Sciencemadness Discussion Board

Det Cap Strategies

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twelti - 17-3-2019 at 14:20

Having done a lot of reading here and elsewhere, a question arises. It seems there are two strategies for making caps. One is to use a primary that needs confinement to achieve DDT. So, safer to work with before it goes into the detonator, but probably needs metal tube to work. The metal tube isolates the primary and secondary (good) but would create shrapnel if it detonates prematurely (bad). Other way is to use a primary that does not need (much) confinement. I have seen peroxide primaries put in straws for example, or maybe SADS, or the like. It is perhaps not as safe to work with (all other things being equal), and less protected in the less rigid tube (bad), but would be less dangerous if it exploded (good). Is this a correct assessment? Which way is safer overall?

type detonators

Laboratory of Liptakov - 17-3-2019 at 15:07

Table:
Low senzitive primary : manipulation, storage ..................+
...........................................filling.......................................+
.......................solid cavity + but production -.....................0
hard shrapnel .................................................................... -


High senzitive primary : manipulation, storage ................... -
filling.................................................................................... -
........................soft cavity - ......(production +)......................0
soft shrapnel............................... ........................................ +

Herr Haber - 18-3-2019 at 04:39

The assessment is correct.
I'd follow LL's results.


Deathunter88 - 18-3-2019 at 21:44

Keep in mind metal fragments are much easier to locate in the body than plastic pieces. (Not saying which one is better, just something to note.)

Laboratory of Liptakov - 19-3-2019 at 03:09

Critical and most worst operation is always filling and pressing. In this operation arises 90% incidents. Therefore is much better use low senzitive materials. For example Tetraamine copper-hexamine perchlorate. (TeCHP or CHP marked ) Which is primary and secondary substance in one. With low senzitive on the friction, but with high detonation pressure (20 - 25GPa) in solid cavity at density 1,8 g/cc or higher. On air only burn, but in metal cavity goes into detonation. In paper or plast cavity not. But at slow heating in aluminium foil confinement, 5 layers, can cross to detonation also. CHP is possible mixed in any ratio with ETN. For example 80:20 or 50 :50 or 25: 75. Results in solid cavity is always same. Full detonation. Even 20 % of CHP can force full detonation on ETN. But only in solid cavity. Most easy for filling detronators is ration 50:50. For all segments. For hogh pressed output segment and also for starting segments.

Rocinante - 19-3-2019 at 14:18

thin 0.3 - 0.5 mm aluminium is the 3rd option

overall, sturdy plastic or thin aluminium is the best option

thick metal walled detonators have only one real advantage - they are safe from friction induced detonation (pulling on the e-match cable)


XeonTheMGPony - 19-3-2019 at 16:37

Why re-invent the wheel, industry standard practices, over 60,000,000 million made a year with very few if any defective units or detonations unintended.

Do research, pick a form factor, make some basic tools and be don with it.

I use two standard of tubing, 7mm od 6.5mm ID or 6mm Od, and 5.5 ID

I get high quality nails, then lath them down to the size of the tube then a hair more to allow clearance and that has a paper spacer to ensure the metal never makes contact to the tube.

Base charge is pressed in, primary charge is pressed into a solid paper tube that firmly fits in the tube, so on.

Very safe, very reliable, very simple, and each stage can be don on mass.

What gets you in danger is changing things up all the time, not having a solid system in place, and good job specific tooling, it doesn't need to be fancy or high tech, it just need be made for the task at hand

MineMan - 19-3-2019 at 21:23

I know of no perfect system. If you can do what pyro guy says if you have paper tubes that fit in. But I don’t see how that works. Because you need to seal the end of the paper tube, then the primary is not against the main attraction... the main charge. TBH it’s tuff. But I have some OCD so nothing seems safe.

Laboratory of Liptakov - 19-3-2019 at 22:33

Anyway, most researchers will still use straw and organic peroxide + ETN. And the safe and quality detonators still stay only in discuss on the science madness.

underground - 20-3-2019 at 01:40

You can also construct an EBW device for safe detonations. Use the search engine and you will find lots of information.I am planning to built one in the near future, i will post it on SM then i will finish it.

[Edited on 20-3-2019 by underground]

XeonTheMGPony - 20-3-2019 at 04:04

made entirely out of paper, was a test of concept

then my more standard units


I'm not that friendly!.jpg - 111kB Bang!.jpg - 125kB bottom rolled.jpg - 137kB

metal dets.jpg - 390kB

XeonTheMGPony - 20-3-2019 at 04:16

Quote: Originally posted by MineMan  
I know of no perfect system. If you can do what pyro guy says if you have paper tubes that fit in. But I don’t see how that works. Because you need to seal the end of the paper tube, then the primary is not against the main attraction... the main charge. TBH it’s tuff. But I have some OCD so nothing seems safe.


the small paper tube for the primary is open at both ends it is only a confinement re enforcer and carrier for the primary, flame catcher mix, and delay element if any

Parchment paper is used to prevent any sticking to the mold / press it does not interfere in any system thus far and if desired easily removed

Reason is the most dangerous part of the whole venture is compressing the azide/styphnate pellet, if it goes off you get paper confetti and some lead vapor and odds are sore ears.

Once you have the primaries pressed, they can be placed in the tube, I usually put some loos main charge in, then press the assembly down, this forms a perfect interface with a small amount of low density base charge to ensure full effective initiation.

the bridge wire is set in some wood dowel, the wires are glued in with wood glue after the resistance wire been attached (this rests in a cut groove of the wood), once that assembly is dried, a low viscosity mixture of NC in Acetone with a priming mix added is dripped onto the bridge wire grove (I have found with my formulation 3 drips is more then good enough to both glue every thing solid and ensure a powerful initiation flash

Back in the day this was Mercury Fulminate, in this decade it was HMTD, I am now going to be using Lead styphnate.

I'll stop befor this becomes a practical tutorial, but now you under stand how every stage is well divided, so any accident is unlikely and if one does occur is well mitigated to a very small amount of working material

Herr Haber - 20-3-2019 at 04:22

@MineMan: if I understand Xeon's idea correctly

1 Take your Al tube
2 Fill it with a secondary
3 Meanwhile find paper tubes that would fit snugly into you Al tube and cut them to the desired size so they hold the amount of primary you want
4 Fill those paper tubes with the primary and I suppose a binder
5 Drop 1 of these "primers" in your Al tube
6 Finish as usual & crimp

XeonTheMGPony - 20-3-2019 at 04:29

Quote: Originally posted by Herr Haber  
@MineMan: if I understand Xeon's idea correctly

1 Take your Al tube
2 Fill it with a secondary
3 Meanwhile find paper tubes that would fit snugly into you Al tube and cut them to the desired size so they hold the amount of primary you want
4 Fill those paper tubes with the primary and I suppose a binder
5 Drop 1 of these "primers" in your Al tube
6 Finish as usual & crimp


Correct, I wind my tubes to shape with normal printer paper that been soaked with watered down wood glue (Working on a better method as it gets tedious)

The fit is very tight so they need to be pressed into the aluminium tube, so they stay put no glue needed, but a dash is recommended.

Laboratory of Liptakov - 20-3-2019 at 13:14

@...XeonTheMGPony.... The last picture seems as good detonator for insert to any plast...Muhaha....:cool:...LL

Rocinante - 21-3-2019 at 04:17

This is the basic principle: keep your hands away from the explosive (applies to all types of blasting caps)

https://commons.wikimedia.org/wiki/File:TATP_blasting_cap_di...
https://commons.wikimedia.org/wiki/File:Blast_mittigation_de...
https://commons.wikimedia.org/wiki/File:Filling_blasting_cap...

Laboratory of Liptakov - 21-3-2019 at 10:29

I use better principle: Keep your the thinks away from HMTD and TATP....:cool:-.....LL

MineMan - 21-3-2019 at 13:49

I just don’t get how the primary does not fall out of the paper tube...

Anyways. With NiGKCLO4. I think one can just have 100mg of primary in a 2-3mm THIN Al tube. 100mg of 32GPa should do almost everything. You only need to press one time. Just FYI. Test confirm these small caps destroy 2layers of steel Kevlar gloves. They dent a quarter too.

Just put it in a vice. And bingo. I thinks that’s the easiest safest way... if it goes you don’t have copper pieces that I have witnessed going through a steel cooking pot!

Rocinante - 21-3-2019 at 14:25

"Test confirm these small caps destroy 2layers of steel Kevlar gloves."

In direct contact? If not, at what kind of distance?

As to my first post, you can use mineral wool if you like to mittigate the danger of delayed detonation due to burning wool (i.e. the e-match being removed away from the primary filling by accident, igniting the wool but not the primary). Also, mark the the height of the tube on your e-match leads so you can confirm that the e-match is making contact with the primary. .

Also, have a tried method for attaching a string to your blasting cap. That way you can topple your charge and pull out the blasting cap from safe distance (30 m) in case of mis-fire.
"I use better principle: Keep your the thinks away from HMTD and TATP"

this principle applies to all primary explosives - lead azide, clathrates, acetylides...

You need a face shiled (use 3 layers of plastic - buy 3 face shields and join them). Kevlar/steel gloves or leather gloves (wear 2 pairs at the same time), several layers of kevlar sleeves. ear plugs + ear muffs and serious body protection. Use serious bucket cover when working with metal tubes.
Also, use two trees to shield you from accidental blast when connecting the leads to your main loine or RF terminal - like this:


[Edited on 21-3-2019 by Rocinante]

Attachment: phpi1REt9 (21kB)
This file has been downloaded 770 times


XeonTheMGPony - 21-3-2019 at 15:25

Quote: Originally posted by MineMan  
I just don’t get how the primary does not fall out of the paper tube...

Anyways. With NiGKCLO4. I think one can just have 100mg of primary in a 2-3mm THIN Al tube. 100mg of 32GPa should do almost everything. You only need to press one time. Just FYI. Test confirm these small caps destroy 2layers of steel Kevlar gloves. They dent a quarter too.

Just put it in a vice. And bingo. I thinks that’s the easiest safest way... if it goes you don’t have copper pieces that I have witnessed going through a steel cooking pot!


Pressure lots and lots and lots of pressure, I have yet needed to use a binder but if one must there is a great deal to chose from.

Every thing starts at the ematch! So I'll start here

First pick is the lay out, the Nitro lacquer is at a runny viscosity so it will coat and excess will drip off leaving a nice film.

The Wire is 30 AWG NiChrome, the distance I have the lead wire set to will make a rather predictable 1.5Ohm +- .3ohm

this is dipped in the Nitro Lacquer, then dipped into the primary of choice, in this case it is lead styphnate

After which the first dip has fully dried continuity is checked by multimeter, if passed it then gets a second dip.

After it has fully dried it is again checked and dipped a 3rd time.

This does several things, it primes the wire with a pyrotechnical mix, it glues every thing together rock solid and protects the bridge wire during handling.

After fully dried it is again checked for resistance and shape.




[Edited on 22-3-2019 by XeonTheMGPony]

Set up.jpg - 186kB 1.5ohm bridge wire.jpg - 255kB Primed wire.jpg - 309kB Nitro lacquer dip 2.jpg - 404kB NL dip 3.jpg - 366kB

This makes a very reliable and safe e-match that is quite durable and offers extremely reliable ignition as on firing you get flaming bits of nitro cellulose shooting every where with a strong shock pulse from the Lead Styphnate.

Normally I mix the primary in with a thinner mix of Nitro Lacquer, but I need more wide mouth bottles to do it this way. When that is don it gets 3 primary dips, then 2 thicker Nitro Lacquer dips to seal and protect.

[Edited on 22-3-2019 by XeonTheMGPony]

twelti - 23-3-2019 at 12:02

Quote: Originally posted by Laboratory of Liptakov  
CHP is possible mixed in any ratio with ETN. For example 80:20 or 50 :50 or 25: 75. Results in solid cavity is always same. Full detonation. Even 20 % of CHP can force full detonation on ETN. But only in solid cavity. Most easy for filling detronators is ration 50:50. For all segments. For hogh pressed output segment and also for starting segments.

If the CHP is very good, what is the advantage of adding ETN?

twelti - 23-3-2019 at 12:05

Quote: Originally posted by underground  
You can also construct an EBW device for safe detonations. Use the search engine and you will find lots of information.I am planning to built one in the near future, i will post it on SM then i will finish it.

[Edited on 20-3-2019 by underground]

I am very interested in that. i saw one one youtube (https://www.youtube.com/watch?v=o4KuD-c_gRY)
where he made a simple EBW and detonated ETN. It is ia bit dangerous in a different way, but maybe more predictable is you are well versed in electrical engineering.

twelti - 23-3-2019 at 12:11

Quote: Originally posted by underground  
You can also construct an EBW device for safe detonations. Use the search engine and you will find lots of information.I am planning to built one in the near future, i will post it on SM then i will finish it.

[Edited on 20-3-2019 by underground]

I am very interested in that. i saw one one youtube (https://www.youtube.com/watch?v=o4KuD-c_gRY)
where he made a simple EBW and detonated ETN. It is ia bit dangerous in a different way, but maybe more predictable is you are well versed in electrical engineering.

Laboratory of Liptakov - 23-3-2019 at 12:33

Quote: Originally posted by twelti  
Quote: Originally posted by Laboratory of Liptakov  
CHP is possible mixed in any ratio with ETN. For example 80:20 or 50 :50 or 25: 75. Results in solid cavity is always same. Full detonation. Even 20 % of CHP can force full detonation on ETN. But only in solid cavity. Most easy for filling detronators is ration 50:50. For all segments. For hogh pressed output segment and also for starting segments.

If the CHP is very good, what is the advantage of adding ETN?


Because ETN and PETN has better brizancion than CHP. For detonators is brizancion and initiation mightiness main parameter always.

MineMan - 23-3-2019 at 14:40

Yes Xeon. Right up against the gloves. 75mg blows through 2 layers...

For the ematch why not dip it in nitrocellulose and primary mix? Say 15NC 70NiAgKCLO4, 15 Ammonium perchlorate.

XeonTheMGPony - 23-3-2019 at 15:38

Quote: Originally posted by MineMan  
Yes Xeon. Right up against the gloves. 75mg blows through 2 layers...

For the ematch why not dip it in nitrocellulose and primary mix? Say 15NC 70NiAgKCLO4, 15 Ammonium perchlorate.


that's exactly what is don, first dip is that, second and third are re-enforcing coatings to immobilize the bridge wire and prevent damage for hard packed dets

Only mine is Lead styphnate befor that was Mercury fulminate

https://www.google.com/url?sa=t&rct=j&q=&esrc=s&...

[Edited on 23-3-2019 by XeonTheMGPony]

FeedMe94 - 26-3-2019 at 23:54

I want to use my det caps as boosters too. Will this do the job ? 0.7 cast ETN, 0.3 hand pressed ETN and 100mg SADS

XeonTheMGPony - 27-3-2019 at 03:37

I've never bothered to cast, just press the ETN and go. but that should work.

[Edited on 27-3-2019 by XeonTheMGPony]

Herr Haber - 27-3-2019 at 04:30

Quote: Originally posted by FeedMe94  
I want to use my det caps as boosters too. Will this do the job ? 0.7 cast ETN, 0.3 hand pressed ETN and 100mg SADS


That'll do the job just fine.
I suppose some people would say that 100mg SADS is overkill but... why be cheap ?
I thought hand pressed on top of melt cast ETN was a good idea until I saw some tests where loose ETN failed to initiate while melt cast did initiate with the same amount of primary. These tests stand against every other publication on the subject, stand against common sense and intuition too so dont take my word for it.

Rocinante - 27-3-2019 at 12:26

Hand pressed ETN goes easily to 0.85 g/cm3 and hence about 70 kbar. 1 g of 70 kbar material will initiate anything that will detonate just from a blasting cap, provided that the BC material is not more than 3 mm thick in case of plastic or 1 mm in case of aluminium.
Extra high densities (pressing, melting) are just a game- Sure, it is nice - it saves material and it might - from time to time - mean a success where u'd fail with hand pressed ETN.... but that is rare

Press it inside a blast mittigation device - like my bucket and wear protection.

XeonTheMGPony - 27-3-2019 at 18:33

3mm steel plate.
1g hand pressed ETN
0.5g Mercury fulminate/ Potassium Chlorate 80/20
a dash of lead styphnate as a flame catcher (I've used Nitro Cotton in the past for this function)

Tube is sealed with glue impregnated tissue paper, then above that is crimped when the glue has set.

20190327_201048.jpg - 2.1MB

7mm OD 6.5mm ID, by 50mm length, 4.8 grams total assembly weight. End is sealed with a drip of Nitro Lacquer

20190327_195625.jpg - 197kB

[Edited on 28-3-2019 by XeonTheMGPony]

FeedMe94 - 27-3-2019 at 22:21

Good looking detonator and works perfect. Is it arduino sensor casing ?

FeedMe94 - 27-3-2019 at 22:27

Quote: Originally posted by Rocinante  
Hand pressed ETN goes easily to 0.85 g/cm3 and hence about 70 kbar. 1 g of 70 kbar material will initiate anything that will detonate just from a blasting cap, provided that the BC material is not more than 3 mm thick in case of plastic or 1 mm in case of aluminium.
Extra high densities (pressing, melting) are just a game- Sure, it is nice - it saves material and it might - from time to time - mean a success where u'd fail with hand pressed ETN.... but that is rare

Press it inside a blast mittigation device - like my bucket and wear protection.


Thank you for the info. Will it be better to add some PETN at the bottom and then some hand pressed ETN ?
Also whats a blast mittigation device?

FeedMe94 - 27-3-2019 at 22:35

Wiki says that density of ETN is 1.72g / cm3 and
PETN 1.77g/cm3. That means i can fill 1.5g per cm3 easily ?

underground - 28-3-2019 at 00:53

Quote: Originally posted by FeedMe94  
Wiki says that density of ETN is 1.72g / cm3 and
PETN 1.77g/cm3. That means i can fill 1.5g per cm3 easily ?


Yea

markx - 28-3-2019 at 01:25

Quote: Originally posted by FeedMe94  
Wiki says that density of ETN is 1.72g / cm3 and
PETN 1.77g/cm3. That means i can fill 1.5g per cm3 easily ?


Not easily and please DO NOT start forcing it! The density values stated in Wiki are pretty much the maximum that can be achieved and to reach them an enormous pressing force has to be applied.
Shooting for 1,0-1,3g/cm3 is excellent for starters, as far as any practical purposes are concerned.

Keep safe!

FeedMe94 - 28-3-2019 at 02:35

Thank you for that info. My casings are 6*50mm. For primary i have SADS and secondary i have ETN and PETN. Any advices or tips for how to do it ?
My fuse is visco

CHP - ETN

Laboratory of Liptakov - 28-3-2019 at 02:47

According this test is possible go to on density 1,7 g/cc in the vise. Enormous pressing force was 150 - 200 Kg in described cavity.
For hand pressing was use about 30 - 40 Kg on density 1,3 g/cc.
Others values in the pictures.....:cool:...LL

pressed Berta1.jpg - 342kB

profile test ETN.jpg - 1.2MB

XeonTheMGPony - 28-3-2019 at 03:39

Quote: Originally posted by FeedMe94  
Good looking detonator and works perfect. Is it arduino sensor casing ?


7mm chromed brass hobby tube, it is hard to find where I moved to, so am running out, but on AliExpress I found thermal wells that are near identical but better. they're sealed at the end and stainless steel

Can make nice commercial quality hermetically sealed dets.

Herr Haber - 28-3-2019 at 04:15

How many manipulations with your hands close to the det when you:

- Melt cast ETN
- Pour and press repeatedly

So no, it's not just a game. Obviously there is less danger if you boil a glass of water and suspend your det in in that ramming powder in increments.



MineMan - 28-3-2019 at 08:08

Hey. What kind of glue to you all use to seal your caps?? I bought like 4 different kinds. My goal was to find a thick clear gel glue that would dry rubbery like a glue gun. I would use a glue gun but it dries before it goes below the fuse.

XeonTheMGPony - 28-3-2019 at 18:38

https://www.ebay.ca/itm/5-pcs-OD-6mm-OD-7mm-OD-8mm-SS304-The...

I use a good quality wood glue, no need to go all fancy. Weld bond is a good one.

I all so used 2 part epoxy for the ones I intended for under water stuff, using sand as a filler, after it is set I crimped to comperes seal it on top of the epoxy bond.

For the lower seal (Providing you care fully test for comparability) is Tissue paper and super glue for a fast seal, then a wood glue on top of it.

Other wise epoxy is a solid go to.

[Edited on 29-3-2019 by XeonTheMGPony]

XeonTheMGPony - 31-3-2019 at 10:40

Ok I fabricated a simple primary pellet press to demonstrate.

When the pellet is placed over the base charge is when the cap is truly armed

20190331_112915.jpg - 408kB 20190331_112936.jpg - 255kB 20190331_112925.jpg - 299kB 20190331_121356.jpg - 325kB 20190331_121421.jpg - 216kB

Bore is 5mm deep by 4.5mm od, with the ejection pin it is 4.5mm deep.

The ID of the paper cartridge is 4mm, and will hold 200mg of Mercury fulminate/chlorate mix, and is made with standard printer paper.

A small bit of parchment paper can make a end cap on the under side (Ejection pin surface)

[Edited on 31-3-2019 by XeonTheMGPony]

Laboratory of Liptakov - 1-4-2019 at 01:17

When I see fulminate and its pressing, my hair gets up in horror. Well, what. We all need our dose of adrenaline.....:D...LL

Herr Haber - 1-4-2019 at 03:20

Very nice Xeon !
The pellet looks very sturdy. Any idea on the pressure applied ? Did you use a binder ?

XeonTheMGPony - 1-4-2019 at 04:26

It is bound in the paper tube, I hand pres lightly then do a final tamp with a hammer and machined pressing mandrel, few taps safely compresses it down solidly (Holding the mandrel remotely so fingers are not over it), no binders. You must use at minimum 2 layers of paper on the side to facilitate safe ejection

It is carefully cleaned between each operation to remove any lose primary from every part of it!

it is quite safe, even if it goes off the mandrel will be shot away with moderate force and you get confetti (Risk goes up as less paper is used) mind you I have yet to ever have it go off on me (Know what your primaries do, test test and test some more befor doing any thing with them)

An Arbour press is better but yet to get one, it is all so much safer with a proper press as one operation has much lower risk of one going off then multiple pressing operations.

So first press all your base charges, then press your primary pellets, then when ready those are pressed over the base charge and continue down the line

tools needed to make such a thing?, 2 drill bits, A drill press, 2 quality nails, a file, a drill, patience, and a fairly accurate means to measure.

Drill the guide hole as to accommodate the nails shaft that allows smooth movement, in the drill file down the head to a tight fit inside your chosen tube id, and find a matching drill bit. make a means to limit the depth of the drill bore for this larger diameter, and make a second drill hole. Smooth out all edges high grit count sand paper does this nicely. File a matching nail to the ID of the paper carrier shell and don (Again ensure this is nicely smoothed as well sharp edges are risks.

Brass is the best body material due to non sparking nature and is self lubricating to a degree but steel can be used, just implement more precautionary measures.

[Edited on 1-4-2019 by XeonTheMGPony]

markx - 1-4-2019 at 05:54

Quote: Originally posted by XeonTheMGPony  
It is bound in the paper tube, I hand pres lightly then do a final tamp with a hammer and machined pressing mandrel, few taps safely compresses it down solidly (Holding the mandrel remotely so fingers are not over it), no binders. You must use at minimum 2 layers of paper on the side to facilitate safe ejection

It is carefully cleaned between each operation to remove any lose primary from every part of it!

it is quite safe, even if it goes off the mandrel will be shot away with moderate force and you get confetti (Risk goes up as less paper is used) mind you I have yet to ever have it go off on me (Know what your primaries do, test test and test some more befor doing any thing with them)

An Arbour press is better but yet to get one, it is all so much safer with a proper press as one operation has much lower risk of one going off then multiple pressing operations.

So first press all your base charges, then press your primary pellets, then when ready those are pressed over the base charge and continue down the line

tools needed to make such a thing?, 2 drill bits, A drill press, 2 quality nails, a file, a drill, patience, and a fairly accurate means to measure.

Drill the guide hole as to accommodate the nails shaft that allows smooth movement, in the drill file down the head to a tight fit inside your chosen tube id, and find a matching drill bit. make a means to limit the depth of the drill bore for this larger diameter, and make a second drill hole. Smooth out all edges high grit count sand paper does this nicely. File a matching nail to the ID of the paper carrier shell and don (Again ensure this is nicely smoothed as well sharp edges are risks.

Brass is the best body material due to non sparking nature and is self lubricating to a degree but steel can be used, just implement more precautionary measures.

[Edited on 1-4-2019 by XeonTheMGPony]


Christ on a cross!! Hammering on primaries is really the last "best practices" approach that should be advertised publicly. Shock loads are the worst kind of danger factor, even when supposedly dosed in a gentle manner. I'm sure you know your limits and the substances, but someone less experienced may not and such practice should not be advocated as a viable approach regarding the topic at hand.
One can easily build a simple lever pressing device....out of wood for example. It takes no more than a saw, some drill bits, couple of bolts and screws. And it can be adequately shielded by simple means. Something that is very unlikely to be achieved with the "tapping" method.

Laboratory of Liptakov - 1-4-2019 at 07:43

My opinion is, using instead all metal parts hard wood. For example from the Beech. And using 2% oil + 2 % PIB as binder....:cool:...LL

twelti - 2-4-2019 at 08:05

Quote: Originally posted by XeonTheMGPony  
Ok I fabricated a simple primary pellet press to demonstrate.

[Edited on 31-3-2019 by XeonTheMGPony]


How does this pellet system work, I am not familiar. maybe a sketch?

[Edited on 2-4-2019 by twelti]

[Edited on 2-4-2019 by twelti]

Laboratory of Liptakov - 2-4-2019 at 10:38

Because pellet is preesed, create solid one part. This is advantage for next manipulation, inserting to cavity with low danger exces.

FeedMe94 - 5-4-2019 at 07:26

My det casings are 6mm x 50mm. Today i detonated 0.8 PETN with 60mg SADS. The second test failed and a friend told me about critical diameter of PETN which is 9mm. If thats true how did the first detonator went off ?

https://ibb.co/gJ18FnS
https://ibb.co/4ShDxLr

Laboratory of Liptakov - 5-4-2019 at 07:55

Whats the question? Critical diameter (minimal diameter of a rod that can sustain detonation propagation): 0.9 mm for PETN at 1 g/cm3, smaller for higher densities (other value: 1.5 mm)
https://en.wikipedia.org/wiki/Pentaerythritol_tetranitrate

FeedMe94 - 5-4-2019 at 08:06

Sorry but my English are not good. Critical diameter is the lowest diameter of the detonator case that will allow PETN to explode , right ? My case is 6mm and still detonated

MineMan - 5-4-2019 at 20:52

Quote: Originally posted by FeedMe94  
My det casings are 6mm x 50mm. Today i detonated 0.8 PETN with 60mg SADS. The second test failed and a friend told me about critical diameter of PETN which is 9mm. If thats true how did the first detonator went off ?

https://ibb.co/gJ18FnS
https://ibb.co/4ShDxLr



Your friend is wrong. Industrial detonators use PETN in 6mm!!! PETN works in detcord which is 2mm. You need more or a better primary.

FeedMe94 - 5-4-2019 at 23:04

Quote: Originally posted by MineMan  


Your friend is wrong. Industrial detonators use PETN in 6mm!!! PETN works in detcord which is 2mm. You need more or a better primary.


I thought SADS was a good primary. At the moment i can only have TATP and SADS

Rocinante - 6-4-2019 at 13:05

just use more, at least 170 mg
be warned, tho... SA.DS does degrade if not well sealed and isolated (10 days+)
SA.DS will degrade from direct contact with PETN, esp. not recrystalzed... the remains of sulfuric acid will convert the surface of SA.DS....

Laboratory of Liptakov - 6-4-2019 at 13:19

SA.DS is best primary between classic materials. But is weak. Has 3460 m/s at best density. Is it not some great. Lead azide has 5200m/s. And commerce filling is 300 mg. Therefore your det. device are no-reliable with 0,06 SA.DS. Thats clear...:cool:...LL

XeonTheMGPony - 7-4-2019 at 13:05

Quote: Originally posted by Laboratory of Liptakov  
SA.DS is best primary between classic materials. But is weak. Has 3460 m/s at best density. Is it not some great. Lead azide has 5200m/s. And commerce filling is 300 mg. Therefore your det. device are no-reliable with 0,06 SA.DS. Thats clear...:cool:...LL


Commercial is an 80% Lead Azide and 20% Lead Styphnate

In a re-enforcing cap pressed it can be as low 100mg.

But for some one new with out much practical experience best never go below 300mg of primary till you develop some basic tooling.

Laboratory of Liptakov - 7-4-2019 at 13:18

My word, same opinion. On amateur field with amateur cavity is better always use 300 mg for any primary compound.

MineMan - 7-4-2019 at 15:10

Did you follow the correct procedure for SADS?! Preparation effects power. Mix 20 percent PP in. Should only need 50-100mg. Make sure you have 100mg of loose PETN on top of your pressed PETN. SADS will do fine. Is your product white as snow? Because mine DDTs in under a mg.

Make sure you read the section in Primary Explosives.... synthesis temp is VERY important.

Also. Why not just make CHP or TACP with glycine??

FeedMe94 - 7-4-2019 at 21:08

Is not pure white but detonates unconfined even at 1mg. Cannot make CHP or TACP cause i don't have AP

Herr Haber - 8-4-2019 at 08:04

300 mg ?!

When ETN / PETN is initiated by as low as 20mg that seems like massive overkill.
Ok, 20mg is not practical because it's to small and or / might mix with your secondary if not correctly pressed.
But 300 ?

twelti - 8-4-2019 at 08:12

Regarding pressing of either primary or secondary, is it not possible to press it slightly wet, and then include some desiccant inside the (sealed on both ends) det cavity? Seal, crimp, or whatever, and let the energetics dry internally?

Second: Does anyone know if there are incompatibility with epoxy glues and SADS or ETN/PETN? Seems like I read some story about someone who left out some epoxy with peroxide ini it and his dog stepped on it. Yikes!

XeonTheMGPony - 8-4-2019 at 14:22

Quote: Originally posted by Herr Haber  
300 mg ?!

When ETN / PETN is initiated by as low as 20mg that seems like massive overkill.
Ok, 20mg is not practical because it's to small and or / might mix with your secondary if not correctly pressed.
But 300 ?


For some one just starting it is better to go massive over kill to ensure full initiation, Vs some one ending up with a live fissled cap sitting on top of a main charge!

As they gain practical experience they can start going smaller as they learn the art n science of dets.

Laboratory of Liptakov - 8-4-2019 at 21:17

Xeon says wise words. For beginners is better bigger cap-charges with lower density. And step by step, with bigger experiences and quality cavity and tools is possible go to on on smaller det. cap with high density.

Herr Haber - 9-4-2019 at 03:26

You are both of course absolutely right :)

Thank you for reminding me that this can happen.

FeedMe94 - 9-4-2019 at 05:49

You are both absolutely right , like Herr said. As always !!
Science madness is the best school i could ever attend

C6(NO2)5CH2CH(CH3)N(NO2)2 - 9-4-2019 at 15:18

Quote: Originally posted by twelti  
Second: Does anyone know if there are incompatibility with epoxy glues and SADS or ETN/PETN? Seems like I read some story about someone who left out some epoxy with peroxide ini it and his dog stepped on it. Yikes!


I've read that story too. It wasn't completely clear whether the epoxy reacted and made the compound more sensitive, or if it was just a mechanical effect of holding it together in a brittle block. peroxides are pretty sensitive already. As far as nitrates and acetylides are concerned, that's a really good question-that I don't know the answer to.

https://www.thevespiary.org/rhodium/Rhodium/www.roguesci.org...

Incidentally, Does anyone know if that archive is a complete copy of the roguesci forum, or are there other threads that did not get incorporated into the mirror?


tubes

twelti - 14-4-2019 at 14:36

So, I think I understand the reasoning for metal tubes. Protection of the inside, and possibly confinement for some materials. Aside from the confinement issue, I'm guessing that commercial dets must use sturdy metal tubes since they never know what handling there may be in the field - transportation, construction sites, etc. BUT for me, I only need to make it from my basement to the back yard (or in the near future to a bucket on sawdust IN my garage - a la Liptakov). In an extremely controlled environment like that, is there any advantage to metal tube? Does the confinement around the sides, together with minimal confinement on the business end add to the initiating power?

Laboratory of Liptakov - 14-4-2019 at 22:39

With the exception of shrapnel, the solid cavity contributes positively to all necessary parameters for the detonator. Reliability, durability, easy filling and so on.....:cool:...LL

berta on 4mm.jpg - 588kB

Herr Haber - 15-4-2019 at 05:37

@Twelti: Factors affecting the efficiency of detonators.
Get that pdf from the library. It was truly an eye opener for me. This should help you answer some of your questions.

twelti - 15-4-2019 at 11:18

Quote: Originally posted by Herr Haber  
@Twelti: Factors affecting the efficiency of detonators.
Get that pdf from the library. It was truly an eye opener for me. This should help you answer some of your questions.


Very useful, thanks. i wonder if it can answer the question: is a smaller metal tube det more or less safe as a larger less confined det of same initiating power? I'm sure that depends on many other factors.

Herr Haber - 16-4-2019 at 04:35

I'd say that with a smaller tube you'll make a more efficient detonator that what you'd do in a larger tube with less confinement and lesser density.

If it's less dense it's VOD will be lesser and will probably be "safer" to handle if things go wrong.

MineMan - 16-4-2019 at 23:22

Industry detonators are thin Al tubes. With a steel sleeve surrounding the primary. Ideally. Very thin tubes are wanted as we want energy going into the explosive not accelerating the case/tube. But for DDT strong tubes are usually needed. However I have had success in a carbon fiber arrow tube. But the ddt formula for that is complex.

FeedMe94 - 17-4-2019 at 00:49

I made a small detonator with 300mg recrystalized ETN slightly press inside a plastic 2ml tube. The rest was filled with al foil and ignited by visco fuse. It sounded like it detonated but im not sure if it went full order.


Laboratory of Liptakov - 17-4-2019 at 01:54

For measurement of brisance of any amateur detonator, is steel plate base condition. Usually 1 - 2 mm of thickness. It give clear result. Wood cavity is nonsense.

FeedMe94 - 17-4-2019 at 05:56

Quote: Originally posted by Laboratory of Liptakov  
For measurement of brisance of any amateur detonator, is steel plate base condition. Usually 1 - 2 mm of thickness. It give clear result. Wood cavity is nonsense.


You are right i just didnt have something to test on. I just tested 500mg ETN and 500mg ETN + 150mg SADS on 2mm steel. Non of them penetrated it.
1) ETN wasnt pressed
2) The centrifuge plastic tube have round bottom so it didnt make full contact on metal

I will get 1mm steel plate and also i will melt the bottom of the plastic tube to make it flat and i will repeat the test

Lead block measurement

Laboratory of Liptakov - 17-4-2019 at 11:17

Much better is Lead block. You can use repeately. All energy is discharged into material, without loss in some hole. In metal plate is usually hole. In Lead block not. Crater give an clear result about all energy from destruction device. Almost entire energy is catched in lead. And is it pretty nice. As some crater on the Moon.

lead.JPG - 477kB

For example, at same conditions (500 mg output segment) has CHP smaller brizancion than ETN. But CHP is not molecular explosive. Only salt + Fuel. CHP not require some next primary mixture for reliable start. Works as primary and secondary as 2 in 1.


CHP lead.JPG - 516kB

[Edited on 17-4-2019 by Laboratory of Liptakov]

Laboratory of Liptakov - 23-4-2019 at 09:20

Next serie of tests show different properties of tested materials and his mixtures. Weak is mixture TACP/ glycine from recrystall process.
Tests on the lead block show an clear difference. If used steel plate, is difficulty find a clear difference between samples. Highest energy has of course pure ETN (above) . Follows....... ETN/CHP......CHP....... CGP. Values in mm/grams.....:cool:...LL

test impact.JPG - 501kB

MineMan - 23-4-2019 at 22:42

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

FeedMe94 - 23-4-2019 at 23:10

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.


Wow , i didn't know that. I have PENT and atomized Al. I will try it soon

MineMan - 23-4-2019 at 23:43

Quote: Originally posted by FeedMe94  
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.


Wow , i didn't know that. I have PENT and atomized Al. I will try it soon


Yes. It’s a big deal for advancement of laser detonators. Let us know your results. 5% Al is the prescription. I believe the paper was in EPP a few months ago...

I don’t know optics well enough to focus a laser after fiber optic cable though...

A single mode diode can focus the smallest. Best bet would be the 900mw 405nm singlemode didoe.

Laboratory of Liptakov - 24-4-2019 at 01:10

Optical cable inserted instead fuse? Maybe is time buy some laser......:D...LL

MineMan - 24-4-2019 at 12:02

Quote: Originally posted by Laboratory of Liptakov  
Optical cable inserted instead fuse? Maybe is time buy some laser......:D...LL


Correct LL. Fiber optic cable insstead of fuse or wire!

twelti - 24-4-2019 at 12:09

Quote: Originally posted by MineMan  
Quote: Originally posted by Laboratory of Liptakov  
Optical cable inserted instead fuse? Maybe is time buy some laser......:D...LL


Correct LL. Fiber optic cable insstead of fuse or wire!


I wonder if a beam expander (which actually help focus to a small spot at a distance) and a higher power laser would work at moderate distances without the FO cable? I have a 1 watt blue laser that I have used many times to set off small charges of AP from about 8 feet.

MineMan - 24-4-2019 at 20:36

Quote: Originally posted by twelti  
Quote: Originally posted by MineMan  
Quote: Originally posted by Laboratory of Liptakov  
Optical cable inserted instead fuse? Maybe is time buy some laser......:D...LL


Correct LL. Fiber optic cable insstead of fuse or wire!


I wonder if a beam expander (which actually help focus to a small spot at a distance) and a higher power laser would work at moderate distances without the FO cable? I have a 1 watt blue laser that I have used many times to set off small charges of AP from about 8 feet.


My guess is for detonation is must be very small. Let me look up the paper.

deadpool - 30-11-2019 at 13:32

Hello,

This is a question for XeonTheMGPony, have you tried using commercial primers for caps instead of re-inventing the wheel? Don't get me wrong, you have done a great job, but I wonder if a normal primer could be adapted to be used electrically for your caps?

Why not reinvent the wheel?

wessonsmith - 30-11-2019 at 14:00

My det caps are both safe to load and have zero shrapnel risk. Yes, I needed to reinvent the wheel, but that's the fun of it.

https://drive.google.com/open?id=1d0D9WVLlj-MpjEukyICJDtty6C...

[Edited on 30-11-2019 by wessonsmith]

XeonTheMGPony - 1-12-2019 at 19:12

Quote: Originally posted by deadpool  
Hello,

This is a question for XeonTheMGPony, have you tried using commercial primers for caps instead of re-inventing the wheel? Don't get me wrong, you have done a great job, but I wonder if a normal primer could be adapted to be used electrically for your caps?


what do you mean by primer? Atm I use all industry standard systems.

I just make them my self as due to the idiocy of our laws here.

Mine are perfectly safe as well, you have to be rather spectacularly stupid to injure your self with one, IE safety is in the person not the substance

[Edited on 2-12-2019 by XeonTheMGPony]

orbitalchemtech - 15-10-2020 at 18:50

Quote: Originally posted by XeonTheMGPony  
Why re-invent the wheel, industry standard practices, over 60,000,000 million made a year with very few if any defective units or detonations unintended.

Do research, pick a form factor, make some basic tools and be don with it.

I use two standard of tubing, 7mm od 6.5mm ID or 6mm Od, and 5.5 ID

I get high quality nails, then lath them down to the size of the tube then a hair more to allow clearance and that has a paper spacer to ensure the metal never makes contact to the tube.

Base charge is pressed in, primary charge is pressed into a solid paper tube that firmly fits in the tube, so on.

Very safe, very reliable, very simple, and each stage can be don on mass.

What gets you in danger is changing things up all the time, not having a solid system in place, and good job specific tooling, it doesn't need to be fancy or high tech, it just need be made for the task at hand


A pneumatic cylinder works well for a press and can be activated remotely so there is no danger from pressing operations and with added blast shields if an accident occurs shrapnel is directed in a safe direction. Tooling is easily made from some wood and dowels and pressure can be adjusted with regulator to get desired force I think pressing anything by hand is risky business


20201015_074330.jpg - 3.3MB20201015_074346.jpg - 3.1MB

Hey Buddy - 18-11-2020 at 07:14

I'm new on sm but something I've noticed that isn't common here but is the standard in mds demolition is the use of dual priming. There is basically no scenario where a charge would not be primed with dual caps for a blast. Even on command dets and time delay, engineers always use two caps for redundancy. If one cap fails the second fire succeeds assuming known components are being used. I should mention that the use of dual caps can be tricky in situations with Shocktube. Ive seen a dual prime using a Shocktube primary detonator cap and a fused secondary cap. If the time fuze is lit and the shocktube isn't detonated before the time fuze runs out, the detonation will travel backwards up the shocktube and detonate the primer initiator in the wrong direction, injuring the user. I dont think ppl here are making shock tube but I thought it was worth mentioning as I saw it happen in demolition and it really confused everyone when it occured.

Pyro_cat - 8-2-2021 at 18:08

Still way to scaredy-cat to think about packing a primary in a metal tube.

How about filling it with primary wile its still wet then adding a drying agent of some sort on top to pull the water out after you are all done ?

Suppose the water could make some primaries react with the tube.

Just an idea I thought of, I am not doing it.

ManyInterests - 20-10-2021 at 00:01

I wish I was here last year, as WessonSmith is gone and his google drive links are now dead.

But that being said, I need to ask about strategies to load a blasting cap without any special equipment. I plan on using the body of a ballpoint pen (one end sealed with hot glue) and use either picric acid or ETN as the secondary with NHN as the primary, topping it with black powder as the igniter and setting it off with an electric match.

My electric match design is a bit different than most people here. I use regular match (or two if I can fit it in the cap) and wrap the matchheads with 0.1mm or 0.08mm nichrome wire. I've built dozens of them for practice and they all reliably fired up.

The reason why I want to use a plastic pen body is A: It's easier and quicker to get than a metal tube, B: it's chemically inert, so I don't have to worry about the energetics reacting in any way that would destabilize the thing. C: because it's transparent, I can see how everything looks on the inside.

My biggest fear right now is how to press everything without it exploding. Normally I prefer to find a video of something like this before going forward. While I've been able to find plenty of video from chemistry YouTubers going into great detail on how everything works. The actual construction of a blasting cap is reduced to one Indian fellow making one out of cardboard... and pressing everything by hand. The video had him use mercury fulminate as the primary. I have no access to that and I would not dare use any. Let alone do the pressing with my bare hands.

I looked through the improvised munitions handbook and what I saw there is making a wooden apparatus for press the cap, but there is no way I can construct that.

I suppose if I spent more money on electrical components I can built an Arduino operated arm to remotely do the pressing, but I don't know exactly how much pressure I need to do. Laboratory of Liptakov had a picture posted in a different thread that showed ETN pressed at 100 kg and then another charge at 1 kg. I don't know how that is in practice.

I apologize for being so verbose or coming off as intense. But I find this really fascinating and I really want to do this, but I also don't want to lose any fingers/hands and cause alarm with an inappropriate bang.

Brightthermite - 20-10-2021 at 11:47

I cant speak for picric acid but your totally good to hand press ETN. In fact the guy your referring too use to have a video up of him hand pressing his ETN/NHN caps and pounding on them using a hammer and wooden dowel.

Hand press the ETN and dump some NHN on top and as long as its sealed up well it should detonate fine. I never press my caps much and they perform fine. That being said, ETN pressed to 100kg with pressed NHN would perform much better but...

If your still wanting to achieve high loading pressures look into getting something like an Arbor press. Purchase a bit of sheet metal to fabricate a shield and you should be good to go.

You said your fear was the caps exploding, you should try to build a system where you'd have no problem smacking caps inside and setting them off initially. Make it safe enough that it wont be a problem

[Edited on 20-10-2021 by Brightthermite]

ManyInterests - 20-10-2021 at 13:29

Quote: Originally posted by Brightthermite  
I cant speak for picric acid but your totally good to hand press ETN. In fact the guy your referring too use to have a video up of him hand pressing his ETN/NHN caps and pounding on them using a hammer and wooden dowel.

Hand press the ETN and dump some NHN on top and as long as its sealed up well it should detonate fine. I never press my caps much and they perform fine. That being said, ETN pressed to 100kg with pressed NHN would perform much better but...

If your still wanting to achieve high loading pressures look into getting something like an Arbor press. Purchase a bit of sheet metal to fabricate a shield and you should be good to go.

You said your fear was the caps exploding, you should try to build a system where you'd have no problem smacking caps inside and setting them off initially. Make it safe enough that it wont be a problem

[Edited on 20-10-2021 by Brightthermite]


The video of him handloading and pressing det caps is not up anymore. If it is up somewhere I sure cannot find it.

And no, I don't really need it to be that tightly pressed. As much as I enjoy the challenge of working around the dangers of this hobby. My end goal is just to make one or two blasting caps. A small charge, and go out in to the middle of nowhere and set them off. It's just a personal challenge to see if I can 'do' it, if you know what I mean.

I don't want to get an arbor press. It's a bit overkill for my purposes. I also really like to do some arts and crafts (my username is ManyInterests for a reason), and I think a simple hydraulic press like this will do.

https://www.youtube.com/watch?v=u7My4pUk8A4

It's childish I know, but I've seen people make those than can crack walnuts.

The other thing is that I cannot afford to have any caps go off in my apartment. I live in an apartment in a crowded area and will attract a lot of unwanted attention. I mentioned it many times in my previous posts and I just really don't want to alarm anyone while doing this.

But if you're saying that gentle hand pressing is sufficient and completely safe with ETN and the NHN on top of it (and the black powder igniter on top of that) then that is a load off my mind. I just need to do a little research to make sure that any static electricity made is neglible.

My plastic pen might be a little longer for it's purposes, but as long as it can hold the 2 to 2.5 grams of energetics it should be good. if is too long I'll trim it down afterwards before inserting my electric match and sealing the top with epoxy.

I am using very long wires (3 meters) connected to a 433 mhz remote switch module. This will allow me to setup my electronics a decent distance from detonation and the remote switch will allow me to be even further and observe in complete safety from any possible flying debris.

PlasticPen.jpg - 1.5MB

Brightthermite - 20-10-2021 at 16:48

I completely understand, I would love to have a way to press my caps to max density or melt cast them.

Once again I cant speak for the NHN but the ETN should have no trouble with static. I have loaded it in all different types of plastic and metal containers with no issue.

If your looking to keep it quiet and no shrapnel, saw dust is your friend. I have a plastic tote and a 5 gallon trash bag full of saw dust that I test caps in. There is next to no noise. Place it in the tote and cover the cap with the bag.

Laboratory of Liptakov - 20-10-2021 at 17:17

Brightthermite say truth. Sound is same a like banging of the door...:cool:

ManyInterests - 20-10-2021 at 17:33

That is very good. I was thinking of getting a 5 gallon bucket and filling it with kitty litter. I don't know where exactly to get saw dust since I never looked, but I will search for it.

Safety first, safety second, and safety third. The results will follow, but you need to be in a proper condition to report on them.

Quote:
Brightthermite say truth. Sound is same a like banging of the door...:cool:


Also, Laboratory of Liptakov, I have some questions. I saw your videos (and downloaded them!) on plasticizing things. They answered soooo many questions I had regarding making plasticized energetics.

But I got questions: Firstly when you soaked the Scapa tape in gasoline to extract the rubber, is it the same gasoline you get the from the gas station? Would lighter fluid like Zippo or ronsonol also work for that? Also you used toluene and acetone mixed in a 1:1 ratio. Would xylene work? I can get toluene, but it's much easier to get some xylene.

What do you think of using rubber cement and bar & chain oil as a plasticizer?

Laboratory of Liptakov - 21-10-2021 at 02:56

1)Is possible use any gasoline, but results will worse. Stink, aggressive additives which can decompose black carrier. Best is gasoline for cleaning, thus relatively pure heptane. From Amazon cleaning gasoline.
2) Xylene was not tested, necessary try it.
3) Rubber cement was not tested. According some comments, results are worse than with Scapa 2501. Hard consistency within a few days.
4) Chain oil was not tested. According his formula, results can be worse than with quality oil 5W40.

ManyInterests - 21-10-2021 at 19:23

Quote:
3) Rubber cement was not tested. According some comments, results are worse than with Scapa 2501. Hard consistency within a few days.
4) Chain oil was not tested. According his formula, results can be worse than with quality oil 5W40.


The rubber cement and bar and chain oil are used together. While I will agree that they are not as good. Getting the gasoline and scapa 2501 are very difficult for me while the rubber cement and bar and chain are very readily available. I guess I'll have to work with what I have.

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