, but not as powerfully as expected. Possibly due to the degradation, but a more likely culprit is the the plastic pen body.

Two further caps were tested, the newer ones. Despite the significantly improved melt-cast design, even the 1.3 grams of ETN (1 gram melt-cast) and 0.25 grams of dextrinated NHN, the detonations were not as loud or as powerful as expected.

The attempted main charge of ammonium picrate did not go off. Some fire started but was quickly put out. The lack of detonation could be that the starting picric acid used to make the ammonium picrate was of poor quality and was not recrystalized. The 1st batch was off-color and the 2nd was the salvaged remains of a runaway. a 2nd attempt will be made in the future, but with great care in regards to the manufacture of the picric acid and a recrytalization will be done. Given just how readily the 'picric acid' dissolved in the 6% ammonia solution it could mean that most of it was not even TNP, but possibly a great deal of MNP or DNP (MonoNitroPhenol and Dinitrophenol respective) that was turned into their far less explosive salts by the ammonia.

Another possibility is that the detonator, despite being a 1.3 gram of ETN (1 gram melt-cast) simply didn't work.

The main issue is I feel I was greatly mistaken is the use of a plastic body for the blasting cap. I thought that NHN could easily go DTD in a cap body or sustain the required explosive train. It is possible that the molten plastic is greatly interfering in the process. Even putting the plastic body in a metal casing will likely not help due to the plastic issue. The bic round stic must be retired from further attempts and a more classical metal body adopted.

Another possibility is that the dextrinated NHN is insufficiently powerful. After some conversation with a fellow discord chemist, the NHN doesn't really need to be dextrinated. After reviewing the conservation it might not reduce the explosive power, but it might simply require more power, thus more is required in the cap... either way, experiments will be done with dextrinated vs non dextrinated NHN.

Test done on current supply of NHN should be conducted to see if anything has changed in storage.

Next caps will continue to be electrical, but will use A: Spent firearm shells (will use both 7.62x51mm and the 7.62x54R. Some way to properly press everything through the narrow neck will require experimentation), B: the steel tubes obtained from aliexpress, and c: Aluminum tubes that will be cut to various lengths (I got a tube cutter!) and seal the other end with either epoxy or (following LL's methods), a piece of aluminum foil.

Further caps will feature the same melt-cast ETN, loose ETN, and NHN, but with no plastic wrapper between the NHN and ETN as I am confident that it is not the chemical incompatibility between the two but the acid in the ETN. Which is no longer an issue.

-----

So that was that. My first det cap and how it blew away the wooden block I will write off as a one time fluke, because I could not replicate it. The next time I will want to experiment more.

Laboratory of Liptakov - 6-11-2022 at 02:09

Proof of a good detonator function is the round and precise hole in the steel plate. Wood chips and sound mean nothing....Unfortunately.... :cool:

Hey Buddy - 6-11-2022 at 06:44

For cap bodies, I have found use of 8mm OD stainless steel, Aluminum or Ti drinking straws from china. They can be cut to length with a drill and pipe cutter, then end closed with fireforming on a bearing with a torch or foil-stuffing the ends closed.

There is also a popular 6mm OD SS thermometer probe sheath. They can be found with the ends already closed in 6x50mm lengths.
I haven't used them yet so I can't claim they are in fact suitable but this is a ready-made option.

I believe they are listed on ebay generally as "Temperature Sensor PT100 casing"

SS 8mm straws
https://www.ebay.com/itm/224028065518
6x50mm probe casings
https://www.ebay.com/itm/354323121727

edit: just a recommendation, when testing detonators there is probability there will be failures, and it can be hazardous with several trials. A smart practice I was taught is to leave ends always exposed so that they can be seen unobscured after failures. It gets nerve-racking to deal with failed caps if they are covered with tape etc. from being connected to charges or det cord and the like.

[Edited on 6-11-2022 by Hey Buddy]

Laboratory of Liptakov - 6-11-2022 at 07:39

For laboratory testing and especially reliable DDT with exact results is best steel cavity 6/8 x 50 mm. (on pic.) Or 8/10 x 60 mm. In laboratory conditions is possible trying without the metal (without any) plug. Because any obstacle on output side decrease and distorts results. Even thin alu foil 0.3 mm distorts results. The strength and strength of the wall is decisive for the proper functioning of the DDT. The output side should always be cast or highly pressed EM (segment). Which forms a solid plug on its own. The height of the pressed segment is usually 7 - 10 mm. For second side with wires (or Bickford´s fuse) can be use the glue or else suitable method. For example grain and pressed BP (on picture) , or plasticized BP. For first indicative results, 2 mm structural steel is most suitable. (on pic.)
A lead block is suitable for more accurate measurements (plate dent method).
For the most accurate measurement (plate dent method) aluminum block.

ManyInterests - 6-11-2022 at 09:18

Quote: Originally posted by Hey Buddy

For cap bodies, I have found use of 8mm OD stainless steel, Aluminum or Ti drinking straws from china. They can be cut to length with a drill and pipe cutter, then end closed with fireforming on a bearing with a torch or foil-stuffing the ends closed.

There is also a popular 6mm OD SS thermometer probe sheath. They can be found with the ends already closed in 6x50mm lengths.
I haven't used them yet so I can't claim they are in fact suitable but this is a ready-made option.

I believe they are listed on ebay generally as "Temperature Sensor PT100 casing"

SS 8mm straws
https://www.ebay.com/itm/224028065518
6x50mm probe casings
https://www.ebay.com/itm/354323121727

edit: just a recommendation, when testing detonators there is probability there will be failures, and it can be hazardous with several trials. A smart practice I was taught is to leave ends always exposed so that they can be seen unobscured after failures. It gets nerve-racking to deal with failed caps if they are covered with tape etc. from being connected to charges or det cord and the like.

[Edited on 6-11-2022 by Hey Buddy]

Yes, metal bodies. That's the ticket! I can pick up metal straws at local dollar stores and other places. I don't know their exact diameter is, but they can vary greatly. You mentioned 8mm ID. I will look into that. From what I've seen, real blasting caps tend to have an ID of 6mm or so, but I guess larger can work just fine.

I also have some of those 6x50mm steel thermoprobes. For making smaller (real realistically sized) caps, they can work. I just need to make my ematches as small as possible to allow room at the top for the epoxy plug.

I really want to make a blasting cap as good as a commercial/military cap. my mind is set on it!

For laboratory testing and especially reliable DDT with exact results is best steel cavity 6/8 x 50 mm. (on pic.) Or 8/10 x 60 mm. In laboratory conditions is possible trying without the metal (without any) plug. Because any obstacle on output side decrease and distorts results. Even thin alu foil 0.3 mm distorts results. The strength and strength of the wall is decisive for the proper functioning of the DDT. The output side should always be cast or highly pressed EM (segment). Which forms a solid plug on its own. The height of the pressed segment is usually 7 - 10 mm. For second side with wires (or Bickford´s fuse) can be use the glue or else suitable method. For example grain and pressed BP (on picture) , or plasticized BP. For first indicative results, 2 mm structural steel is most suitable. (on pic.)
A lead block is suitable for more accurate measurements (plate dent method).
For the most accurate measurement (plate dent method) aluminum block.

I have come to accept that you are correct about needing to test against metal and even though the results were impressive my first time around with the wood, I was not able to replicate those results... so even that is a fluke.

I am willing to try to make a melt cast plug. But I don't know how to do it. I melt-cast my ETN by putting it in the pen body (now it will be the metal body) and just put it in hot water (65C) to melt it inside the cap I want to use. But how would you make a simple plug? Because I do want to make the test on metal, as well as doing the 'charge test'. As actually setting off a small charge of insensitive HE to see if it would actually go off.

I did see your video on melt-cast ETN and I am afraid to say I am not willing to try it. Putting it on a teflon frying pan and melting it like that is too scary for me.

[Edited on 6-11-2022 by ManyInterests]

XeonTheMGPony - 20-11-2022 at 07:40

Quote: Originally posted by B(a)P

Quote: Originally posted by karolus28

I'll review it. But that is duly noted. When I make do CHP ones I will use tubes such as these: https://bit.ly/3TenykA

the link shows me a 404, could you post another one?

Ah yes my oldest of friends! I used those tubes for decade, I've since switched to aluminium.

They work excellent as a casing, and can be nickle plated if need be.

Figured I show recites this time, since I don't think I have befor

[Edited on 20-11-2022 by XeonTheMGPony]

XeonTheMGPony - 20-11-2022 at 07:47

what on earth have you guys been doing? I have never even had close to these issues you speak of?!?!

Laboratory of Liptakov - 22-11-2022 at 03:28

XeonTheMGPony.....Finally someone, who can do it quality exact hole in steel..... :cool:

....Thanks for pictures.

Ankit1612 - 22-11-2022 at 06:35

I'm using HMTD as primary explosive. And an empty pen as detonator casing.

I have PETN and Picric Acid which one is best as base charge in detonator?

underground - 22-11-2022 at 07:12

PETN, however i have failed to initiate PETN using HMTD in straw. ETN has no problem thought. Consider making some ETN too

[Edited on 22-11-2022 by underground]

Herr Haber - 22-11-2022 at 10:40

Quote: Originally posted by XeonTheMGPony

what on earth have you guys been doing? I have never even had close to these issues you speak of?!?!

Just exploring the 999 ways that dont work when we know one that works

ManyInterests - 22-11-2022 at 18:04

Yeah, like I really didn't understand why my det caps didn't go off as well as I hoped. Maybe my dextrinated NHN is not good enough? Or maybe I need more NHN in the cap than just 0.25g.

I got some advice to melt-cast the ETN in another beaker or watch glass, grinding it up again, then pressing it into the cap. I still can only hand-press, which is a problem, but I will try with melted-in-cap and melt-cast then pressed.

XeonTheMGPony - 22-11-2022 at 19:19

Yeah, like I really didn't understand why my det caps didn't go off as well as I hoped. Maybe my dextrinated NHN is not good enough? Or maybe I need more NHN in the cap than just 0.25g.

I got some advice to melt-cast the ETN in another beaker or watch glass, grinding it up again, then pressing it into the cap. I still can only hand-press, which is a problem, but I will try with melted-in-cap and melt-cast then pressed.

All mine are pressed, never done melt cast, first 400mg is hard pressed 100mg light press. terribly subjective I know, I do plan to build a press machine that will allow much more quantifiable measurements at some point

Laboratory of Liptakov - 23-11-2022 at 03:36

Casting is much more laborious and the output brisance is no better. When pressed into a solid cavity using a small vise, the density of ETN reaches 1.7g/cc or higher. It's the easiest and fastest. Usually 300 - 400 mg of ETN is pressed. This is followed by manual compression of 100 mg of ETN with hand pressure of approx. 2 - 5 Kg. This is followed by a primary mixture, usually 200 mg. NHN has proven to be an unreliable substance. The most reliable is 200 mg of SA-DS. In its own plastic case together with a resistance bridge. The use of plastic shrink tubing has been proven. SA-DS is poured loosely and secured with a piece of nitrocellulose cotton wool.

The side with the wires is completed with baking soda. And drips 4 drops of instant glue. This results in a very strong plug made of a relatively inert and cheap and available material. And it holds immediately.
plug.jpg - 80kB

Industrial Adhesive - 9-12-2022 at 06:56

Quote: Originally posted by MineMan

Very cool! Would be curious about PETN and nano Al. Which can be set off by a low powered laser (1watt) no primary needed.

would something like a fibre op cable be used as a lead?
i wonder if something with a higher thermal conductivity like copper would have a greater effect? problem is how easy it is to oxidize Al compared to Cu making Al more desirable. im intrested if nano Cu/PETN could have a similar effect. or maybe some other nano metal powders.

ManyInterests - 9-12-2022 at 09:18

Casting is much more laborious and the output brisance is no better. When pressed into a solid cavity using a small vise, the density of ETN reaches 1.7g/cc or higher. It's the easiest and fastest. Usually 300 - 400 mg of ETN is pressed. This is followed by manual compression of 100 mg of ETN with hand pressure of approx. 2 - 5 Kg. This is followed by a primary mixture, usually 200 mg. NHN has proven to be an unreliable substance. The most reliable is 200 mg of SA-DS. In its own plastic case together with a resistance bridge. The use of plastic shrink tubing has been proven. SA-DS is poured loosely and secured with a piece of nitrocellulose cotton wool.

The side with the wires is completed with baking soda. And drips 4 drops of instant glue. This results in a very strong plug made of a relatively inert and cheap and available material. And it holds immediately.

I saw your video on double salts. I also read about them. They are interesting (especially your use of an olive jar exactly like the improvised munitions guide!) but in all honesty I really believe that the NHN should have worked. I will add more next time.

And while melt-casting isn't much better than hard pressed ETN, I don't have a press to press it with, so I cannot get the 1.7cm3 density by pressing by hand. Melt-casting in the detonator as I have been readvised again is much easier and I can do it. I will try that, add more ETN on top after it cools down and then 0.4 or 0.5g of NHN pressed in by hand as hard as I can. Melt-cast ETN is pretty much the easiest way to get the density to 1.7 or 1.8. ETN is brisant enough on its own, I don't need more! 1.3 or so grams of ETN in a detonator is powerful enough for almost anything.

I also did make some CHP BTW. But the copper oxide I ordered is probably BS which is why I have a LOT of containmation. I've also seen some that burned super fast while others didn't. I ordered more copper (II) oxide that I hope is more pure so I can use it, since I have lots of ammonium perchlorate left (around 100 grams, or a little less. Either way it is enough for a good amount of CHP to make) I just need to make or buy more ammonia to make it as well since my 28% supply is scant at the moment.

specialactivitieSK - 4-2-2023 at 03:47

I read about Bi2O3+Al (maybe with PETN) as potencial mixture for blasting cap.

Herr Haber - 4-2-2023 at 05:59

Quote: Originally posted by specialactivitieSK

I read about Bi2O3+Al (maybe with PETN) as potencial mixture for blasting cap.

Dragon Egg composition as an initiator ? Why not...
I've always wondered what would happen if the beads in commercial compositions were bigger but never dared try

Bert - 4-2-2023 at 19:11

I've always wondered what would happen if the beads in commercial compositions were bigger but never dared try

Although the dragons egg granule comps behave quite snappy, they have a limitation in effective sizes- The amount of comp which has reached the temperature for effect to occur GOES. The interior of any oversized chunk of comp DOES NOT go. The under heated, unreacted ballance gets broken into crumbs and flung about- Some of it MAY smolder and go "bang" later- a great deal of it generally will not.

Herr Haber - 5-2-2023 at 16:16

What if I add neutron reflectors ? /joking
Thanks Bert for that very interesting information. I understand what you mean. I read a couple of threads on the mixture but may have missed some.
My friends are going to be so dissapointed. Some asked if I could do something "bigger" than store bought crackling fountains...

Anyway, sorry for the off topic.

MineMan - 6-2-2023 at 21:01

I've always wondered what would happen if the beads in commercial compositions were bigger but never dared try

But what about confined in a metal tube? I saw some mixture on Russian YouTube… that was similar and it DDT in the open.

Bert - 7-2-2023 at 17:52

Quote: Originally posted by MineMan

But what about confined in a metal tube? I saw some mixture on Russian YouTube… that was similar and it DDT in the open.

Both of the common lead oxides (litharge, minium) when used as oxidizers in pyrotechnic compositions or unthinkingly mixed with fuels in the lab have surprised a few people with how violent they can be- I've no idea what you saw, could you find it and post WHAT the mixture was/what it did to make you think it was a primary?

[Edited on 2-8-2023 by Bert]

Laboratory of Liptakov - 8-2-2023 at 04:57

Has anyone tried the initiation properties of Bi2O3 + Al...? In a solid cavity...?...Or do only I have to try ..?...A like usually first in whole world...?.... :cool:

MineMan - 8-2-2023 at 18:17

Quote: Originally posted by MineMan

But what about confined in a metal tube? I saw some mixture on Russian YouTube… that was similar and it DDT in the open.

I cannot. It was a bismuth based thermite. Nonetheless those tend to be sensitive. Obvious step would be mixing with ammonium perchlorate. Anyways, I have yet to find anything that is better than my nano mixtures except some stuff explosive laboratories did with partially nitrated organics mixed with Iodates. I was not able to duplicate. Ammonium perchlorate and aluminum is still in my mind the safest DDT mixtures. I have seen detonation with only micron aluminum in the correct ratios. But nano is really needed, although low order detonations of these mixtures will kick secondaries, period. Even flash will set off ANNMAL mixtures with full force.

People miss the forest for the trees in these DDT mixtures. Either use flash, or use a very engineered nano mixture.

MineMan - 8-2-2023 at 18:17

Has anyone tried the initiation properties of Bi2O3 + Al...? In a solid cavity...?...Or do only I have to try ..?...A like usually first in whole world...?.... :cool:

Mix it with ammonium perchlorate, we need some gas generation. Yes. You do

)

Bert - 8-2-2023 at 18:38

Anecdotally, have NOT tried this- I prefer not to use lead in fireworks mixtures:

Red thermite (lead tetroxide/elemental silicon) is pretty shock sensitive, made with fine enough mesh ingredients, explodes rather than burns.

Might this be what the Russian YouTube guys were playing with?

I think there is some Bismuth oxide around here, was looking at the non lead dragon eggs mixture years ago but then got too busy, then I got licensed and REALLY got too busy, stored it away and never made any crackle with it.

I recall the bismuth oxide dragons egg mixture calling for a few % of black copper oxide as well. I think I found that one published in a PGI Bulletin, perhaps 20 years back. Where DOES the time go?

[Edited on 2-9-2023 by Bert]

MineMan - 8-2-2023 at 21:44

Anecdotally, have NOT tried this- I prefer not to use lead in fireworks mixtures:

Red thermite (lead tetroxide/elemental silicon) is pretty shock sensitive, made with fine enough mesh ingredients, explodes rather than burns.

Might this be what the Russian YouTube guys were playing with?

I think there is some Bismuth oxide around here, was looking at the non lead dragon eggs mixture years ago but then got too busy, then I got licensed and REALLY got too busy, stored it away and never made any crackle with it.

I recall the bismuth oxide dragons egg mixture calling for a few % of black copper oxide as well. I think I found that one published in a PGI Bulletin, perhaps 20 years back. Where DOES the time go?

[Edited on 2-9-2023 by Bert]

May have been copper oxide, bismuth oxide and magnesium. I can’t remember. All these thermites are too sensitive. Nano thermites were the rage… till we realized they are more sensitive than primaries. It’s hard to beat wax coated aminoguanidine nickel perchlorate. There are exotic insensitive primaries that are immune to friction and impact (more so then PETN ). But they are exotic. Anyways. The issue with primaries is one batch may go off with a tap another won’t start all. Nano engineered ammonium perchlorate mixtures are, something else. It’s an engineering marvel. Burns like a sparkler, cannot catch in the open but ddt confined

what other primary self extinguishes in the open???

Herr Haber - 9-2-2023 at 09:23

I recall the bismuth oxide dragons egg mixture calling for a few % of black copper oxide as well. I think I found that one published in a PGI Bulletin, perhaps 20 years back. Where DOES the time go?

[Edited on 2-9-2023 by Bert]

Doesnt seem to be any copper in those.
I crushed a couple of them, added a few others full in a bit of water then added a few drops of H2SO4.
Initially there were a lot of bubbles, a cloudy suspension I attributed to Al or Bi2O3 reacting with the acid but no blue.

Raid - 9-2-2023 at 11:16

If you don't have metal or aluminum tubing to make det-caps I have a solution and it's much cheaper.

get some 1/4 inch vinyl tubing, the stuff that I got was called rain-drop tubing or something like that.
next, you're going to cut off around 3-4 inches of the tube.
clamp one of the ends in a wrench and melt it with a lighter or something. While hot, press the end on some glass or a metal pan to seal the end well.
now if you did everything correctly you should have a cheap yet well-functioning det-cap.
I like to fill the end with around 1cm of well-packed ETN and the rest with TATP or HMTD.
having the 1/4 inch tubing allows for little room between the edge of the tube and the fuse I was using.
I use the visco fuse from cannon-fuse.
if you're going to be using store-bought electric fuses then they should fit perfectly with little to no room.
however if your going to be using DIY eclectic fuses your going to have to make them quite small to be able to fit in the tubing.

Bert - 9-2-2023 at 12:21

I believe this is the mixture I'm recalling.

Screenshot_20230209-141709_Samsung Internet.jpg - 67kB

Bert - 9-2-2023 at 15:13

Quote: Originally posted by Raid

If you don't have metal or aluminum tubing to make det-caps I have a solution and it's much cheaper.

Yup, your ban is over and name isn't "PINKBOII" any more.

I strongly suggest you do not play with explosives, above and beyond that, I suggest you (and everyone else) never play with explosive organic peroxides.

Why not?

https://youtu.be/0Et-fyyBqyE

That kind of thing seems to happen to people who make organic peroxides. A lot.

[Edited on 2-9-2023 by Bert]

Raid - 9-2-2023 at 15:36

I don't "play" with them. I only use it because its cost effective.
I've also seen that video before, I feel bad for the guy.

[Edited on 9-2-2023 by Raid]

mayko - 9-2-2023 at 18:47

Quote: Originally posted by Raid

I only use [organic peroxides] because its cost effective.

"penny wise and pound foolish" seems an understatement here.

Microtek - 9-2-2023 at 23:34

I agree. If you are serious about experimenting with energetics, you should transition to more predictable primaries as soon as possible. I'm sure many of us have started out with peroxides, but those of us that are still around quit them long ago.
The economic aspect is only relevant if you use them for other things than just primaries and if that is the case, you are almost certainly going to kill yourself with it.

Raid - 10-2-2023 at 06:08

I use NHN now, much better and safer.
although when I make organic peroxides they seem to be much less friction and shock sensitive than what people on YouTube make.

[Edited on 10-2-2023 by Raid]

Microtek - 10-2-2023 at 14:22

Yes, peroxides are not necessarily extremely sensitive, the problem is the unpredictability. TATP, for instance, can sublimate and grow more sensitive, large crystals in whatever container you store it in. In the threads of a screw-on cap maybe...

It is good to hear that you have switched to NHN, that is an excellent choice.

Raid - 11-2-2023 at 12:24

yeah, I've heard about TATP detonating due to the sublimation of it on a screw-cap. Luckily I have never had the problem, probably because I don't use screw caps, I only use plastic bags.

Raid, what is the outdoors temperature where you are at right now?

Bert - 12-2-2023 at 06:34

Quote: Originally posted by Raid

Luckily I have never had the problem, probably because I don't use screw caps, I only use plastic bags.

Non static plastic bags, of course. In a sufficiently humid environment, with ESD protection bleeds through a hefty resistor to ensure any generated potentials dissipate slowly.

You DO know about primary explosives sensitivity to explosions from electrostatic discharge (ESD), of course. And can post here a table (or SEVERAL tables) showing the joules/uf@kV of ESD capable of causing common primary explosives to explode. In some cases, the energy required to cause an explosion wouldn't even be noticed by you if you if a spark with that energy discharged from your fingertip to a grounded surface.

That information is on this site and in many other places. I'm sure you will research it and post it to this thread by tomorrow.

Laboratory of Liptakov - 12-2-2023 at 07:08

Quote:

Every year, several thousand researchers grow up in the world. Of these, several hundred will visit sciencemadness. Of these, most follow the advice and experience of the wise. And of these, several individuals do not follow anything at all. And they show off in front of others as brave young male monkeys.
Conclusion: I am convinced that we are descended from apes.

No arguement here-

https://youtu.be/aRHqs8SffDo

[Edited on 2-12-2023 by Bert]

Bert - 12-2-2023 at 09:25

Quote:

Yeah, I know about ESD. and to counter that I store in a ESD proof bag I got when I built my PC.

and the temp where I live is around 0-30 ish

°F or °C? Always specify units... Around here, SI units would be best.
----------

Great! I am pleased that you know all the answers, it must be an impressively large anti static bag for you to climb inside and fabricate/test your detonators.

Tommorow I will look for your post on relative ESD sensitivities of a range of primary and secondary explosives. Including some typical values for charges developed by a human body under various conditions of temperature and humidity while conducting various activities...

[Edited on 2-12-2023 by Bert]

Raid - 12-2-2023 at 09:33

well if you live in America it would be F and yes its a very large anti-static bag, it fits my whole house inside.

Texium - 12-2-2023 at 10:05

This is an international science forum. Specifying units of temperature is important, and without specification it’s assumed to be Celsius by default, ‘Murica or not.

Herr Haber - 12-2-2023 at 10:38

Doesnt seem to be any copper in those.

@Bert
Well... I was wrong ! I left the small beaker for a few days and after settling I am left with a very light blue solution.
I used "a few" dragon eggs but certainly less than a gram which would amount *at most* to 150mg given your composition. Said composition doesnt include the priming (black powder) on the eggs that seems to constitute most of the sediment (carbon).

Fantasma4500 - 19-2-2023 at 02:26

dragon eggs have practically zero brisance, poor predictor for it being useful for initiation
i have seen dragon eggs on youtube that were pretty big in size and seemingly went off by fuse right away without smoldering first
however the smoldering part i have seen with copper sulfate and copper oxide compositions where its first superheated and then loudly and sharply explodes in open air, its possible to "charge" regular flashpowder by heating it up first as well

mixtures of our beloved sugar nitrate with primary-like binary mixes is more interesting, armstrongs mixture and sugar nitrate was found capable of detonating but the guy who played around with it didnt bother finding a working ratio of stability and detonating in open air, he rather just put a core of flashpowder sorrounded by the sugar nitrate

if you must, 10mm aluminium tube with 500mg of the sugar nitrate sealed in by 2 1mm aluminium foil discs, then a slowburning composition- such as liptakovs caramelite and a fuse leading into this with some KClO3 sugar mix to carry ignition, secured with cotton wool goes well, appears that maybe 50mg of the nitrate burns off rapidly whereafter it goes high order, the aluminium tube does not at the bottom get hot enough to ignite nitrocellulose- this means the tube doesnt get hotter than 120*C - essentially its safe to use in combustible charges without risking the charge burning up before initiation goes

specialactivitieSK - 31-5-2023 at 08:36

Blasting cap protector

B(a)P - 31-5-2023 at 14:54

Quote: Originally posted by specialactivitieSK

Blasting cap protector

I would be interested to know more.
What does this actually do?
Is it to protect the user from an accidental detonation or the detonator from an accidental stimulus?
Without context it kind of just looks like a pipe bomb.

specialactivitieSK - 31-5-2023 at 23:03

protect the user from an accidental detonation

Microtek - 1-6-2023 at 08:18

Have you tried setting a detonator off inside it on purpose (and with proper safety measures)? A number 8 equivalent detonator really is quite powerful...

Herr Haber - 1-6-2023 at 14:53

Have you tried setting a detonator off inside it on purpose (and with proper safety measures)? A number 8 equivalent detonator really is quite powerful...

When I thought about the construction of such a device I imagined it would probably be better to have a thick walled inner tube with a lot of holes and an outer tube with less holes and kaowool in between all welded on a round plate and screw top on the other end
I realize that looks like a bulky sound supressor.

dettoo456 - 1-6-2023 at 16:12

Haber, a suppressor-like design that has some sort of baffles (facing the center of the cylinder rather than perpendicular like for a firearm) might work to break up small enough blastwaves for <1g amounts of EM. Although I think at that scale, the blast wave is less important to minimize than the shrapnel. If it’s possible to use a fiberglass insulated, kevlar or weaved carbon tube (wrapped around the long edge of the cylinder), the shrapnel and blast wave of an accidental detonation could be ‘caught’ by the threads of composite fiber (kevlar, carbon fiber, etc).

If you are trying to construct a magazine for bulk storage of EM though, with no shrapnel/metal casings involved, a setup incorporating big spikes (like sound deafening foam but made out of wood or some other compressible material) and baffles might be a good way to break up or at least slow down a blast wave before it can break out of the magazine walls.

Never store EM in a non-compressible material environment.

B(a)P - 1-6-2023 at 16:55

Have you tried setting a detonator off inside it on purpose (and with proper safety measures)? A number 8 equivalent detonator really is quite powerful...

Plus one to this.
How is it constructed, what are the materials?
Do you have a photo of the internals?

ManyInterests - 28-6-2023 at 21:28

A while ago I made blasting caps using plastic pen bodies, but I have a feeling that the hardness of the plastic might have been the thing that was interfering with the explosive train. I remember once thinking about making blasting caps out of cardboard, but I never found a suitable tube for it.

I did, however, get some large paper straws (the type people use to drink bubble tea) and the larger diameter would make things easier for loading and pressing. But I also think that military caps made using cardboard bodies (such as Soviet detonators during WW2) had similar strength. Obviously some waterproofing would be needed, or at least wrapping them in electrical tape should do the trick.

I made a pair with CHP, albeit I didn't do more than hand pressing since I am still to scared to try to use my C-clamp to press harder on the stuff. I will need a better setup for it as well.

I want to try to see if I can meltcast ETN in a waterproofed paper cap. I sealed the end with 5-minute epoxy and I do believe that the melting point of epoxy resin is easily over 100C, so no need to worry about the plug melting on that end.

ManyInterests - 16-10-2023 at 18:57

So around two weeks ago I wanted to go out to a location I went to previously and test out my caps with a proper steel witness plate (pictured below) but sadly the weather was not what I anticipated. It was raining HARD, so I had to cancel my trip.

I once did ask how I would put my caps without gluing them on a metal plate, but I did find the following at a local hardware store (they also have the benefit of being dirt cheap). Would a cap taped to the side of the plate allow for proper force to be directed downward for a proper test to happen?

I promise, this is the last question I will be asking about caps before I go out and finally blow some holes into metal and see how my caps work.

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B(a)P - 16-10-2023 at 19:11

Tape will work fine as you have it. Best of luck with the weather for your next outing.

ManyInterests - 16-10-2023 at 19:48

Quote: Originally posted by B(a)P

Tape will work fine as you have it. Best of luck with the weather for your next outing.

Thanks. Many of those caps were made last summer and I am itching to set them off. I also used the NHN/chlorate mixture that is covered in another thread. I will also be trying straight NHN in a brass 5.56x45mm/.223 case and one of the 1.2g of ETN + 0.5 of straight ETN in a longer, but slightly narrower, metal body.

That metal body you see appears to be ideal for most caps, since it is 8x50mm, given how loose the 6.35mm dowel that I used to press the stuff in there was, I assume it is a 8mm OD but 7mm ID, which makes it a very good diameter for most caps.

OneEyedPyro - 16-10-2023 at 19:55

A while ago I made blasting caps using plastic pen bodies, but I have a feeling that the hardness of the plastic might have been the thing that was interfering with the explosive train. I remember once thinking about making blasting caps out of cardboard, but I never found a suitable tube for it.

I did, however, get some large paper straws (the type people use to drink bubble tea) and the larger diameter would make things easier for loading and pressing. But I also think that military caps made using cardboard bodies (such as Soviet detonators during WW2) had similar strength. Obviously some waterproofing would be needed, or at least wrapping them in electrical tape should do the trick.

I made a pair with CHP, albeit I didn't do more than hand pressing since I am still to scared to try to use my C-clamp to press harder on the stuff. I will need a better setup for it as well.

I want to try to see if I can meltcast ETN in a waterproofed paper cap. I sealed the end with 5-minute epoxy and I do believe that the melting point of epoxy resin is easily over 100C, so no need to worry about the plug melting on that end.

More strength and confinement with a cap body is generally what you'd want. A paper straw isn't an improvement by any stretch.
You can find lots of suitable tubes of varying sizes at a dollar store or the arts and crafts section in a department store. Coloring markers and such.
Some 9v batteries contain 6 small 1.5v batteries wired in series that are just about the perfect size for a cap.

ManyInterests - 16-10-2023 at 20:35

Quote: Originally posted by OneEyedPyro

Yeah I figured that out. The batteries inside some 9vs are AAAA batteries. They can be purchased separately, but in many cases they're so hard to find nowadays that some people just get alkaline 9V batteries and open them up to salvage them. It's actually rather hit and miss. I've opened up many 9Vs from various brands (alkaline 9Vs) and some had column type, while others had the AAAAs.

But using them would be tricky since they need to be well cleaned from within. That is an annoying endeavor. I would rather just by the 304 steel capillary tubes that are already sealed on one end and call it a day. when melt-casting ETN in them, exceptional care must be taken since molten ETN is highly sensitive when with steel, Though I did melt-cast ETN in them several times without issue.

One thing I learned is that it is just better to use a metal cap body. I'm glad that I initially used plastic pen bodies because it did let me see if anything was going on with the material inside. When I first made ETN, I didn't wash it enough to get rid of all the acid, so a lot stayed left over. While it didn't appear to degrade it when I was storing it in a tupperware, but it did seriously degrade when I loaded it into a bic round stick pen body. After I properly cleaned and purified the ETN, all subsequent pen body caps showed no sign of degradation. While I did put a small cling film barrier between the ETN and the NHN, I don't think it was the NHN interacting with the ETN that was causing it, since I did make a small mixture of the two and let them sit together for a few weeks before disposing of them, and they did not show any signs of discoloration or decay.

In the other thread about mixing a 600:400mg ratio of NHN and sodium chlorate (with 20mg of dry bar soap added and minimum water) he said that if this mixture was put in a plastic pen body it would still work to set off ANFO. The issue with this is that my pen bodies are too narrow for that, and I would rather just use metal.

dettoo456 - 15-11-2023 at 12:04

I apologize if it’s been mentioned before in this thread or somewhere else, but I think spent 22 win mag brass (properly cleaned and polished) could work well as a det cap for both standard fuse and e-match caps. They are around the right ID of a little under 1/4” and are easy to widen and crimp as needed. E-matches sold in the US (the ones with blue & white wires and a red cap to surround the match head) fit snugly inside the brass with a small amount of pressing and 1/4 fuse can be made to fit as well. I found that a rounded steel rod (like a centering punch) and a few blows from a rubber mallet can widen the case ID to 1/4” no problem.

I figured a priming mix of dextrinated AgNTz against the match/fuse followed by a small cotton plug and then pressed, waxed PETN or RDX behind could work. The only issue would be space since the overall length of the casing is about 1” (25mm) and you’d need a solid 5mm or more just for the crimp/glued portion of the cap.

If anyone has info on using spent rimfire casings as caps or the use of AgNTz as a primer I’d be glad to discuss. AgNTz really doesn’t have much info relating to practical use, all I have read is that it can’t be used in combination with Al metal, tetrazene, or MTX-1. It is compatible with RDX but I haven’t heard about it with nitrate esters.

OneEyedPyro - 17-11-2023 at 13:20

Quote: Originally posted by dettoo456

I apologize if it’s been mentioned before in this thread or somewhere else, but I think spent 22 win mag brass (properly cleaned and polished) could work well as a det cap for both standard fuse and e-match caps. They are around the right ID of a little under 1/4” and are easy to widen and crimp as needed. E-matches sold in the US (the ones with blue & white wires and a red cap to surround the match head) fit snugly inside the brass with a small amount of pressing and 1/4 fuse can be made to fit as well. I found that a rounded steel rod (like a centering punch) and a few blows from a rubber mallet can widen the case ID to 1/4” no problem.

I figured a priming mix of dextrinated AgNTz against the match/fuse followed by a small cotton plug and then pressed, waxed PETN or RDX behind could work. The only issue would be space since the overall length of the casing is about 1” (25mm) and you’d need a solid 5mm or more just for the crimp/glued portion of the cap.

If anyone has info on using spent rimfire casings as caps or the use of AgNTz as a primer I’d be glad to discuss. AgNTz really doesn’t have much info relating to practical use, all I have read is that it can’t be used in combination with Al metal, tetrazene, or MTX-1. It is compatible with RDX but I haven’t heard about it with nitrate esters.

.22WRM having a .224 ID you can use a .22LR or better yet .22 short as a plug and housing for the primary since they are heeled type cartridges.
I've done this with SADS/ETN to decent success by pressing and gluing the cases together. The charge is a bit small for my liking and the rims can be an issue when inserting or attaching to a main charge but they will set off ANNM and Tannerite just fine.

ManyInterests - 25-2-2024 at 00:47

OK so finally I drove out in the middle of nowhere to blow some caps. I originally intended to set off 6 caps, but I had some issues and some hestitation. I tried to set off 3, but one had an issue and didn't go off, but the other 2 did.

The set up was that I went out into a snowy field and partially buried the witness plates with the cap taped to it and then set it off. As it was resting on snow, the explosion pushed the entire thing down instead of blowing a hole on it. It isn't the most ideal of circumstances, but I did what I could under the circumstances. I dug the metal pieces out after popping them.

I put an intact piece of metal for comparsion. The bent one used a 0.9g of NHN/sodium chlorate charge, while the really warped one used a 100mm long cap with 1.1g and 0.3g of melt-cast and powder ETN respectively, and 0.5g of NHN as the primary.

I think both of them are quite the success.

dettoo456 - 25-2-2024 at 13:22

What did you do with the UXO cap? I know the standard procedure is to wait 20 min, fire again, then wait 20min and set it off with a reliable remote charge but there aren’t many instances of a well-documented situation like that.

Also, I’d assume those pieces of metal should’ve been decimated with the close to & above 1g quantities of EM. Though, the only real point of the cap is to get a secondary initiated, and that can be done with <800mg PETN in some cases.

ManyInterests - 25-2-2024 at 15:36

I did wait, and I probably gave it more than 20 minutes, too. I moved it aside to detonate the others. The thing did not go off.

I should have written why I suspected the other cap didn't go off (it is with me right now) is that I was trying to see how much I can cram into it. I used some of my poor quality NHN (it doesn't burn very fast) and did with the sodium chlorate addition and soap. As I was plugging in the e-match, it didn't go all the way in like in my other caps. I still put in some epoxy and due to the looseness of it, I think there was a layer of epoxy between the e-match and the epoxy that blocked ignition.

I made a 2nd one like it, but I did not try to set it off. The next time I go out. I will tape them together with another cap I know will go off and have them all pop together.

Quote:

Also, I’d assume those pieces of metal should’ve been decimated with the close to & above 1g quantities of EM. Though, the only real point of the cap is to get a secondary initiated, and that can be done with <800mg PETN in some cases.

That is true. This test was to simply get to make sure that my caps function as intended and can do the job. I had difficulties with other caps in the past, but that was due to them using plastic pen bodies. The reason why there wasn't more damage to the plates is because there was plenty of space for the metal to be forced into (snow isn't exactly hard). If I placed the plates on a solid surface there would probably be a lot more visible damage to the plates. Even the pure NHN one (NHN-chlorate mixture) was quite powerful and I think it'll set most anything off. The one with the 1.1g ETN charge is extremely powerful.

At this point I am confident with these and the next time I go out I will bring a small ammonium picrate charge (in a thick cardboard tube) to try a 1.1g of NHN-sodium chlorate charge and se if it'll detonate. I made ammonium picrate specifically for this test: It is the most insensitive secondary outside of ANFO.

Microtek - 25-2-2024 at 23:44

If the caps detonate fully, it won't matter what it is resting on. Like shooting an apple hanging on a string, the event is much too fast for the target to move anywhere before it is penetrated. I think you should save your picrate for when your caps work better. Also, I think ammonium picrate is generally used with a booster, so you should a least use a very beefy detonator.

ManyInterests - 26-2-2024 at 02:38