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Tkuze
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Your favorite blasting cap design
Hey guys, i jusy wanted to survey what materials and how you make your favorite reliable blasting caps. Currently, .223 shells have the neck removed
with a pipe cutter and the opening is widened and sanded to make a perfect cylinder with one open end. These are used and filled with any suitable
secondary(1g) pressed. A chopstick is used to makd a slight hole in the center of the pressed material. This is covered with an improvised aluminim
cup to make no contact primaried with brass. 90mg dex-LA is added and carefully pressed, followed by 200mg orange/red Lead Styphnate. Gently, the
shape end of a chopstick is used to create a small hole in the center of the pressed primaries. A OOO stopper with a single hole is cut to the correct
size to press down on the primaryand be flush woth the top of the shell. The fuse is inzerted so it exits the bottom of the stopper and make contact
with the primaries via the hole/small open spacecreated by the chopshick. After the shell is sealed tightly and fuse in contact with primary, the fuse
is threated through a 9mm shell with priming cup removed and hole drilled out to accept the 2mm or 3 mm. The 9mm is slightly wider than the diameter
of the .223 shell and is slowly pressed over the .223 shel until sealed. Hot glue is introduced onto the 9mm top shell at the area where the fuse is
protruding and works well to keep it waterproof. What do you guys prefer? What household things can be used to make a stronger aluminim cup to hold
primaries instead of making Al foil cups?
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snooby
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For an based explosives, like ANNM, never had problems with just plastic blast caps... 300 mg Petn is just powerfull like hell, combined with some
good primary explosive. Never liked metal blast caps, dont think its really neccecery also... it just looks better.
I like to use a fuse thats dipped in kclo4/ti/dextrine slurry.. use good quality fuse. Never use low quality primarys... go for:
BNCP
LA
NiGP
Double salts of silveracetylide
Dont use peroxides
Use of leadstyphnate, dont know why since LA alone just works fine.
[Edited on 10-5-2019 by snooby]
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Tkuze
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Thanks. Small plastic centrifuge vials work well
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XeonTheMGPony
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I use a chromed brass tubes with .5 mm wall thickness, 7mm od, 6.5mm ID by 50mm long, sadly open at both ends
Base charge for these is 1gram pressed ETN, this is then capped by a paper shell made to tightly fit in the tube with the core being charged with 150
to 200mg of PVA-Lead Azide 80% and lead styphnate 20% (these are compounded as a powder and mixed thoroughly while dampened with a water alcohol
mixture, once thoroughly mixed it is dried, and agitated to form a free flowing dry powder)
This is then pressed into the tube on top of the base charge, this assembly is then dusted with some free flowing lead styphnate at which point an
ematch is inserted with a tissue paper gasket, the remaining volume of the assembly is then sealed with epoxy or wood glue saturated tissue paper.
These are then set to dry for a few days. I use these when there must be zero doubt as to initiation, for more every day things I use the same thing
but only a smaller tube 6mm OD by 5.5mm ID and base charge of 0.5g of ETN pressed, azide pellet is same as above.
Since the azide is fully encased by paper there is no risk or worry about it reacting with the copper in the brass.
[Edited on 11-5-2019 by XeonTheMGPony]
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Tkuze
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Thanks for the excellent reply! Thats a really good system. It makes sense that we both have basically settled on the same compounds. Have you tried
sealing the ends with anythimg besides paper and epoxy, because im assuming your current method is the best one possible? What type of paper is used
and do you press form it using a mandril/ other process or just use a rod to insert and shape it into the shell? Thats an intricate mixing process as
well. How do you safely peletize it? Also, how do you make your ematches and how do you configure it to make contact with priming compound? Sorry for
all the questions but i find your method genius. Have you ever been able to find aluminum shells with one end sealed that's cheap and commercially
available? I was thinking of aluminum .223 shells if they even exist. Or coating brass shells in an epoxy or plastic so its inert. Also, it would be
really nice to find the above described premade aluminum shells and use your method of peletizing to make a modular unit so you can load the primary
pelet onto the base and insert ignition system modularly and crimp when needed just like commercial and military #8 caps.
Any advice on how to make nice solid primary pelets in a thin/inert casing that you can keep independantly until ready? Also how is your PVA method
done? Same procedure as industry where 2 solutions combined dropwise with a basic solution at 60 C?
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XeonTheMGPony
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http://www.sciencemadness.org/talk/viewthread.php?tid=149681
http://www.sciencemadness.org/talk/viewthread.php?tid=146585
those threads have details.
That is how I do it, all industry standard methods.
[Edited on 11-5-2019 by XeonTheMGPony]
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Rocinante
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Inner tube 15 cm long, inner diamater 7 mm with 0.5 mm thick aluminium walls and a solid, round end filled with 350 mg of - yes, very lightly pressed
 SA.DS. The tube contains e-match and the rest is filled with mineral wool,
sealed with epoxy. The outer tube is 15 mm inner diamater, filled with about 800 mg of ETN pressed to about 0.9 g/cm3 and the top layer consists of
400 mg of relatively loose powder, so that the inner tube is in nice contact. Te outer tube is made out of solid, clear plastic about 2 mm thick. The
rest is filled with mineral wool, sealed. The upper end has a very well attached string so that it can be pulled out from a distance in case of
misfire (powdery explosives like ammonal). Also, you might want to coil the excess leads around the upper part of your blasting cap - this is done so
that you won't dirrectly pull on the e-match head inside the cap if you fall over and pull the leads away and the glue/epoxy fails.
This has the advantage that the lower part is well removed from your fingers so that you have low or no chance of accidental amputation and it (also)
means that the cap is well burried in a blast mittigation device so that any accidental explosion during assembly is completely absorbed.
Again, I see no reason to make the blasting caps that short. The extra few g of aluminium glitter in a big charge pose no additional fragmentation
threat.
This is not the best design (SA.DS is not that stable but it will last for months if well removed from other chemicals - except the match head).
However, it is a viable one. Even pure lead azide is not that stable when exposed to atmosphere and when in contact with copper leads (months -
years)..
[Edited on 11-5-2019 by Rocinante]
[Edited on 11-5-2019 by Rocinante]
[Edited on 11-5-2019 by Rocinante]
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imp
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.22 Win Mag empties are perfect, approximating very closely the physical dimensions of commercial fuse-type caps.
A water slurry of the chosen fill material, very little excess water, picked up via an eyedropper, the cartridge filled almost full, a plastic ram
positioned in the bench vise with the case horizontal, compresses the material down to approximately the volume found commercially in a #6 cap,
applying 20 lb-ft to the vise screw, yields ~ 3000 psi.
Let her dry, then let her rip! Dropped into the heavy steel drum of my cement mixer, shrapnel pierced tiny holes through the wall!
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MineMan
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Quote: Originally posted by imp  | .22 Win Mag empties are perfect, approximating very closely the physical dimensions of commercial fuse-type caps.
A water slurry of the chosen fill material, very little excess water, picked up via an eyedropper, the cartridge filled almost full, a plastic ram
positioned in the bench vise with the case horizontal, compresses the material down to approximately the volume found commercially in a #6 cap,
applying 20 lb-ft to the vise screw, yields ~ 3000 psi.
Let her dry, then let her rip! Dropped into the heavy steel drum of my cement mixer, shrapnel pierced tiny holes through the wall!
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Really. Shrapnel from a 22mag piercing asteel drum!! What do you fill them with?
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Tsjerk
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| Quote: Originally posted by MineMan | | Quote: Originally posted by imp | .22 Win Mag empties are perfect, approximating very closely the physical dimensions of commercial fuse-type caps.
A water slurry of the chosen fill material, very little excess water, picked up via an eyedropper, the cartridge filled almost full, a plastic ram
positioned in the bench vise with the case horizontal, compresses the material down to approximately the volume found commercially in a #6 cap,
applying 20 lb-ft to the vise screw, yields ~ 3000 psi.
Let her dry, then let her rip! Dropped into the heavy steel drum of my cement mixer, shrapnel pierced tiny holes through the wall!
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Really. Shrapnel from a 22mag piercing asteel drum!! What do you fill them with? |
Another question is; why would you want a blasting cap to produce shrapnel in the first place? I always used drinking straws filled with lightly
pressed PETN. 1 gram sets off about anything besides ANFO.
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XeonTheMGPony
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Metal tubes help to focus the blast wave and improve power and performance.
There is a reason for it, shrapnel is an annoying by product. FYI Most Properly made ANFO is not cap sensitive, why it is used so heavily in
industrial mining.
Average is a 1 pound Pentolite booster (PETN / TNT) or 20 to 30% Nitroglycerin Dynamite.
I've had very good success using 5grams ETN with a bit of Ammonium nitrate mixed in w/ Aluminium as the booster
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Rocinante
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Metal doesn't bend as easily so it protects the contens of the blasting cap, esp. the primary.
However, the is only a small difference between let's say 0.5 mm of aluminium and 2 mm of hard plastic as far as the impulse transfered to the main
charge. The metal one has the PETN/ETN closer to the explosive but it takes more energy to burst the casing than the plastic one. Both are not brittle
failures - they expand like a baloon and then they pop.
Where metal shines is when you want to press the secondary to high densities, plastic will not allow you to do that.
I'd recommend 0.3 or 0.2 mm Al tubes because these kind of fragments will decelerate to acceptable velocities within 25 m or so, the problem is that
they are not that easily avaliable in the required inner diamaters with nice, closed, round bottoms - no seals for the explosive to get into
(friction).
I supposed that the 22mag penetrated the wall with its bottom - the metal is rather thick in that reqion. Shell casing aren't ideal - dense, pliable
metal and thick parts give dangerous fragments.
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XeonTheMGPony
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go to the hobby store you can get nice aluminium tubing that is 6mm od by 5.5mm id, just have to seal the end some way for the secondary side, I use a
bit of painters tape during pressing and it stays on pretty good usually
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twelti
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What about something like this:
https://dragonplate.com/carbon-fiber-roll-wrapped-twill-tube...
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Herr Haber
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| Quote: Originally posted by Rocinante | | Inner tube 15 cm long, inner diamater 7 mm with 0.5 mm thick aluminium walls and a solid, round end filled with 350 mg of - yes, very lightly pressed
SA.DS. The tube contains e-match and the rest is filled with mineral wool,
sealed with epoxy. The outer tube is 15 mm inner diamater, |
So your assembly is 15cm long and 1,5 com wide...
One can only wonder how big your main charge is 
Or how you test a new EM.
If you really insist on several tubes:
Get a 6x4 mm tube and a 6x8mm
Get a 6mm bar.
Cut the bar in small discs: they will be your end plugs for the 8mm (outer) tube.
Cut your 8mm tube to desired length. 5 cm to 7,5 should be perfect. Place a disc at the entrance of one of these tubes then strike with hammer. You
may need to heat to outer tube to place the disc inside. No glue or epoxy should be needed. Maybe a file.
Now fill that tube with the amount of secondary needed. Press or melt.
Cut your 6mm tube to the same length as your 8mm tube. It will protrude from the 8mm tube since you now have your secondary in it.
Find thick Al foil / use Aluminium from Al trays you usually get at take aways. Glue / metal epoxy this foil to one end of your tube, trim with
scizors. Fill with primary / close as usual.
You may now insert the inner tube inside the outer tube or keep it dismounted until needed.
Since you can cut and load your outer tube to your heart's content it can be a detonator or a booster.
| Quote: Originally posted by XeonTheMGPony | | go to the hobby store you can get nice aluminium tubing that is 6mm od by 5.5mm id, just have to seal the end some way for the secondary side,
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Get a bar of the same diameter and cut 2-3 mm discs. You can now also use a piece as a dowel to press your EM.
You might need the discs in place with a hammer or glue them with epoxy if precision isnt good.
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Tkuze
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These are all really great designs. Ill keep you guys updated on new designs. Continue to share yours. Id love to see pics.
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wessonsmith
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Powerful, Safe, Reliable, Green detonators!
So I guess I will weigh in here on how to make very SAFE and reliable and very POWERFUL #8 detonators. First, for all of you using Lead Azide,
Styphnate, blah blah blah, STOP! Stop with the very sensitive primaries, PLEASE. If you are using HMTD, TATP then I guess you are looking for your
Darwin award.
So there are two methods I use to produce very powerful detonators, one being a bit more challenging than the other. The first is the 300mg Nickel
Hydrazine Nitrate (NHN), 200mg powdered ETN, 700mg Melt-cast ETN route. This is the easiest of the two to produce. Any tube, plastic(use 500mg NHN),
steel, aluminum, copper, etc. can be used with equally great results. The only drawback with this method is that you have a temperature limit of
58°C(136°F) in which the detonator can operate. This temperature limit, however, isn't an issue for 99% of those playing with energetics, so that
would be the one I would suggest.
For those of you who are interested in more exotic materials then you have the NHN / Sodium Nitrotetrazole(NaNTz) route. This is sexier because you
are using a tetrazole and the upper-temperature limit in which the detonator can be used is raised to 180°C. What I love about this method is
SAFETY. If you do your research on NHN you will see that NHN is 80x less sensitive to friction than Lead Azide but when you mix NHN with NaNTz
(80/20) you get a VERY insensitive mixture. NaNTz(Dihydrate) is so insensitive that you can't set it off with hammer blows, try that with Lead Azide.
The process for making the detonator is very simple. Intimately mix the NHN and NaNTz powder together by placing in a plastic container and shaking
vigorously. I like to push the mixture through a plastic strainer a few times to really ensure a thorough mix. Press mixture into a detonator tube and
place into a 107°C(225°F) oven for 4 hrs to drive off the 'water of crystallization' of the NaNTz and then you are left with a ready to go Anhydrous
NaNTz / NHN mixture. Place 50mg of NHN on top of that to help the Visco fuse or electric match head to set it off.
A quick note on Tetrazoles. DBX-1, Silver Nitrotetrazole, etc. are about as sensitive to friction as Lead Azide is, so in my book, that's just too
sensitive.
The beauty of the above designs is that the can sit on a shelf for a decade or more. None of the energetics used is reactive to aluminum, steel,
copper, plastic, etc. They are "Green Primaries" and both can be made from access to eBay and Amazon. I have put a few links to some videos below.
NHN manufacture:
https://youtu.be/rPxdDSUGxo4
NHN/NaNTz very simple detonator (plastic)
https://youtu.be/qbfaFi6g1ew
Power comparison between NHN alone and then mixed with NaNTz
https://youtu.be/1wvZ5sFZqVA
Video just for fun. Firecracker mix 1.25g (NHN/ETN) heat treated.
https://youtu.be/vibSy1i8YC4
Manufacture of 5-ATz
https://youtu.be/5s2yq3_yWjM
2017 Patent process for making NaNTz.
https://patentimages.storage.googleapis.com/01/67/21/181df61...
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Flawed Soul
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I use old aluminum arrows, cut to length and crimp one end in the vise. They work well. The end that the nock attaches to is already sealed, that part
makes great cap.
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hissingnoise
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I used to use aluminium (10mm?) freezer tubing, just crimped shut with pliers...
One time with RDX base with HMTD topping ─ the piece of builder's plank it sat on was chewed up, split in two, and I still found my original 3 inch
piece of Al tubing ─ though it was now in the form of a very delicate, fine glittery 'lace fabric' of probably a couple of feet or more in area...
I'll havta get myself more active again, one of these days.
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caterpillar
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I formed a tube, wrapping aluminum tinfoil around a pencil. 0.5-0.8 gr of TATP inside. Cotton rope, boiled in a solution of KNO3. Then this rope was
dried and put into liquid sulfur. Then wrapped with adhesive plaster. Pushed into that aluminum tube and fixed with the same plaster. Burned slowly
and stable. Powerful enough to initiate a mix of AN+ ammonium picrate.
Women are more perilous sometimes, than any hi explosive.
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wessonsmith
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| Quote: Originally posted by caterpillar | | I formed a tube, wrapping aluminum tinfoil around a pencil. 0.5-0.8 gr of TATP inside. Cotton rope, boiled in a solution of KNO3. Then this rope was
dried and put into liquid sulfur. Then wrapped with adhesive plaster. Pushed into that aluminum tube and fixed with the same plaster. Burned slowly
and stable. Powerful enough to initiate a mix of AN+ ammonium picrate. |
You lost me at TATP. When anyone says they are using TATP, HMTD, Lead Azide. etc I say you haven't spent enough time to learn how to make safer more
powerful primaries. I am not trying to be rude but just straight to the point. Yes, it is VERY easy to make TATP and HMTD but it's just as easy to
seriously hurt yourself.
I got into energetics about 3.5 years ago and from the very start, I wanted to find a better way than HMTD and TATP. I did the research on those
primaries and saw the potential for trouble. Not to mention the reactivity of those primaries.
Nickel Hydrazine Nitrate (NHN) is an incredibly stable, safe and very powerful primary.
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XeonTheMGPony
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| Quote: Originally posted by wessonsmith | | Quote: Originally posted by caterpillar | | I formed a tube, wrapping aluminum tinfoil around a pencil. 0.5-0.8 gr of TATP inside. Cotton rope, boiled in a solution of KNO3. Then this rope was
dried and put into liquid sulfur. Then wrapped with adhesive plaster. Pushed into that aluminum tube and fixed with the same plaster. Burned slowly
and stable. Powerful enough to initiate a mix of AN+ ammonium picrate. |
You lost me at TATP. When anyone says they are using TATP, HMTD, Lead Azide. etc I say you haven't spent enough time to learn how to make safer more
powerful primaries. I am not trying to be rude but just straight to the point. Yes, it is VERY easy to make TATP and HMTD but it's just as easy to
seriously hurt yourself.
I got into energetics about 3.5 years ago and from the very start, I wanted to find a better way than HMTD and TATP. I did the research on those
primaries and saw the potential for trouble. Not to mention the reactivity of those primaries.
Nickel Hydrazine Nitrate (NHN) is an incredibly stable, safe and very powerful primary. |
LMAO Ya the industrial military complex hasn't don enough research, the Mining industry hasn't, you have the one true truth!
you lost all credibility a while back in my eye's so not like you could lose any more.
You do realize the toxic properties of high concentration of Nickle?
So ya, simple facts, there are reasons they are still Using Azide, that superseded Fulminate, and Terazoles are slowly working to replace Azide for
green reasons.
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Tsjerk
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What is wrong with dextrinated lead azide? You only need a grain to set of PETN, of which you only need half a gram to set of ANNM
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caterpillar
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The White Devil (TATP) is dangerous, yeah, but mercury fulminate too. The rules are simple- use pure chems, HCl as catalyst (not H2SO4), make few
grams. I made more dangerous things with TATP- well, if you say that I was wrong mixing ten grams of TATP with AN, I'll agree. But the small amount in
a blusting cup can only throw one-two fingers away. No big deal. There is double salt- Ag2C2*AgNO3. Use it if you want- but do not forget to add a few
percents of graphite. It is static sensitive.
Women are more perilous sometimes, than any hi explosive.
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MineMan
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| Quote: Originally posted by XeonTheMGPony | | Quote: Originally posted by wessonsmith | | Quote: Originally posted by caterpillar | | I formed a tube, wrapping aluminum tinfoil around a pencil. 0.5-0.8 gr of TATP inside. Cotton rope, boiled in a solution of KNO3. Then this rope was
dried and put into liquid sulfur. Then wrapped with adhesive plaster. Pushed into that aluminum tube and fixed with the same plaster. Burned slowly
and stable. Powerful enough to initiate a mix of AN+ ammonium picrate. |
You lost me at TATP. When anyone says they are using TATP, HMTD, Lead Azide. etc I say you haven't spent enough time to learn how to make safer more
powerful primaries. I am not trying to be rude but just straight to the point. Yes, it is VERY easy to make TATP and HMTD but it's just as easy to
seriously hurt yourself.
I got into energetics about 3.5 years ago and from the very start, I wanted to find a better way than HMTD and TATP. I did the research on those
primaries and saw the potential for trouble. Not to mention the reactivity of those primaries.
Nickel Hydrazine Nitrate (NHN) is an incredibly stable, safe and very powerful primary. |
LMAO Ya the industrial military complex hasn't don enough research, the Mining industry hasn't, you have the one true truth!
you lost all credibility a while back in my eye's so not like you could lose any more.
You do realize the toxic properties of high concentration of Nickle?
So ya, simple facts, there are reasons they are still Using Azide, that superseded Fulminate, and Terazoles are slowly working to replace Azide for
green reasons. |
Actually Xeon. I can speak to this...
The mining industry and military does do a lot of research but they are too afraid of change (mining) or two slow to implement (military). For mining
it’s pure economics, orica makes thier caps in Mexico and they have tons of LA, so they keep using it, they don’t want to have to change thier
factory unless they need too.. The amateur will always have an adavatage in a sense. The mining industry needs to be pushed a lot, they don’t like
change. Especially the blasting industry. It’s embarrassing.
In the military HNS is still considered an experimental explosive.. and we have had that forever.
I appreciate Wesson’s contributions.
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